The Mind's I

Index

2007-02-14T06:04:00.001-08:00

Abelson, Robert P:, 473, 477
abstract categories. 31, 77
abstract formal products, 95
abstract machines, 62
abstract manifestation of person, 76
abstract mechanisms, 200-201
abstract nature of "hurricaneness," 77
abstract objects, 7
abstract patterns, 78
abstract structure, 78
abstract summary of global qualities, 199
abstraction, 97
accountability, 309; in face of uncertainty,
312
accuracy of replication, 129
accusative case, 408
Achilles, 149-91, 200; in Jardin du Luxembourg,
430-57
"Achilles book," 444-55
Acker, Sir Donald, 297
acoustico-retrieval, 152
acoustics, 138 acquired tastes, 428 active signals, 180
active symbols, 176-78, 180, 265
Adam, 126, 340, 346
ADAN, 309-16
adding machines, 358, 361; information processing by, 371
ADNA, 309-10, 312
afterlife, 328, 383; punishment in, 322
aggression of personoids, 308
aim of behavior, 134
"A-kill-ease," 447
Albert, Martin L., 477
algae, 121
Alice, 349-50
"aliveness" vs. "deadness," 448
"all at once" vs. "bit at a time," 432, 439, 450
52
Allah, 30 alligator, 434
allusions, 114
alphawaves, 112
alternate life-support media, 145
altruism, 142, 228
aluminum beetle, 111
ambiguous sentences, 14
Americans in Viet Nam war, 114
amino acids, 125; naturally occurring, 126
ammonia, 126
amoebae, 121
amusement park rides, 196
ANAD, 309-10
Analytical Engine, 63-64, 86
anarchism, 260
Anderson, Alan Ross, 470
Anderson, Cobb, 253-63
Andromeda, 137-39, 406
anemone, 121
anesthetic, 406
angels, 333
aroma, 122. 406
animals: behavior of, 142: consciousness of, 9, 392 feelings attributed to, 83, 134: having something in common with, 110; language facility of, 101, methods for study of 35 Self

concept of, 266, as survival machines, 134; see
also specific species
animate vs. inanimate matter, 121
animation, 212-13
animism, 114, 120
anomalies, 462
ant colonies, 146, 162-66, 168-76, 184, 192, 195,
199
ant trails, 165
antagonisms, mutually gravitating, 306
Anteater, 149-90
anthropology, 41
anthropocentrism, 80
anthropomorphism, 112, 192
antimatter, 388
antimonies, 306
ants, 114; individual personalities of, 335; see also ant colonies
"apeness," 35
apes: intentionality ascribed to, 365; language of,
106, 470
appetite, 395
apple: eaten by Adam, 340; event of seeing, 330
Arbib, Michael, 472
arcana of universe, 347
Arctic, climate of, 139
Aristotle, 6 Armstrong, D. M., 478
Arnauld, 237
art of listening to fugues, 191
artifacts, attribution of understanding to, 358
artificial flesh, 54
artificial information-processing devices, 233
artificial intelligence, 87, 193, 217, 233, 269, 274,
282, 343, 353-82, 465; critics of, 471-72; directions in current research on, 294; and otherminds, °56; and personetics, 317; of robots, 362-65, 471; self-understanding, 412; simplicity of simulations in, 318; skepticism about, 69; and state of technology, 366-67; and systems theory, 358-62
artificial sex, 309
artificial signaling, 377; of feeling by machines, 60
artists, 3 1
Asimov, Isaac, 263
assassination buffs, 462
asymmetry, 305
asympotic approach to sentience, 291
astronauts, 142
atheism: among personoids, 311; among psychiatrists, 330
atomic level, 36
atomic physics, 36, 39
atoms, 3, 34, 39, 98, 466; and anima, 122; complex patterns of, 124; envisioning of, 144; idea of being made of. 33; molecules formed from, 125: nuclei of. as hypothetical entities, 79; quantum mechanics of, 145; spirit as restlessness of, 120: stable pattern of, 125
ATTACCA, 159
Attneave, F., 473
attribution: of cognitive states, 358, 366: of emotions, 83. of intentionality,364, of understanding,358
auditory chauvinism. 434
auditory nerves, 232

auditory neurons, 438
Aunt Hillary. 164-66, 170, 174, 180-8I. 183-87. 192. 351
author, brain of, 47, 464
authoritarianism, 342 ,
autism. 469
autobiographers, primate, 460
automata, 392
automata theory, 275
automatic doors, 358
automatic mill, 109
automobiles, see cars autonomous structures. 192
Autotomy group . 269-73
awareness, 35, 122; see also consciousness; self
awareness
axioms, 424
axons, 435-36; in Einstein's brain book, 437, 441

Babbage, Charles, 63-64, 86
babies: consciousness of, 8; protectiveness to
ward, 108; whimpering of, 114
baboons, 106
Bach, _Johann Sebastian, 150, 153-55, 164, 186,
382, 405, 433, 449
bacteria, 121
Baker, Adolph, 467 bank robbery, 220
Banquo, 464
BAT-itude, 406, 410, 411
bats, 192; subjective experience of, 393-98, 402, 409-14
BATs, 406. 407, 411, 412, 478
Battens, Sir W'., 106
"batter's helmet," 410
Baum, I-. Frank, 236
"be-able things," see BATS
bearers of spirit, 122
beauty, nature of, 455, 456
beer, taste of, 428
bees, 31
Beethoven, Ludwig van, 433, 440
behavior, 31; animal, 142; of ant colony, 166, 168; collective, 191; diversity of, in machines, 63; external, 93; global principles of, 385; imitation of, by machines, 55; informality of, 65-66;and intentionality, 365; mental states as cause of, 392; molecular, 34; norms of, and study of animal societies, 41; organization of brain and control of, 10, 11, 14: purposeful, 172; self regarding, 266; simulation of, 73; social, 34; of survival machines, 134-37,139: understanding
indicated by, 366
behavioral science, 34
behavioral tests, 366
behavioral theories, 55
behaviorism, 93, 94, 107: and artificial intelligence, 371; causal, 400. 401; and personetics.308
beliefs, 196; of animals. 83: brain as storehouse of, 282; coded, 200: dichotomy between logic and, 314; false, 417-21, 425-26: in inanimate objects, 381; in life after death. 143; of machines, 361-62; as mental content, 369; and point of view, 221; unconscious, 12
"believing svstem," 277
Belinskv, Alexander. 100-6
Bennett, Charles, 342, 477
Berkeley, Bishop George, 299
Bert, 204. 206
BEX, 261
"Big Bang," 40, 125, 195. 460
Big Metal Hawley, 238

bio-chauvinism, 351
biochemical cocktail-shaker, 126
biochemistry. 372
biological history. 80
biological machines, 109
biology: integration of physics and psychiatry with, 39: materialism in, 34; molecular, 36: origin of thought, 41; principles of, 142: found mystery facing, 141
birth in game of Life. 319
-'black boxes;' 93, 94
Black Death, 396
black holes, 6, 458; of the mind, 279
Blackburn, Simon, 468
blasphemy, 325, 329, 331. 341
blind people: explaining experience of seeing 402; simulation of vision in, 231, 411-12, 4 sonar of, 397
"blind sight," 481
Block, Ned, 373, 469. 478, 479
blurring of levels, 380
boats, toy, 430. 437
Bobrow, Daniel G., 473
Boden, Margaret, 471
Bodhidharma, 45
body: brain located outside of, 218-40; carbon based, 250: as colony of genes. 134: control of 5, 95; dream of, 346; external symmetry 404; feedback principles in, 135; function without mind or soul, 383-84; hemoglobin molecules in, 125; implantation of mind 242-52; as machine, 367; manufacture of, 242; me-ness attached to viewpoint of, owning one's, 5: and propagation of genes 143; of robot, 21, 268; self as dream of, self inhabiting, 24; soul in, 47; tuning of n and, 248; as vessel to bear spirit, 121
body-image pathologies, 251
Body-switching, 5-7, 465
Boer, Steven, 467
bogies, belief in, 66
book plus process, 444; see also Achilles b Einstein book
hooks: copied by hand, 128; descriptions of people in, 21: as information transferring technology, 252; see also fictional characters
hoppers, 255. 256. 258-65
Borges,Jorge Luis, 19-20, 20-21, 42, 49, 344 348-52, 467, 476
Bouwsma, 0. K., 474
Bovine, 304
bovine genes, 385
Boysen, Sally, 470
Brahman, 30
Brahms, Johannes. 225. 232, 233
brain: activity of, 342: alphawave frequent 112; of author, 47; bat, 394; binary algebra circuits of, 291: blanked, 246. 251: car based, 259; causal powers of, 374; Cents Lions of, 304-6, 318; contrasted with comp 252: damage- 481-2; disembodied. 20'. 218-40. 473: dualist concept of, 388: ironic, 70: evolution of, 303-5; flexibility 200; and genes, 139; of God, 48: gridlock 273; haying vs. being, 5'~ hemisphere 203-8; histological examinations of, human, compared to chimpanzee, 105 language facility, 101: levels of, 182, 281; of description of 472; localized centres of functions in, 303: LSD in, 413: mapping 169, 177; mental states as product of, mind vs. (see mind vs. brain); neurobiological research on, 42; vs, neurons, 167, neurophysiology of. 369: owning one's, 5: potential reliving experience coded in, 156; processes

in, 11-12; and propagation of memes, 143; properties of sequences in, 367; questions about, 32; read on symbol level, 181, 183; reconstruction of sound in, 152; reductionist view of, 35, 162. 391; relation between experience and, 212; relationship of ideas to, 194; research on, 217; simulation capacity of, 141; simulation of. 363-64; spare, 22f>-31; stratified organization of, 199: structural integrity of, 449; structure and activity of, 435-36; as substrate of intelligence, 90; and survival machine, 141; thinking about one's, 174; tissues of, as vehicles of information. 268: transplanting of, 5-6; unique configuration of, 252; in the vat, 474; visual cortex of, 231; wind chime metaphor for, 197-98
Brain-book immortality. 458
brain damage, 409, 481-2 brain death, 106
brain-reading machine, 416, 419-26
brain state, 178, 182, 282
brainstorm, 77
brain-transplant thought experiments, 220, 466
brainwashing, 386
branchings in evolutionary tree, 87
Brandenberg concerto no. 2 (Bach), 381
Brccht, Gcotgc, 475
bridge, game of, 7
British Crown Jewels, 93
brotherhood of man, 464
Brown, G. E., 145
Bruhler, 225
bubbling up of conscious thoughts, 283
Buddha Nature, 30
Buddhism, 310
buffer storage of incoming information, 141
building blocks: letters as, 180; mathematical,
298; molecular, 127, 128, 130 burial rites, 226
Burns, Robert, 20
butterfly, metamorphosis of caterpillar into, 401
Buxtehude, Dietrich, 190
bypassing of lower levels. 182

C, middle, 213
Cadmus, Sally, 242, 244, 251
calculations, fake, 75
calligraphy, 154
calves, newborn, 385
Calvin, William H., 193, 473
cameras, 28, 29
canned sentences, 92 Cantor, 396
Canyon, 306
Capitan, W1. H., 478
Capra, Fritjof, 38
capricio-deterministic trajectories 386
carbon, 242
carbon dioxide, 126
Carroll, Lewis, 348, 444
cars: attribution of understanding to, 358: en
gines of, 11, 381
Cartesian mental substance, 371, 372
Cartesian negation, 224
cash registers, 75' ,
Cassander. 204-9, 212`
Castaneda, Hector-Neri, 467
caste distribution of ants, 168-76, 178, 187, 193. 199-200
Castler, 308
Cat, Schrodinger's, 38, 45. 46
CAT-scanning, 7
catatonia, simulation of, 91

categories, 192. 343; abstract, 31, 77
caterpillars, 401
cats, 31; and Turing test, 85
Caulfield, Holder, 406
causal behaviorism. 400, 401
causal powers, 362, 364, 365, 367, 369, 372, 374,
381; and "right stuff," 365-66
causality, I96-97, 343; of brain, 374; closed loop of. 281
cells, 27, 88; activity of, 35; body as colony of,134; first living, 131; physiology of, 36; proliferation of, 119; replacement of, 4
centrifugal force, 196
cerebroscope, see brain-reading machine
chains, molecular, 125
Chaitin, Gregory J., 342, 477
Chase, Mr.. 426-29
chauvinism, 80; auditors, 434: bio-, 351
chemical messages, 200
chemistry, 35, 54; of life forms, 142; life in terms
of, 85; of nuclear particles, 145; and raw
materials of life, 126
Cherniak, Christopher, 269-83
chess, 93, 199; computer, 55, 82, 83, 90, 136
Chess Challenger VII, 114 childhood, lessons of, 386
children: talking to trees by, 335; see also babies chimpanzees, 10; language of, 100-8, 273, 470;self-consciousness in, 471
China, experience of being, 192
Chinese room thought experiment, 355-69, 371,
373, 375-82, 459
Chinese subsystem, 360-61 chloride ions, 125
choice, 323, 336; see also free will
Chomsky, Noam, 106
Chopin, Frederic, 32, 107, 381, 406
Chopper, Nick, 236 Chris, 69-92
Christian Science, 425
Christianity, 57, 310
chromosomes. 133 Church, Alonzo, 58
Churchland, Patricia, 477, 479
Churchland, Paul, 479
Cinerama, 221, 238
cistron. 133
civilization, model of, 290 clairvoyance, 66
Clark, Arthur C., 276
classes: of activities. 124; formulation of, 31, 32
Clecklev, Hervev Ml., 479 Clever Hans, 480
cloning, 56: by Teleclone, 4, 7
closed-circuit television, 20
closed loop of causality, 281
closed vs. open systems, 451
Clossman,
Cars, 468
closure, 304
cobbler, 466
"coded" potential. 156
coding of meaning, 381-82 coffee tasting, 427-28
cognition, 368; simulation of, 353
cognitive development, 31
cognitive dissonance. 395
cognitive psychology, 12-14
cognitive science. 13-14,201,271,274.366,465, 470, 482
coincidence, 199. 462: of levels. 183
Colby, Kenneth Mi., 469
collective behavior, 191
Collins, Allan, 473
Color, perception of, 479
Columbus, Christopher, 296

coma, Riddle-induced, 270-76
commonsense, language of, 30
communication: among ants. 167; with ant colony. 165: lines of. 14; and primate language, 107; with universe by radio, 137-38; visual, 30
communism of ant colony, 169, 184-85
competition, 130-31
complementarity, 156, 173, 335
complexity. 124
"computational glasses," 75
computational operations on formal elements, 357, 363, 366, 367, 372
computer science, 317. 379
computer vision, 193
computers. 56, 88; of Andromedans, 138-39; capacity for thought of, 86-87 (see also artificial intelligence): chess-playing, 82, 83. 90, 136: consciousness of, 8: as duplicate of brain, 226, 230, 236-37; evolution of, 87-88; factory-fresh. 246, 252; "intelligent," 13, 86; and laws of physics, 75-76; meaning of word, 87; memory of, 74; mistakes made by, 87; and Riddle of the Universe, 269; robot controlled by, 21; see also programs; simulations
concepts: extending, 77; shift of, 196
conceptual slipping, 408
conclusion, errors of, 62-63
concrete material products, 95
concussion, 410
conditioned reflex, 63
conditioning, 107
conditions: of satisfaction, 362, 369; of understanding, 356
Confucius, 340
consciousness, 7-15, 32, 35, 39, 122, 134, 250, 274, 436, 466, 468, 470; in ant colony, 146; areas of brain involved in, 202; of body, 225; concepts of, 7-15; duplication of, 368; essence of, I81; evolution of, 141, 468-9; feeling of, programmed into computer, 264, 265, 267; and free will, 339; as gift, 305; interlevel feedback in, 281; levels of, 85, 380--81: mind as home of, 224; and mind-body problem, 391, 392: in objection to thinking by machines, 5961, 63; organic subject of, 233; person as center of, 7; personoid, 318; and primal loop. 283; and quantum mechanics, 39. 42, 43; and reductionism, 162, 392-93: riddles of, 458: selfregarding behavior without, 266; and spirit, 120; thought and feeling in, 81; theory of, 303-5; undeniability of one's own, 387; universe without, 386
content, see form vs. content contexts, 413
continual loop between levels. 343
contradictions, 306, 424, 425; belief in, 315; of
brain, 304-6, 318; interlevel. 277; and personoids, 301
control: levels of, 304: of the body as the mind's product, 95; of self, 453; subsystems fighting for, 342
conspiracy buffs, 462
"conspiracy theory," 33
conventions, 114
Conwas. John Horton, 319
Copernicus, 58, 144, 458
copy of individual, 408
copying fidelity of replicators. 128, 131
corpus callosum, 14
Cosmic Process, 334
cosmos, synthetic, 298
counterexamples of theorems, 151, 153
countries: activity in, 342; behavior of, 191; symbol level of, 192, 193

cows: idea of killing, 114; moo of, 162; simulation
of, 94, 372; soul of, 386
Crab, 149-90
creational interventions, 300
creative self, dichotomy of, 283
creativity. 86, 294
Creator of pet sonoids, 303, 310, 314-17
Crick, Frances, 36, 39
critical mass, 168
crystals, formation of, 125
C3PO, 87
Cube, Magic. 342
Cube with Magic Ribbons (Escher), 156
cubes, 125
cults, 386
culture: of personoids, 303: replicators of, 142-44
currency: for exchange of ideas, 413; of signs and patterns, 107
curvature of space, 458
Cushing, Annie, 253, 258
cybernetic universe, 318
cybernetic wobble, 426
cybernetics, 297

DAAN, 309-10
dactylic hexameter, 13
daisy, plucking petals off, 47
damnation, 328
DANA, 309-10
Darling, Candy-245,247-49
Darwin, Charles, 124. 129, 130, 133
Darwinian epic, 460
Darwinians. 35, 36
data banks, 358
Davidson, Donald, 401, 468, 478
Davies, Paul, 48, 468
da Vinci, Leonardo, 144. 434, 440
Davis, Lawrence, 474
Dawkins, Richard, 122-23, 124-46, 195, 458, 472
Day of judgment, 464
death, 348; anticipation of. 105; experiencing, everywhere but "here," 411; fear of, 291; in Game of Life, 319; general concept of, 31;hurting others by one's. 383; life after, belief in, 143: of Martha. 106; meaning of, Ill; of mind, 244: questions about, 32; resistance to, 110, 115; simulation of, 308; and spirit, 121; terror of, 255-57; unacceptability of notion of own, 30
DEC PDP-10 computer. 380, 412
decoding of chime state, 199
degrees of understanding, 357
De Long, Howard, 470
Demand characteristics, 480
demiurgi, 346
Demon: Descartes Evil, 213, 473-4: Haugeland's 376-8; Searle's, 376, 378, 380
Dennett. Daniel, 73. 75, 84. 217-29, 230-33, 235 38. 240, 351, 375. 408, 466. 468, 473, 475-78 De Reinzie. 242
Descartes, Rene, 35, 213. 237, 238, 318, 350, 388, 462,473-74
Desdemona, 464
design, 120
desire(s). 84.95. 134. 196: of animals. 83: of computers, 83; and spirit, 120; unconscious, 12
desolation. 288
de Sousa. Ronald, 230-31. 473
destruction: of animals. 105: of inanimate objects, 114
determinism, 320, 323. 337-38, 343; in soul-free universe- 386

devil, nature of, 334, 342
Dewitt, B. S., 468
Di of Antus, 188
dialectics of dreams, 345
diamond crystals, 125
dice playing, 45, 48
dichotic listening tests, 14, 466
dichotomy, 158; between logic and belief, 314
Dickens, Charles, 179, 182
differentiation of personoids, 302
digestion, 8, 361
digital computers, 56, 59, 61, 64; capacity to think of, 368
digital model, 97
dimensionality, 298, 309
Diophantus, 150, 153
direct evidence, 80
direct perception, 76
direction of fit, 362, 369
Dirksen, Lee, 109-13, 115
discrete state machine, 65
discrimination tests, 428
disembodied brains, 202-12, 217-31, 473
Dizzard, C., 269-75
DNA, 80, 88, 89, 94, 127, 128, 142, 404, 406, 458; interactions of RNA and, 274; recombinant, 271; as template, 242
Dobb, Professor, 296, 299-317
dogs. 9, 31, 273; capacity for thought of, 32; in tentionality ascribed to, 365; and Turing test, 85
dolphins, 9. 253
domino-chain network, 194-95
Doney, Willis, 474
doom, recognition of, 113, 115
doors: automatic, 358; of brain, 452
Doppelganger, 327, 413, 474
double bind, 325
double blind experiments, 480
"double-take," 20
Douglas firs, 121
downward causality, 196, 197, 343
dreamed people, 345-48, 350, 406, 462
dreams, 8, 96, 98, 250; "Am I My Body's Dream?," 346; Descartes on, 350-51; without dreamers, 351; not remembered, 412
dream-writing machines, 458
Dreyfus, Hubert, 373, 471
drinking, 255
drives, global coherence of, 386
dualism, 268, 343, 371-72, 381, 383-88, 407, 476, 477, 478
Du Bois-Reymond, Emil, 36
duplicate people, 474-5
duplication, distinction between simulation and, 369-71
duty, 341
Dykes, Robert, 478

ears: hearing without, 225; sound hitting, 438
Earth, 32, 458; communication from Andromeda to, 137-38; cultural riches of, 259; duplicate, 231; eternal course of, 340; evolution of life on, 460; finite size of, 130: life on, 125; spaceship link between Moon and, 261; stable forms on, 125; teleportation from Mars to, 3, 4, 7
Eastern philosophy, 341
Eccles, John, 477
echolocation, 393
ecology, 140
economics, 140
ecosystems, destruction of, 41
ecstasy, 95, 348

EDAN, 310, 311
EDNA, 291, 297
Edwards, Jonathan, 329 ego(s), 8, 12; merging of, 307 egocentric point of view, 410 eigenstates, 43-44; random, 45
Einstein, Albert, 37, 45, 48, 196, 413, 458; vs
book, 442
Einstein book, 434-45, 450, 452, 459
electric sparks, 126
electrocuted person, 406
electrodes, 35
electroencephalograms, 270
"electronic brains," 372
electrons, 213,292:influence of thoughton,195; minuscule capering of, 291; path of, 193; weaving the universe, 318, 458
elements, 125
ELIZA, 251, 254, 469
Elizabeth II, Queen of England, 144
Elliot, John, 137
embedded dialogue, 434-37
embryonic development, 131, 139
emergence: of person, 86, 352; of properties, 144; of self-consciousness, 41-2, 468
emotions, 11, 450; appeals to, 114; attribution of, 83; as automatic side effects to thinking, 81; avoidance of references to, 81; and intellect, 84, 107; and machines, 60; of personoids, 302, 305; size irrelevant to experience of, 289
empathy, 114; vs. emulation, 412; see also mapping empirical questions, I I
emulation, 56, 379-80, 412, 477
encephalitis, 482
encoding of knowledge, 171, 176 "end in view," 134
energy, 126, 127; matter as, 401; of system, 39 engineering, 54, 56
English, understanding, 355-60, 363-67, 378
79,405
English subsystem, 359, 360, 379
engulfing: of mind by mind, 375; of program by human brain, 359, 364
enlightenment, 333, 342, 463; meditative, 273 74
entelechies, 144
entities, differential survival of, 132
entropy, 39
envy of God, 329
enzymes, 89
epiphenomenalism, 388
epistemology, 37, 415-29; circular, 39-40, 42; personoid, 310
Ericsson, K. Anders, 471
errors: of conclusion, 62-63; first-order vs. second-order, 277; of functioning, 62-63
Escher, M. C., 156, 174, 221
esse, 299
essence, 122; of hurricanehood, 78; of living, 113; of mental, 364-65, 370
eternal life, 328, 329
eternal punishment, 317
eternity, 120
ethics: and amorality, 340; of research, 275-76: temporal vs. transcendental, 313
euphemistic synonyms, 114
Everett, Hugh, III, 45-46, 49, 458, 468
evidence, evaluation of, 201
evil, 462; concept of, of personoids, 308, 312; illumination of, 120; and punishment, 329; as suffering, 333
evil temptations, 322, 328, 333
evolution, 88, 121, 128-29, 199, 460, 468, 477; of ant colonies, 173; based on replicators other

than DNA, 142; and coding of global principles into synaptic structure, 385; of computers 87-88, ; of consciousness, 141-303-5 Cosmic, 333; Darwin's theory of, 124, 317; discontinuity in, 40: and errors in copying, 128; hereditary arrangements in, 119; linguistic, 302; of machines, 113; of molecules, 125; seemingly purposeful path of, 122; time before, 124
evolutionary biology, 196
evolutionists, 35
Excelsius of Tartarian, 288-90, 292-94
excluded middle, law of, 357
excretion, true nature of, 114
existence: of categories of things, 6-7; entities, 124-25; deep problem of, 124; of God, 311-16, 319, 320, 332; incomprehensible qualitv of, 33; of minds and selves, 466; ontological foundation of, 316
existential residence, 299
experience, 8, 25, 26; as basis for imagination, 394; conscious, 13; in language of sages, 30; mind as pattern of, 246; maximum brain can encompass of, 248-49; of mathematics, 301; neural theory of, 202-12; of personoids, 301; privacy of, 396; r e-creation of, 29; reducibility of, objection to, 399; as sentience, 406; subjeo tive character of, 14, 392-93, 395-96, 402-3, 409-14
Experimental Epistemologist, 415-26
experiments, 111
explanatory power, 179 exploratory initiative, 299
extending: of concepts, 77; of verb "to be," 78. 409
extrapolation, 394
extrasensory perception (ESP), 66-67, 470 eyes, 24, 26, 30, 219; artificial, 231; evolution of, 132; innocent, 27; of others, 24; tracking moving object with, 222
evevideos, 233, 234, 237-4!

facts: humanly inaccessible, 396; relationship between representational systems and, 396
failures, 287
Fall of Man, 340 fame, 20, 287
familiarity, 155
fantasies, 457, 458; philosophical, 230
Farker, 254-55
fascination, 121
Faught, W. S., 469
fear: in bat experience, 395; of death, 291
fecundity of replicators, 129, 131
feedback, 102, 426; absorbed by neurons, 385; artificial body controlled by, 235; between brain and body, 222; level-crossing, 85; negative, 135
"feed-forward," 135
feeling, 109; capacity for, 81; of emotions, 450
feelingless intelligence, 83, 84
feelings: brain as storehouse of, 282; imputed to animals, 134; of inanimate objects, 381; of machines, 113; nature of, 452, 456; of personal consciousness, 264-8; of personoids, 301;represented bsystem's state, 200 Feigenbaum, E.,'477 Feinman, judge, 100, 104 Feldman, J., 477
femininity, 72
Fermant, Johant Sebastiant, 186-90
fermat, 186
Fermat, Pierre de, 149-51, 186
fermatas, 183. 185 489

Fermat's Last Theorem, 150, 153, 186, 190
ferns, 121
Feynman, Richard, 44, 467
fictional characters, 47, 350-51, 461-64, 476; as real but nonphysical people, 387
"fictitious forces," 196
filing of memories, 282
film directors, 29
filtering and categories, 84
Findler, Nicholas V., 473
fire: god of, 344, 346, 348; simulation of, 370; see also flame
"first-generation" errors, 128
first-person perspective, 20, 29, 30, 268
fish, 121; feelings of, 82
five-alarm fire, 370
flame: internal, 86, 88, 90; as metaphor for soul, 408-9; spirit as, 120
flattening, 385, 386
flesh, artificial, 54
flexibility of computers, 381
flickering lights, 86
flutzpah, 49
focusing lens, 141
Fodor, Jerry, 318n, 475-77
folklore. 274
food gathering, 171
football pools, 127
footraces, 431, 457
forest: sound of tree falling in, 44; vs. trees, 161, 165, 166, 459
form vs. content, 153, 375, 406
formal principles, 357
formal shape, 369
formalization, 424 Fortinbras, 226-28 Foster, L., 478
four-color theorem, 269
four-dimensional hypersurfaces, 262
Fourmi, Lierre de, 188
Fourmi's Well-Tested Conjecture, 188
Fouts, Roger, 470
Frank, 415-26
Frankfurt, Harry, 474 Fred, 203
free will, 36, 198, 265, 283, 320, 453-54, 473, 476-77;removal of, 321-29, 332, 335-39, 341 43; as sentience, 406; universe without, 386
"free will paintbrush," 339
freedom, 120-22; of action, 300; of ants, 166; of personoids, 301; reprogramming of hoppers for, 264
French, understanding of, 358
frequency analysis, 141
Freud, Sigmund, 12 Freud's Crutch, 11-15
Frisby, John R., 475
Fugue's Last Fermata, 186
fugues, 154-59, 164, 173, 183, 190; improvisation of, 405; relationship between preludes and, 154-55
full system: determination of symbols by, 181; perception at level of, 200
functional states. 392
functionalism, 363, 371
functioning, errors of, 62-63
funneling, 282
future, prediction of, 197

G (note), 183
galaxies, 125; mapping of, 120; spiraled, 122, 14!
Galileo, 58, 458, 459
Gallup, Gordon G., Jr., 471

game of Life, 319-20, 385, 476
game theory, 312
Gandhi, Indira, 407
Garden of Eden, 340
"Garden of Forking Paths," 42, 482
Gardner, Allen, 470
Gardner, Beatrice, 470
Gardner, Howard, 481
Gardner, Martin, 476
Garrett, Merrill, 14, 466
gases, 145, 168, 170; atmospheric, 126; in soap bubbles, 125
GAX, 259
Gazzaniga, Michael, 481
Geach, Peter, 467
Gebhardt, 304
gee!, 184
general relativity, see relativity, theory of
genes, 129, 472; bovine, 385; neural patterns coded for in, 386; passing on of, 144; selfish, 123-34; survival machines for, 131-34, 137, 140, 141, 458
geology, 35
geometry, 298; non-Euclidean, 374
German: identity-asserting sentences in, 408; understanding of, 358 germ-line, 119
"ghost-inside-the-machine," 6, 450
ghosts, 5, 7; belief in, 66; novel writing as manu
facture of, 387
Gibson, James J., 467
Gilbert, 351
gliders, 320
"glitches," 77
global behavior, 385, 386
Globus, G., 472
gnosticism, 346
goalism, 197
goals: individual, 192; natural objects without, 120
God, 30; as author, 464; consistency of, 315; creation of universe five days ago by, 231; in dialogue with Mortal, 321-4!; and dice-playing, 45, 48; existence of, 311-16, 319, 320; false conception of, 330; immortal soul given by, 57; nature of, 330; as process and scheme, 333-34; universal wave function as brain of, 48; what is it like to be?, 406
god: of fire, 344, 346, 348; spirit as, 120
Gödel, Kurt, 277, 283
Gödel sentences, 274, 276, 475
Godelization, 306, 318
Gödel’s Theorem, 58-59, 343, 414
Goethe, Johann Wolfgang von, 338
goldfish, 114
Goodall, Jane von Lawick, 470
goodness: of angels, 333; concept of, of personoids, 308; illumination of, 120; and reward, 329 "gooks," 114
Gordon, G., 475
Gospels, 128
Gosper, Bill, 319, 320
government: of microminiaturized society, 289 structure of, 342
Graham, N., 468
grammar, deficient. 102, 106
grapefruit, thrown, 451
gravity, 125, 196, 339
Great Experience Feed, 207
Great Pyramids, 382
Gregg. Lee W., 473
Gregory, R. L., 466, 475
Griffin, Donald, 470
grooves of records, 432
Grunion. 121

guided missiles, 135
guillotined person, 406
Guinea, 106
Gunderson, Keith, 474
Gunkel, Pat, 240
Gustafson, D. F., 476

haircuts, 6, 164
hallucinations, 25, 225, 332, 346 ham radio, 76
hamburgers, stories about, 354, 359
Hamlet: Dennett's, 220, 226, 227, 232, 233, 235, 238, 351; Shakespeare's, 381, 462, 464 hand simulation of Al program, 373-74, 459 happiness, 329
Harding, D. E., 23-30, 31-33
Harman, G., 468
harmony, 155
harpsichord, 153
Hartree, 63
Haugeland, John, 373, 376-78, 471, 475
Haugeland's demon, 376-78
he-symbol, 266
head: electrons jumping around in, 292; firing of neurons in, 210-1 l; having no, 23-30, 467
headless monsters, 29
hearing: of computers, 87; through sounds, 379
heart, 360; beats of, 119; dream of, 346; evolution of, 132
heaven, 120, 340
Hechinger, Nancy, 412
Hegelian world substance, 371
Heisenberg, Werner, 38
Heiser, J. F., 469
helium, 125
hell, 120
Heller, Erich, 121
Hemingway, Ernest, 256
hemispheres of brain, 14
hemoglobin, 125 Hendrix, Jimi, 255
"hereafter" for personoids, 317
"here-centered, now-centered" frame of refer ence, 410, 411
hereditary units, 133
heterosexuality, 250
hierarchical conflicts of operation, 304
high-level vs. low-level description. 178
high-school students, 107
higher-level beings, 166, 192
higher-level laws, 174
higher levels of structure, 320
Hinayan Buddhists, 334
hippies, 258
Hofstadter, Douglas R., 69-95, 149-201, 265, 408, 430-57, 468, 470, 472, 475
holes: existence of. 6, 466; see also black holes
holism, 159-62, 173, 182, 190, 196-97, 338, 472; vs. reductionism, 162; translatability of reductionism and, 196
holismionism, 190 Holmes, Captain, 106 Homer, 444, 468
homunculi. 13, 305, 342, 362-63, 458, 473
Honderich, Ted, 476 Hope, Bob, 20
Hopkins Beast, the, 471
hormonal components of behavior, 36
horses, 480
houseflies, 10
Howell, Robert, 476
Hoyle, Fred, 137
Hubert, 226-31

Hughes, 299
Hughes, Howard, 217
Hughes, Patrick, 475
human condition, 72
human nature, 33
humanism, 38, 41; and scientific world view, 122
humanly inaccessible facts, 396
humor, 81
humpback whales, 138
Humphrey, N. K., 143
Humpty Dumpty, 187
Huneker, James, 107
hunger, 395
Hunt, Jason, 100, 101, 104-5, 109-13
hurricanes, 361; simulation of, 73-78
hurting: of sentient beings, 328; see also suffering
Huxley, Aldous, 38
Huxley, Thomas, 36
hydrogen, 125, 145, 242
hypothesis testing, 12

"I": active, 29; and dualism, 384; "here" and "now" and, 411; ineradicable sense of, 278; and interlevel feedback, 281; location of. 219. 220, 222, 223, 445; and memory, 4; nature of, 23, 27, 167, 181, 265, 306, 445, 450, 452, 453, 455,456,464; and self-recognition, 19-20; survival of, 227; in syllogism, 31; as used by machines, 411
Id, 12 idealism, 39
ideas, 8; mapping letters onto, 179; relationship of brain to, 194; storage of, 199, 282
identification, 114, 400; psychophysical, 391; see also mapping
identity, 4; mistaken, 29; of selves, 7
identity dilemmas, 445, 456
identity schemata, 297
ideology of strong Al, 359
idiots, 105
"If I were you ... ," 408
illusions, universe filled with, 386
imagery, 114
imagination, 23, 141, 222, 457, 459; experience as basis for, 394, 402; symbolic, 400; transcending interspecies barriers, 397
imbeciles, 105
imitation, unit of, 143
imitation game, 53-55, 57, 59, 65, 71-73, 92
immortality, 257-60; of genes, 133; in personetics, 302, 303, 308; through memes, 144
impedence match, 409
implementational levels, 380
impulse programmer, 206, 212
inconsistencies, 418
indeterminism, 42
indirect evidence, 80
indirect self-reference, 184
individual vs. class, 396
indivisible particulateness, 133
induction, scientific, 61, 63
Industrial Revolution, 86
Ineffabelle, Princess, 96-98
"I-ness," 47
infantile autism, 469
infatuation, 155
inference, 12
infinite regress, 200, 421
infinity, 315; simulation of, 308
information, 11; abstract piece of, coma induced by. 272; brain tissues as vehicles of, 268; buffer storage of, 141; encoding of, 41, 176; about size of nervous impulse. 65

information processing, 12-15, 370-71by stomach, 360, 361; technology of, 299
informational facsimile, 97
informational standing waves, 303
inner conflict, 342
"inner eye," 200
inner life, 9, 10, 13-14, 406
inner light, 9, 10
input-output patterns, 364, 371
insects, feelings attributed to, 83
inside, consciousness from, 8, 10
insomnia, 346
instantiating formal program, 364-f
instructions, 449
integrated circuit chips, 374
intellect: and emotionality, 107; human 59
intellectronics, 297
intellectual quarantine, 275
intellectualism, ant, 164
intelligence, 9; brain as substrate for, 90; candidates for, 93, of chimpanzees, 103; creation of, 316; development of higher and higher, 345, and emotions, 84; and evolution of brain 304 and formulation of classes, 31; incorporeal, 301; and individual brain cells, 166, machine,89; mistake-making as sign of, 89; real test of, 80, ; and reconfiguration, 200; reduced to behavior, 93; robot, 263; as sentience, 406; of societies, 472; synthetic, 305, 308; see also artificial intelligence
intention, 449; natural objects without
intentional stance, 84-85
intentionality, 358, 362-69, 371-7,defined, 358n, potion to do away with, 384; psychophysical theory applied to, 401; and subjective character of experience, 392
interacting particles, 145
interactionism, 388
interference effects, 44 .
interferon, 257, 258
interlevel feedback, 279 i
ntermediate levels: of organization, 175; of structure, 176
intermodal analogies, 402
internal combustion engines, 11
interneurons, 194
interpretation, 382; of information,370
interspecies barriers, 397
introactive causality, 197
introspection, 10, 12, 134, 451; reliability of, 471; and self-image, 41
introspective psychology, 369
intuition, 10, 46, 85, 99; logic overriding,32; primal, 335
intuition pumps, 375, 459
inverted spectrum, 479
inverting lenses, 412, 475
invisibility of lower levels, 89
Inward Power, 340
IQ test, 71
irony, 184
irreducibly mental properties, 401
"is," apparent clarity of word, 41
Ishmael, 350, 387
isomorphic self-symbols, 413

Jack the Ripper, 387
Jackson, Philip C., 471
James, William, 42
Jammer, Max, 467
Jansson, Gunnar, 475
Jardin du Luxembourg, 430, 436
Jauch. J... 467

Jaynes, Julian, 468-69
jealousy, 48
Jefferson, Professor, 60, 63, 377
Jesus Christ, 482
Jews, 114
Jodrell Bank radio telescope, 138
Johant Sebastiant's Well-Tested Conjecture, 189
John, E. R., 11, 466
JOHNNIAC, 350, 351
joint activation of self-symbol, 200
jokes: capacity to understand, 80; causing people to die laughing, 276
Jupiter, 419
justice: of God, 312; sense of, 329

Kafka, Franz, 409
Kaikki, Eino, 296
Kandel, Michael, 99
Kantianism, 328
Kaufmann, Walter, 469
Keller, Helen, 15, 482
Kenny, Anthony, 474
Kent, Clark, 388
Keyes, Daniel, 409
kitten, mew of, 162
Klane, Anatole, 110, 111
Klapaucius, 287-88, 290-94
Kleene, S. C., 58
knob settings, on intuition pump, 376
knowledge, 414, 473; encoded in caste distribution of ants, 171; and Fall of Man, 340; of own beliefs, 421; pieces of, 170; and power, 313;representation of, 170, 201, 473; storage of,176
Koestler, Arthur, 473
Kohler, Ivo, 475
Kripke, Saul, 400, 468, 478
Kyo-gen, 45

"labeled rooms," 452, 453
Lackner, James R., 14, 466
lactation, 94; simulation of, 372
laissez-faire, 185
language, 7, 470; and beliefs, 369; and consciousness, 470-71; difficulty with, 46, 48; facility of animals for, 100-8; learning new, 412; mastery of, 164, 177; as measure of soul, 107; as media of projection, 413-14; of personoids, 302, 309-11; processing of, 363; propositions expressible in, 396; self-protection through, 114; and self-regarding behavior, 267; simulation of ability to use, 294; slips of, 428; thinking in, 477; of thought, 274; understanding, 37840
Lao-tse, 340
Lashley, Karl, 13
last-minute transformation rules. 378
Latin, existence of, 7
"Laws of Nature," 477
layers of structure, 168, 176
L-dopa, 482
learning, 9, 142, 294; by an ant colony, 472; conditioned reflex as basis for, 63; modeling, 282
Ledoux, Joseph, 481
Legionnaire's Disease, 271
Leiber, Justin, 241, 242-52, 252
Leighton, Robert, 467
Lem, Stanislaw, 96-99, 287-94, 296-320, 408, 413
lemmings, 121
Lenneberg, E. H., 470
leprosy, 344

letter by letter reading, 179
level-crossing feedback loop, 85
level-crossing problems, 282
level-mingling, 380
levels, 158; of accuracy, 376; of ant colony, 146; coincidence of, 183; conflicts between, 318; confusion of. 74; continual loop between, 343; contradictions between, 277; of control, 304; of description, 84; difference in, 166; of explanation, 472; higher, 169; of implementation, 380-81; intermediate, 168, 176; mechanical, of molecules, 89; of mental operations and brain operations, 369; microscopic, 171; between principles and particles, 385; and process of creating self, 352; symbol, 182, 192; thinking on different, 336; underlying sets of, 177; of understanding, 357, 379; where meaning is visible, 173; of wholes and parts, 196; in windchime system, 198
Lewis, David, 466, 467, 475, 476
Lewis, Stephanie, 466
libertarianism, 185
Libet, Benjamin, 477
Library of Congress, 7
Lichtenberg, Georg, 278
life, 122; ancestors of, 130; beginning of, 124; biological, as complex form of machinery, 109; after death, belief in, 143; on Earth, 125; general principle true of all forms of, 142; machines as form of, 110; meaning of, 111; origin of, 126, 144; respect for, 110; study of, at all levels, 34
Life, game of, 319-20, 385, 476
light: returning through universe to point of departure, 287; seeing the, 334; speed of,32,137, 222, 224, 318; traveling in straight line, 120
lightning, 86; objective character of, 397-98; primordial, 126
linguistic ability, innate, 107
linguistics, 274, 470
liquids, 145
literary critics, 463
literary dualism, 384-88, 476
literature, emotional responses to, 81
Little Engine that Could, 268
Little Hawley, 236, 238
"little people," 200; see also homunculi
livers, 6. 360
lizards, 121
lobotomy, 35
lobsters, 266-67
"local" stimuli, 385
location: of consciousness, paradox of, 61; of person, 24, 27
Locke, John, 11, 13, 220, 465, 479
logic, 32; applicability to real world of, 343; internal, of representational systems, 193; mathematical, 58; multivalent, 311; overriding intuition, 32; of personoids' world, 301, 306, 313, 314, 317; rise of modern, 273; symbolic, 424; traps of, 431
"logical stupor," 304
longevity of replicators, 128, 129, 131
looplike self-reference, 279
loops, 194
loudspeakers, 432
love, 95, 121; and artificial intelligence, 370; created by spirit, 121; for person without soul, 384; and personetics, 316
Lovelace, Lady, 63-64
low-level explanation, 195
LSD, 412-13
Lucas, J. R., 277, 470, 475
lucidity, 346
Luria, A. R., 481

lust, 121, 395
Lycan, William, 467, 473

Macbeth, 464
McCarthy, John, 477, 361
McCorduck, Pamela, 472
machines: ability to think of, 53-67, 70, 84 (see also artificial intelligence); chess played by, 82; intelligent, 89; killing of, 111-13; mechanicalness of, 87-88; regarding oneself as, 110; subconscious concept of, 86; translations by, 99; see also computers
McMurrin, Sterling, 478
macroscopic domain, 144
madness, 463
Madonna of the Rocks (Leonardo), 440
magic, 345, 346
Magic Cube, 342
magic pill, free-will removing, 322-23
magnetism, 8
Mahayana Buddhists, 334 -
mammals: conscious experience of, 392; intentional stance toward, 85; see also specificspecies
man in imitation game, 71-72
manipulation, 114
many-body problem, 145 many-celled bodies, 134 Many Mansions, 366-67 many-layered system, 201
many-worlds interpretation of quantum mechanics, 44-46
mapping, 378, 382, 404-5, 409, 412; of persononto ant colony, 192
maps, 140
Marconi, Guglielmo, 144
Margolis, A., 477
Mark III Beast, 111-13, 267, 471
Marks, Charles, 481
Mars, 126; radio communication between Earth and, 137; teleportation to Earth from, 3, 6, 7
MARS, see Motion and Resistance Systems
Marshall, J., 481
Martha, 101-7
Martians, 367; subjective experience of, 395-97
Marvell, Andrew, 294
masochism, 432 mass, 120
materialism, 34, 391, 459; and subjective character of mental phenomena, 392
mathematics, 64, 150, 151, 188, 274; and computer memory, 297; epistemological problems in, 414; of matter, 144-45; mirror puzzle in, 404; and objection to machines thinking. 58 59; of personoid cosmos, 298-302, 306-8; phenomenalism of, 301; worlds made of, 318
matter, 97, 122; as energy, 401; mathematics of, 144-45; vs. mind, 416
matter oriented mechanism, 86
Matterhorn, 124
Mattuck, Richard D., 145, 473
Maxwell, G., 472
Maxwell, James, 37
"me" as used by machines, 411
meaning: as hypothetical mental quality, 107; of 445; of life and death, 111; meaning of word, 456; vs. meaninglessness, 172; perversion of, in copies, 128; of physicalism, 400; and symbols, 370; and understanding, 357, 374, 379; of words, 30, 32, 428, 455-56
meaninglessness, 172; of formal symbol manipulation, 368: of squiggles and squoggles, 377
Means, Germaine, 246-251

measurement, 38; of brain states, 420
meat eating, 114
mechanical page-turner, 447
mechanism, 82, 109, 197, 277, 283; and interpretation of real world, 300; pattern oriented, 86; of soul-free universe, 386
meditations, 348
meditative enlightenment, 273-74
Melville, Herman. 350
memes, 142-44, 145, 413
memory, 122, 243, 246, 436, 481; absent accumulation of, 7; of body, 225; in book lus-process, 444; in brain process, 12; carved in stone, 119; computer's, 74, 76; extra from, 4; in game of Life, 319; and ' time, 453; long-term, 410-11; not continually conscious, 12; searching of, 12; she 261, 410-11; and spirit, 120; and structure, 282; two people having same, 307
memory-decoding glasses, 76
Mendel, Gregor, 133
me-ness, 48
mental events, 401
mental images, 21
mental life, intimacy between person at mental magnetism, 196
"mental pictures," 134
mental representation, I I
mental states, 362, 416; of animals, 365;as a cause of behavior, 392; imagining, 400; simulation of, 358, 365, 369-73
"mentalism," 39, 83
mentality, like milk or like a song, 95
mental-nonmental distinction, 361
Meredith, Marsha, 468
Merrill, D. D., 478
messages: between brain and subsystems, 13; chemical, 200
me-symbol, 266
metamagical themas, 69-92
metamathematical limitative theorems, 469
metamorphosis, insect, 401
metaphors, 192; of cognitive function consciousness, 304-5; for thinking about souls, 281
metaphysics, 337, 339; experiments in, 310; mind vs. matter, 416
metaprogramming, 261, 262, 264
methane, 126
MEX, 259, 261
mice, 393; trapping of, 110
Michelangelo, 212 microbes, 113
microchiroptera, 393
Microminians, Moon of, 294
microminiaturization, 289, 376
Miedaner, Terrell, 100-8, 109-15 milk, 94, 95, 372 mimicry, 307
mind, 25, 122, 466; and artificial intelligence 382, 355, 360, 364, 371-72; attached to body, 47; attributed "soul" as image in, 114; black hole of 279; boundaries of, 11; vs brain, 369,431,436,438,439,455,459; of chimpanzee 105; consequences of fact presented to 65; contents of, 38; dichotomy of conscious and unconscious, 283; epistemological circularity in view of, 39-40; functional components of, 14; of God, 48; grades of sophistication, 382: as home of consciousness, 224; imaginary worlds in, 47; implantation in a new body of, 242-52; interaction between world and, 451; mapping of, onto bat's mind, 412; vs. matter 383, 387, 416; miracle drug to annihilate, 383: and nature of mentality, 95; “nonlin-

ear" nature of, 294; nonquantum-mechanical computational models of, 43; objective concept of, 399; origins of, 144; other (see otherminds); owning one's, 12; philosophy of, 232; physical basis of, 393; physicists' notion of, 34; plea of animal heard by, 110; processes of, 11; products of, 95; reductionist view of, 36-38; and seeing, 30; as self-perceiving pattern, 200; as sentience, 406; simulation of, 74, 78; software replicators in, 145; and soul, 107; specialization of psychologists in understanding, 67; structure of, 274; study of, and computers, 353; tampering with, 293; taping of, 243, 252; tuning of body and, 248; and Turing test, 93; ultimate nature of, 94, 457
mind-body duality, 35, 40
mind-body problem, 391, 392, 396, 397
mind's eye, 21, 141, 283, 375 mind tapes, 243-9, 252
"miminal logic," 424
Minsky, Marvin, 240, 343, 475
miracle drug, mind-annihilating, 383-84
miracles, 313, 319
mirror image, being one's own, 406
mirroring of external universe, 82
mirrors, 28, 192-93; puzzle of, 404-5, 479; self reflecting, 304, 318-19
mistakes, 48
missiles, 90
mistake-making, 89
models, 88; of civilization, 290, 293; of consciousness, 304-5; created by personoids, 310; of Creation, 315; digital and stochastic, 97; of DNA-RNA interaction, 274; of hemoglobin molecule, 125; of intentionality, 367; internal, of representational system, 193; mechanical, of world, 300; nonquantum-mechanical computational, 43
modernist writing, 461
modes of perception, 156, 157 modularity, 413
modulations, 155
molecular biology, 36, 40 molecular hoopsnakes, 458
molecules, 3, 27, 34, 39; behavior of, 34; calculation of motion of, 153; evolution of, 125; formation of, 125; genetic, 41 (see also DNA); modern, 125; random movement of, 168, 170; water, 173-74
Monod, Jacques, 120, 129
Monty Python, 276
Moon, 32; conquering of, 296; of Microminians,
294; ownership of, 5; robot society on, 257-65
moons of Mars, 3
moral responsibility, 321-24, 327, 339
morality, 42, 107, 333, 336, 339-40, 385, 420; of
mind-annihilating drug, 383-84; and suicide,383
Morowitz, Harold J., 34-47, 467, 468
Morrison, 100, 103, 104
Morse code, 76
mortal in dialogue with God, 321-41
mortality, 89
Mortensen, Chris, 477
Morton, Adam, 478
Moslems, 57
Motion and Resistance System (MARS), 234-35, 240
Moulton, Steve, 240-1
mouth, 26
mouth-directing neurons, 438
mu, 159-63, 181-83
MU-picture, 180-83
multiple personalities, 479-81
multiple stories, 47

multiple stories, 47
multivalent logic, 311
murder among personoids, 307
muscle, evolution of, 132
music: emotional responses to, 81; hearing of,379; nature of, 448, 452; stored in records, 431-33, 439, 440, 451, 452
mutation, 41, 57 myrmecologist, 163
myrmedian, 169
mystery: of God, 315; of life, 383
mysticism, 40, 83
mythology, 276

NAAD, 309-10, 313-16
Nagel, Thomas, 32, 192, 391-403, 404-14, 478, 481
native Chinese speakers, 355
natural selection, 124, 126, 129-32, 199
nature: laws of, 337-38, 341, 343; regularities in, 451; suatification of, 195
Nazis, 114 necessary time, 342
Necker cube, 221
negative feedback, 135
neobehaviorism, 399
neoevolution theory, 109
nervous disorders of ant colony, 163
nervous system, 142; continuity of, 64-65; evolution of, 304; of lobster, 266; prosthetic. 222
neural chains, 436
neural clerk, 446
neural dance, 453
neural discharges, random, 106
neural flash, 167, 436-37, 450, 452-53, 456
neural identity, 209-10
neurobiology, 42
neurological components of behavior, 36
neurons, 166, 185, 268, 377, 379; connecting hemispheres, 203-8; in Einstein book, 437, 441-43,446; feeding of experience to, 207-12; firing of, 167, 177, 194, 202, 203, 208, 342, 363, 364, 435-36; and laws of physics, 76: locality of response to stimuli of, 385; nervous impulse impinging on, 65; and perception of brain state, 282; programmed by symbols, 282
neurophysiology, 363, 369; of bats, 394, 397
neuroscience, 217, 465
neurotransmitters, 377
neutron star, 77, 145
Newell, Allen, 358, 364, 477
Newton, Isaac, 37, 42, 130
Newtonian mechanics, 145
Newtonian physics, 36
Nickles, Thomas, 472
Nietszche, Friedrich, 295, 469
Nilsson, Nils, 471
Nim Chimpsky, 470
Nirvana, 334
Nisbett, Richard, 471
nodes, 194
noise, thermal, 41
nominative case, 407-8
noncognitive subsystems, 360
non-Euclidean geometry, 374
nonquantum-mechanical computational models, 43
nonzero sum game, 312
Norman, Donald, 471, 473
nose, 26, 467
nosrep, 404
novels: meaning of 81- point of view in, 350-351; world as, 461; see also fictional charcters

novel-writing computer, 69; 350
Nozick, Robert, 461-64
nuclear particles, 145
number theory, 150-51, 187
Numbers, Ralph, 256-65, 267-68
numerical conversion tables, 439, 382
numerological mapping schemes, 382
numina, 347

object, unique relationship to itself of, 278
objectivity, 43; of nature, 120; vs. subjectivity, 395, 396, 398-9, 402, 409-11, of thinking machines, 84
Obler, Loraine K., 477
oblivion, abysses of, 292
observers, 27, 43, 281; conscious, status as, 43, 44; external, 8; interpretation by, 371; and measurement, 38, 43; mind of, 37; and relativity theory, 37; separate states for, 46
ocean waves, 125 -Lave, 163
Ojemann, George A., 193, 473
Olympic Torch, 409
omnipotence, 313 of God, 57, 316;
ominiscience, 326
ontology, 303, 463, 464; personoid, 310, 316; questions of, 466
operationalism, 93, 290, 371
opportunism of evolution, 305
opposite sex, what is it like to be?, 406
optical conversion tables, 447
order vs. chaos, 167, 168
orders of magnitude, 375
organ point, 183, 184
organic molecules, 127
organic quality of entity, 80
organisms, 199; complexity of molecules in, 125; needs of, 11
organizations, personification of, 192
origin, sameness of, 80
Orthodox Judaism, 333
Orwell, George, 386
Osgood, C. E., 480
osmosis, 307
other minds, 9-11, 13-14, 24, 32, 79; and artificial intelligence, 366; nonexistence of, 30; Taoism on, 82
otherness, 32
outside, consciousness from, 8-10
oxygen, 145, 242

pacifism, 90
pain, 8-10, 95, 240, 328, 462; and artificial intellicence, 370; in bat experience, 395; causal behaviorist analysis of, 400; as illusion, 425; punishment of evil with, 329; see also suffering
paintings, 451: static nature of, 192
palates, 114
panpsychism, 83, 381
paper, slips of, 378
parabola, 451
parabolic reflector, 141
paradoxes, 422, 425, 454; fundamental, 277; logical, 325; self-referential, 275-79
parallel processing, 318
parallel worlds, 46
paranoia: of chimpanzee, 104; computer simulation of, 91, 469
parents, body made by, 47; my essence depends on my, 468
Parkinson, K. C., 469

Parmenides, 213
parrots, 378
PARRY, 91-92, 469
Parsons, Terence,476
particle accelerator, 79
particles: altering paths of, 196; animate interplay of, 291; soul as gulf between pies and, 385; underlying laws of, 193
particulateness of genes, 133
parts: relationship of, 433; see also sums o', wholes vs. parts
Pascal, Blaise, 311
passion, 84
passive symbols, 176, 178
Pat, 69-92
path of least resistance, 436, 452, 453
patriotism, 114
Pattee, Howard H., 472
pattern oriented mechanism, 86
patterns: abstract, 78; complex, of atop 125; decoding of, 101-2; existence of, guistic, 107; of molecules, 170; of firings, 177; recognition of, 201; thou, 78
Pavlovians, 35 peace, 288
Pedersen, 243-44, 246, 248
people: grouping of atoms to manufacture, 124; as machines, 89
Pepys, Samuel, 106
perception, 8, 35, 74, 122, 213, 294, 395 in bat sonar, 394, 395; of brain state, 282; of colour 479; doubting one's own, 426; of God,:330; and imagination, 400; indirect, 76; and mirrors 192; modeling of, 282; modes of, 11, 156-57; objective description of, 402; and perceiver, 299; of personoids, 16;and reasoning, 343; relativity of, 290, 292, 297, 299, 301,:302 and self-perception, 199; shift of, 196; on symbol level, 182; visual, 467
perceptual aboutness, 406
percipi, 299
perfection: failures as product of, 287;333
Perry, John, 466, 467
Perry, Ralph Barton, 482
person, 225; duplicating, 7, 466; fusing, 466; mental image of, 21; of non-dominant hemisphere, 14; as program, 97; splitting, 466
personal identity, 4, 468; quantum mechanics and problem of, 48
personal vs. impersonal views, 335
personal location, 221, 224, 237
personal nonexistence, incomprehensibility of, 30
personality, 225; attribution of, 114;in eyes of beholder, 335; hierarchical organization of, 342; imitation of, 305; and resolution of inner conflict, 342; as style. 84
personality traits, 385
personetics, 296-317, 413
personhood, 224, 406; recognition of 76
perspective, 453; shift in, 224
phenomenalism, 301
phenomenology: bat, 395; Martian, 395; and objectivity, 396, 402-3; visual, 397
philosophical psychology, 399
philosophy, 64, 274, 317, 319, 467, 470;Eastern, 341; of the mind, 217, 232; personoid, 310; physicalist, 224; of science, 37, 93
photoelectric cells, 358
photons, 94
photosynthesis, 8, 367; simulation of, 372
physical vs. mental, 404
physical parts, person as nothing more than, 89

physical symbol system, 365
physicalism, 393, 400-4
physics, 195, 199, 301; antimatter postulated in, 388: atomic. 36; building blocks of, 6; on consciousness, 304; epistemological problems in, 414: integration of biology and psychology with, 39; laws of, 66, 142, 144, 319; materialism in, 34; mirror puzzle in, 404; on nature of space, 298; observer systems in, 44-45; twodimensional, 319
physiology, 35, 212; and behavior, 36; and origin of thought, 41
pi, 7, 151; value of, 65
Picasso, Pablo, 59, 406
pigeons, 273, 393
pigs, 114
piranhas, 114
planets: chemical raw materials present on, 126;
distant, voyages to, 142
plants as survival machines, 133
Plastic Big Hawley, 236-39
plastic surgery, 225
plate tectonics, 77
Plato, 466
plausibility, 106
playing records, see records playthings, 103
pocket calculators, 84
poetic license, 268
poetry, 319
point of view, 9, 13, 24, 25, 278, 434; of ants, 173; changing, 174; in dreams, 350; toward God, 335; levels of, 179; location of 221-24, 237; me-ness attached to, 48; and per sonetics, 301; of programmers, 355; of robot, 268; as sentience, 406; shifts in, 196; and subjective character of experience, 393, 396-99, 402, 409, 411, 413; switching, 343; and thought experiments, 376, 381; uninhabited or vacated, 268
poison, 105
polar hears, 139
polygon, philosophical, 309
pond-hole experience, 203, 204
Popper, Karl, 477
positive-negative replication, 128
potato chips, 342
Potter, Beatrix, 268
power: and knowledge, 313; of the "Word," 274; see also causal powers
precognition, 66, 68
preconscious concepts, 267 predictionism, 197
predictions: genetic, 139: through simulation, 139
preludes, 154, 190; relationship between fugues and, 154-55
Premack, David, 470
pressure, 168
Pribram, Karl, 472
primal grammar, 107
primal intuition, 335
primal loop, 283
primates: autobiographers, 460; difference from other animals of, 41: intentionality ascribed to, 365; language of, 106, 107; see also specific species
prime factors, 195
prime numbers, 387
primeval soup, 127-30, 133
primitives, talking to trees by, 335
primordial cause, 195
Prince of Wales. 387
principles, soul as gulf between particles and, 385
prism-shaped glasses, 412
privacy of experience, 396

"private 1," 281
privacy of mind. 7-9
probability, 127; in quantum mechanics, 43
probability distribution, 38
problem solving, 9, 361
process: God as, 333-34; person as, 444, 446
products that think, 70
programmer, role of, 136-37
programming: of Analytical Engine, 64; of computer by itself, 63
programs: Al, see artificial intelligence and specific
programs; of domino-chain network, 195; emulation by, 412; feelingless, 84; mind as, 243;operating in parallel, 363; person as, 97; inpersonetics, 299. 300, 307; point of view of, 410, 411; read out of brains, 252; redesigners of computers, 252; representational, 193;rigid, extinction of, 200; self-model absent in, 82; self-monitoring abilities of, 282; self understanding abilities of, 282; trust of protoplasm in, 112; Turing tests of, 90; see also simulation
project, 120
projection, 114, 115, 374, 413; language as medium of, 413-14; see also mapping
pronoun' he," 443
proofs, 94-95; of existence of God, 315; of theorems, 151, 153
properties: emergent, 145; on other levels, 84; of wholes vs. parts, 144
propositional content, 362
Prospero, 464
prosthetic vision, 231, 411, 475
proteins, 35, 88, 125; synthesis of, 139
proto-carnivores, 131
protoplasm, 112
Proust, Marcel, 69
psyche, 305; influence of sensory deprivation on,306; scientific observation of, 42 psychiatrists: atheism of, 330; fooled by computer, 91, 469
psychic distancing, 221
psychics, 195
psychoanalysts, 480
psychokinesis,66
psycholinguistics, 14, 273
psychology, 34; AI as branch of, 361; extrasensory perception disputed by, 67; integration of biology and physics with, 39; introspective,369; life as experiment in, 32; philosophical, 399; physiological, 35
psechonics, 297
psvchophagi, 308 psychopathology,12
psvchophvsical theory, 391, 398, 401
Pucceti, Roland, 478
pulsars, 77
punishment: eternal, 383; for sins, 322, 324
purines, 127
purpose, 120
"purpose machine," 135
purposeful behavior, 172-74
purposiveness, 122, 191, 386
purring machine, 111, 112
Putnam, Hilary, 231n, 474-75, 478
Pvlshyn, Zenon. 360. 374
pyrimidines, 127

quantum electrodynamics, 145
quantum field theory, 145
quantum mechanics, 36-39, 41, 42, 48, 49, 167;many worlds interpretation of, 46. 458: of oxygen atom, 145

"quantum water faucet," 43
quarks, 458
question, unasking of, 162
Quine, Willard V. 0., 466

rabbits, 121, 268
radio: brain linked to body by, 218, 459; brain hemispheres connected by, 205-7; communication via, 137-38
radioactive decay, 38
random choices, 48
random events, 38
random number generator, 67
randomness, 106, 115, 166; of ants, 170, 172; of molecules, 168
rain drops, 124
rainstorms: information processing by, 371; simulation of, 370
Raphael, Bertram, 471, 476
rationality, 306, 477
readout of brain, 282
real world, interpretation of, 300
realism, 39, 107
reality, 456; bifurcation of, 338; consciousness as ultimate, 39; physical, 37; representation and, 94; of superpositions, 44
realization, distinction between program and, 369, 372
reason, 23; emotions at odds with, 305
reasoning, 343
rebirth, 244
recognition, 9
recombinant DNA, 271
records, 149, 431-33, 439, 440, 448-52
Red King, 349
reducibility of experience, objection to, 399
reductholism, 190
reductio ad absurdum, 76, 212, 458-9
reductionism, 35, 40112, 93, 144, 159-62, 182, 190, 196-97, 391-93, 397-99,472,473, 478; vs. holism, 162; physiological and biological, 3637; translatability of holism and, 196
reflection, 193
reincarnation, 5
relativity: of perceptions, 74, 290, 292, 297, 299, 301, 302; theory of, 37, 145, 196; of time scales, 145
religion, 334, 341 repertoire, innate, 31 replication, 113
replicators, 127-31; cultural, 143-44; software, 145; survival of, 122
representation, 94; internal display of, 266; ofknowledge in ant colony, 170 representational power, 199
representational systems, 192, 281, 379, 382, 411, 473; of bats, 412; relationship between facts and, 396; of soul-free objects, 386
repression, 12
reproduction, 8
reproductive act, 109
Reps, Paul, 45, 467
"Reset" button, 295
resistance of axons, 435
restaurants, stories about, 354, 359
retarded people, 107
retroactive causality, 197
revelation, 311
reverberation, 437
revolution, 342; in scientific world view, 68
rewards, 107
Riddle of the Universe, 269-76
"right stuff." 365 497

right and wrong, distinction between, 339-40
Ringle, Martin, 471, 477
Rip Van Winkle, 482
ripples, 44
rivers, 120
RNA, 274, 458
Robbins, Tom, 295
robots, 87, 96, 471; and artificial intelligence, 362-65; autonomous, 255-65; canned sentences intoned by, 92; computer control of, 21; computers dreaming they are, 318; consciousness of, 8-10, 13: functional and intentional states of, 392; of oneself, 234-41; point of view of, 268; programmed for self-preservation, 123; self-protective, 266
rocks, 125; attribution of intention to, 120; molded by free play of physical forces, 120
Rokeach, Milton, 482
romanticism, II "rooms" of brain, 452
Rorty, Amelie 0., 393, 466, 473, 474
Rorty, Richard, 478
Rosenblith, W., 473
Rosser, J. B., 58
rotating frame, 196
"round one," 441 R2D2, 87
Rucker, Rudy, 253-68
rules of behavior, 65-66
Rumbaugh, Duane, 470
Rumelhart, David, 473
rumors, 287
rusty hinges, oiling of, 453
ruthlessness of spirit, 120

Saccheri, Gerolamo, 374
Sacks, Oliver, 482
sadness, simulation of, 83
Sagan, Carl, 35, 39
Sainter, 299
saints, difference between sinners and, 333
Salinger, J. D., 406
salt crystals, 125
salvation, 328, 332, 334
Sanborn, Mr., 426-29
Sands, Matthew, 467
Sandy, 69-92
Sanford, David Hawley, 231, 232-41, 475
Santa Claus, 4, 256
Satori, 276
Saunders, M. D., 481
Savage, C. Wade, 471
Savage-Rumbaugh, Sue, 470
Savodnick, I., 472
scale, narrative problem of, 459
"scattering" questions off target mind, 79 scent, 121
Schank, Roger, 354-56, 358, 367, 362-63, 373, 469, 473, 477
Schopenhauer, Arthur, 42
Schreiber, Flora Rheta, 479
Schrodinger, Erwin, 38, 45
.Schrodinger s cat, 38, 45, 46
science, 7, 31, 319, 457; and accounts of consciousness, 11; extending familiar concepts,77; hard, rigorous methods of, 460; materialism in, 34; philosophy of, 37, 93; secrets revealed by, 8; and spirit, 122; as storytelling, 460
science fiction, 74, 465
scientific induction, 61, 63
scientific method, 120
scientific world view, 6; revolution in, 68
Scriabin, Alexander, 455

scribes, 128
Scriptures, 383, 462
sculpted forms, grooves of records as, 433
sea: acoustics of, 138; of possibilities, 42
Searle, John R., 93, 94, 268, 352, 353-82, 384, 387, 407, 477
Searle's demon, 376, 378, 380
seaslugs, 10
seeing, 6, 30; two distinct types of, 32
self, 5, 466, 467; belief in, 7; as by-product of organism, 167; continuity of, 410; and control, 268, 453; inhabiting body, 24; interlevel feedback in creation of, 279; and mirror-image, 28; and otherness, 32; process of creation of, 352; riddles of, 458; as sentience, 406; thinking about, 20-22, 467
self-awareness, 182, 447
self-consciousness, 11, 182, 266-67, 340; capacity of machines for, 61, 63; in chimpanzees, 471; self-regarding behavior without, 266; of spirit, 122
self-contradictory belief system, 277
self-deception, 29
self-defense, 12
self-destructive tendencies, 305 s
elf-engulfing television system, 279, 281
selfhood, 266
self-image: introspective, 41; pattern of, on TVscreen, 281; of soul-free objects, 386
selfishness, 4, 142, 228
self-model, 82, 83
self-organizing processes, 291; of mind, 294
self-perception, 29, 199
self-portrait, 86
self-preservation, 131
self-recognition, 19, 28
self-reference, 92, 181, 475; indirect, 184; looplike, 279; parameters of, 281
self-referential paradoxes, 275-79, 475
self-reflecting mirrors, 304
self-regard, 266, 268
self-reliance of computers, 87
self-replicating systems, 41
self-representation, 21
self-reproductive power, 113
self symbol, 200, 264-67, 413
selves, multiple, 12
semantic differentials, 480
semantic level of processing, 15
semantic potential, 196
semantics, 375, 406; computers' lack of, 368, 370
semiautonomous subsystems, 200
Seng-Ts'an, 339
senility, 107, 248, 409
sensations, 8, 26, 122
senses: God as, 330; human, 394; see also hearing; perception; vision
sensory deprivation, 306
sensory input messages, 167
sensory modalities, 11, equivalence of, 411, 433
sentences: comprehension of, 14; constructed bypersonoids, 302; identity-asserting, 408
sentience, creation of, 297
Septuagint, 128
sequence of neural firing, 363
servo-control, 111, 141
Seuss, Dr., 78
sex, true nature of, 114
sex-change operations, 225
sex-role differences, 72
sexual reproduction, 132; and personetics, 309
sexuality, 250
shadows: confusion of reality and, 77; formal. 367
Shakespeare, William, 382, 462, 464

"Shakey," 21-22
"she loves me, she loves me not," 47
Shoemaker, Sydney, 474
short-term memory, 410
shortwave radio, 76
SHRDLU, 317, 354, 475
Siamese twins, 406
Sigma-5 computer, 380, 412
signals, 171-72, 176, 177, 180, 199; purposefulness of, 174
signs, linguistic, 107
Simon, Herbert, 358, 471, 472, 477
simplicity, 124
simulated worlds, 317-18, 476; see also personetics
simulation, 87, 94, 139-42, 145; of ability to use language, 294; of bat experience, 414; of chemical conditions of Earth before life, 126-27; of cognitive capacities, 353 (see also artificial intelligence); of complex behavior, 73; confusion ofreality and, 73; of cow, 94, 372; of death, 308; duplication distinguished from, 369-71: emulation distinguished from, 380, 477; of hurricane, 73-78; of interacting molecules, 145; oflactation or photosynthesis, 372; of Middle Ages, 97; of paranoid, 91; of primordial light ning, 126; of sadness, 83; of sensory perception, 234; of thought, 73; time needed to run, 318, 459; of a world, 476
sinning, 321-25, 327-29, 336, 339, 341
641 (prime number), 194, 387
size of simulation, 376
skepticism, 27-28; about artificial intelligence, 69; about Fermat's Last Theorem, 150-51 skill, 246
skintact, 233-34
slaughter, random, 115
slaughterhouses, 114
sleep, 9
slipperiness, biological, 89
Slobodkin, Lawrence B., 41
Sloman, Aaron, 201, 473
Slote, Michael, 476 slugs, 121
small-souled men, 107 Smart, J. J. C., 478
"smart bullets," 90
Smullyan, Raymond, 92, 265, 321-40, 340-43, 383-84, 384-88, 415-26, 427-29, 467, 479
Smythies, J. R., 473
soap bubbles, 125
Sober, Elliott, 472 social behavior, 34
social processes, large-scale, 302
socialization, 302 sociobiology, 37, 40
sociodynamics, 303
sociology, 140
Socrates, 31, 144 S
Socratic method, 326
sodium channels, 193-94
sodium ions, 125
software, 80, 89; mind as. 243; preservation of, 261; replicators of, 145; see also programs software universe, see personetics
solar energy, 260, 262
solar system, 126; clockwork, 122
solids, 145
solipsism, 60, 61, 83, 400, 456; on human condition, 30-32
sonar, 141; of bats. 393, 395, 402; of blind people, 397
song, mentality like a, 95; simulated, 97, 99
"Sonic Oven," 275
sonnet-writing machine, 60

soul, 5, 25, 32; attribution of, 114; in book, 450; brain as physical seat of, 220; collapse of two souls into one, 407; of cow, 386; dualistic no tion of, 381; exhaustion of, 345; flamelike notion of, 408-9; and free will, 454; greater than hum of its parts, 191; of hurricane, 75; immateriality of, 224; as incompressible core,385; interlevel feedback in creation of, 279, 281; and mind, 107; miracle drug to annihilate, 383, 384, 386; nature of, 385; as neural dance, 453; of personoids, 303, 306, 317, 318; of a prince, 465; and self-reproductive power, 113; as sentience, 406; and spirit, 121; thinking as function of, 57; transmigration of, 5; true seat of, 233
soul-breaking, 386
soul-killing, 114
soul meter, 107
soul searching, 4, 47
soulism, 197
sound, 438; of words, 456; as wave phenomenon, 141, 399
sow. offspring crushed to death by, 110
space: curved, 458; different size-scales in, 197; discrete, 319; locality in, 319, 385; minusculecapering of electrons in, 291; movement of object through, 282; nature of, 298
spacecraft, 125
space-time continuum, 327
spatial proximity, 449
specialization, 169, 171
species-specific viewpoint, 398, 399
speech center, neutral activity of, 101
speech impairment of ant colony, 163-64
speech neurons, 442
speech organs, 438
SPEECHIAC, 351
speed of operations, 376
spelling, 266
Sperry, R. W., 472
spiders, 9
Spinoza, Baruch, 19
spiral galaxies, 122, 145
spirit, 4, 119-22
split-brain research, 14-15, 481
split characters, 47 split self, 47
Spoilar, 209-12
spontaneity, 120 s
portscasters, 31
squid, 121
squiggles and squoggles, 359-60; of Chinese, 378; meaningless, 378
SRI International, 21
stability, 125-26
Sta-Hi, 257
starquakes, 77
stars, 125
states, 178, 193; superpositions of, 193; see also brain states; mental states
statistics, 168; regularity of, 166
steam shovels, 86
steel hammer, 112
Steiner, George, 414, 477
stimulus, 114
stomachs, information processing by, 360, 371
Stonehenge, 382
stories, capacity to understand, 254-60, 363, 369, 370, 373
storytelling and science, 460
"strange loops," 475
stratification, 195, 199
Stratton, G. M.. 475
Strawson, Peter, 249
Stretto of fugue, 164-65

strong A1, 353, 361, 366
structural integrity, 449-50
structure-altering numbers, 437 s
stuff, 375; mental and physical, 387
style, individual, 385
subatomic collisions, 291
subconscious, 156, 158; biases of, 84; and creativity, 283
subject, 406; duality of object and, 25; fluctuation
between object and, 33
subjectivity, 43, 478; of experience, 392-93, 39596, 402-3, 409-14; imputed to animals, 134;and quantum physics, 46; of time experience, 302
sublimation, 282
subliminal appeals, 113
subminds, 14
subpersonal information processing system,233, 237
subpersons, 342
subsystems of brain, 13, 14; active, 176; free will of, 341-42; of God, 48; rival, 201; semiautonomous, 200; understanding in, 359
Subtillion, 96, 98
Suci, G. J., 480
suffering, 328, 462; creation of, 291, 292, 294; end to, by annihilation of soul, 384; evil as, 333; sinning as cause of, 336
sugar, 372
suicide, 90, 383
sums of parts, 144-45, 187, 432
Sun, 120, 458; setting, 47;
stability of atoms in, 125
sunlight, 126
super-ego, 12
Superman, 388
superposition of states, 43-44, 46, 47, 193
Supersonic Tunneling Underground Device (STUD), 217, 226
surprises, 155
survival: of fittest, 124; of stable, 124
survival machines, 122, 131-34, 137, 140, 141, 458
swans, 340
Swanson, J. W., 478
swirling, style of, 79
Swiss cheese, 381
syllogisms, 30-31
symbolic imagination, 400
symbolic logic, s424
symbols, 176-84, 192, 193, 200, 281; active, 265; manipulation of, 76, 107, 180, 355-56, 359,361-65, 368, 370, 372, 373, 377; modification of, 412; musical, 433; nonreflexive, 200; in number theory, 187-88; programming of neurons by, 282; vs. signals, 177-78; triggering patterns of, 177-81, 380, 413; that understand themselves, 458
symmetry: external, of body, 404; of "to be," 407-8
sympathetic imagination, 400
sympathy, 106
symphony, existence of, 6
symptoms of consciousness, 10
synapses, 35, 377, 378; coding of high-level goals into, 385; sequence of, 367; simulated, 363, 364; systematic changes in structures of, 282
synchronization, condition of, 207-10
synergy, 89
synonyms, 114
syntax, 106, 375, 406; of beliefs, 369; of computers, 368, 370; of personoids, 302; simple minded, 108
systems creation, 298

systems theory, 358-62, 374, 377
Szechuan food, 428

tactile perception, 234
talking to God, 330-31
Tammer, 304
Tannenbaum, Andrew, 380, 477
Tannenbaum, P. H., 480
Taoism, 82, 330, 333, 338, 341, 467 tapes, mind, 243-9, 252
Tapscott, B. L., 476
target-tracking computers, 90
taste, 427-28
"team" of ants, 168, 171
technology, 3, 207; and artificial intelligence, 366-67; of information processing, 299; runaway, 275; survival-machine, 132; telepresence,240; for transferring information between different brains, 252
teddy bears, 114
Teleclone Mark V teleporter, 7
Teleclone Mark IV teleporter, 3-4, 7
telekinesis, 68
teleology, 83, 120, 122, 172, 174, 196, 197
telepathy, 66-67, 307
telephones, 361-62;
time service, 378
teleporter, 3-4, 7
telepresence, 240, 475
television, 193, 212-13, 447-48; closed-circuit, 20; interlevel feedback on, 279, 281; seeing oneself on, 266; in simulation of vision, 411
temperature, 168
template, replicator as, 127, 128
tempo, 155
Terrace, Herbert, 470
terrorism, 192, 386
Terry, 242, 243, 245, 246, 248
tesseract, 298
TEX, 259-61
Thatcher, R. W., 466
Thaumaturge, 96, 99
theodicy, 309, 311, 312, 314, 316
theogony, 300, 314; experimental, 296
theology. 312; liberation of science from, 42; objection to thinking machines in, 57-58
thermodynamics, 39, 308
thermostats, 358, 371; beliefs of, 361
Thigpen, Corbett H., 479
thing: "it is like something to be," 13, 478; as stable collection of atoms, 124; see also BATs
thinking, 4, 6; about one's self, 20-22, 467; by dogs, 32; impossibility of stopping, 25; and feeling, 81; emotions as automatic side effects of, 81; by machines, 53-67, 70. 84, 368, 372 (see also artificial intelligence); and organization of entity, 80; in second language, 379, 477; as sentience,406; test for, 80
third-person perspective, 20, 30
Thomas, Dylan, 115
Thomas, St., 57, 336
Thoreau, Henry David, 203
thornbush, 125
Thornton, M. T., 478
thought, 35, 39; appearance and character of, 42; awareness of, 181; capacity for, 21; imitation of, 305; influence on electron of, 195; language of, 274; and machines, 60, 110; mechanisms of, 196; and neural flash, 452; origin of, 41; as pattern. 78; personoid, 302; and point of view, 221; as primary. 39; production of, 13; simulation of, 73, 77; and spirit, 120
thought experiments, 8, 375, 458, 459, 479
thread, thickening at end of, 119

thresholds, 167, 171, 435-36
thrills, 155
thrown grapefruit, 451
thunder, 126
time, 38, 42; dimension of, 297, 310; discrete, 319; before evolution, 124; locality in, 319, 385; manipulation of, 316, 318; movement of object through, 282; and prediction, 197; subjectivity of experience of, 302
time scales: relativity of, 145; varying, 174, 441, 446
time-varying intelligence, 409 Tin Woodman, 237
"tinklers," 198
title of this book, 408
toilet paper and small stones, computer constructed of, 369
top-down control, 342
topology, 207-9, 274
Tortoise, 149-91, 195; in Jardin du Luxembourg, 430-57
Tortoise's song, 452
total self-knowledge, 454
toxicological assays, 271
*toy worlds," 476
transfinite numbers, 396
transitive verb, 408
translations, 99; perversion of meaning in, 128
transmigration of souls, 5
transparency of mind to itself, I I
trees: talking to, 335, 339; see also forest triangles, equilateral, 336
triggering patterns of symbols, 177-81, 380,
413
tropism, 121
true love, 404
Trurl, 287-94
truth, 331; of expressible propositions, 396; of mental states, 358n
TSR cones, 411-12
Ts'ui P6n, 42
tuning, 247-48
Turing, Alan M., 53-67, 67-71, 377, 379, 469 70
Turing machine, 274, 276, 354
Turing test, 69-95, 107, 115, 306, 360, 371, 373, 375, 376, 378, 409, 469
Tweedledee, 349
Tweedledum, 349-50
"Twin Earth" thought experiment, 231, 474-5
two-dimensional physics, 319
typewriters, 371; nonfunctioning, 144
tyrants, 339

Ullman, Shimon, 467
ultimate perfection, 333
ultraviolet light, 126, 127
unconscious concepts, 267
unconscious processes, 9. 12-15; and neural firing patterns, 386; in scientific induction, 61;sublimation of conscious activity into, 282
unconscious purposive behavior, 135
understanding, 400; of jokes, 80; of language, 405; nature of, 353-63, 368-70, 374, 377, 378, 381
uninterpreted formal symbols, 355-56
unitary feeling of self, 48
universal machines, 56
universal wave function, 46, 48; collapse of, 48
universe, 287, 34 1; arcana of, 347;author of, 462, 463; beginning of, 124, 125; boundryless, 343; chaotic. 343: creation of new. 327: cybernetic.

318; electron composing whole, 318; five-dayold, 231; and laws of physics. 142; mechanical models of. 34; mechanistic interpretation of, 300; mystical view of, 38; radio communication with 137-38; soul-free, 386; soul meriting participation in, 345; as uniform dispersion of matter, 120
nsayable and unthinkable, doctrines of, 274
updating. 170, 181
upward causality, 197, 343
utilitarianism,. 328. 333, 336

vacuum, problem of, 145
van Inwagen, Peter, 476
varying time scales, 318, 441, 446
vegetarians, 114
Vendler, Zeno, 478
verificationism, 93
vicarious experience, 414
vicarious trial and error, 140
vicious circle, 194
Viet Nam war, 114
virgin, Greek word for, 128
virtual machines, 380
viruses, 113, 121
vision, 25, 394, 397; of computers, 87, 193; prosthetic, 411, 475
visual cortex, 231
vitalism, 36
vivisectionists, 309
vocal-cord-directing neuron. 438
voice, 76; echoic hearing of own, 222
voice synthesizer, 102
voices: existence of, 6, 466; of fugue, 155-59, 165, 183, 190; visual, of ant fugue, 175
volcanoes, 120, 126
volition, see free will volume. 168
Vulcan, 264-65

Wagstaff, 258-64
wake of boat, 44, 437
Walton, Kendall, 476
wanting, 120
war. 288
Warrington, E. K., 481
water, 126; boiling, 173; properties of, 144, 145; stable form of, for spacecraft, 125
water-H20 problem, 391
water pipe simulation of brain. 363-64, 369
Watt governor, 135
wave function, 45, 48
wave-function, universal, 48
waves, movement of, 172
Way of Nature, 340
weak Al, 353
weather prediction programs. 88
Wbb Judson, 470, 475

Wechselmann, Dr., 221
Weiskrantz, L., 481
Weizenbaum, Joseph, 354, 369, 469, 471
Well-Tempered Clavier (Bach), 154-55,185, 190
Weltanschauung of bats, 412
whales, 393
"What is it like to be X?," 301, 391-414
Wheeler, John Archibald, 213, 318, 45
Wheeler, William Morton, 472
Wheelis, Allen, 119-22, 122-23
Whitely, C. H., 277-78, 475
Whitely's sentence, 277, 278
Whitman, Walt, 341
whole-brain experience, 205-6
wholes vs. parts, 89, 144-45, 158, 162,
Wiener, Norbert, 297
Wigner, Eugene, 39, 467
Wilensky, Robert, 373 will, 120; see also free wilt
William the Conqueror, 144
Williams, Bernard, 466
Williams, G C 144
Wilson, Edward 0., 472
Wilson, Timothy De Camp, 471
Wimsatt, William, 472 wind chimes, 197-99
Winer, Deborah, 481
Winograd, Terry, 317, 354, 373, 475,
Winston, Patrick Henry, 471, 473
Wolf, Susan, 476
woman in imitation game, 71-72
Woodfield, Andrew, 468
Woodruff, Guy, 470
woods, see forest
Wooldridge, Dean, 472
words: arbitrary juxtapositions of, 106 articulation of concepts in, 282; groping for, 163; vs. letters, 177-79; mapping real world onto. 179; meaning of, 128, 428, 455-56; proper ways of using, 196; as tools, 130
worldline, 282-83
Worms, Austin, 242-46, 249
written musical scores, 433
"wrong stuff," 369

Yorick, 220-21, 226-33, 236, 238
Young, J. Z., 139
young woman, Hebrew word for, 128

Zen Buddhism, 45, 339, 467; state of satori in 276; unasking the question in, 162
Zend, 344
Zeno, 444, 457
Zipperupus,96-98
zombies, 13
Zuboff, Arnold, 202-12, 212-13, 374,
Zukav. Gary. 38

Chapter 27: Fiction

2007-02-14T06:02:00.000-08:00

I am a fictional character. However, you would be in error to smile smugly, feeling ontologically superior. For you are a fictional character too. All my readers are except one who is, properly, not reader but author.
I am a fictional character; this is not, however, a work of fiction, no more so than any other work you've ever read. It is not a modernist work that self-consciously says it's a work of fiction, nor one even more tricky that denies its fictional status. We all are familiar with such works and know how to deal with them, how to frame them so that nothing the author says-nothing the first person voices even in an afterword or in something headed "author's note"-can convince us that anyone is speaking seriously, non-fictionally in his own first person.
All the more severe is my own problem of informing you that this very piece you are reading is a work of non-fiction, yet we are fictional characters, nevertheless. Within this world of fiction we inhabit, this writing is non-fictional, although in a wider sense, encased as it is in a work of fiction, it too can only be a fiction.
Think of our world as a novel in which you yourself are a character. Is there any way to tell what our author is like? Perhaps. If this is a work in which the author expresses himself, we can draw inferences about his facets, while noting that each such inference we draw will be written by

"Fiction" by Robert Nozick appeared in Ploughshares, vol. 6, no. 3, Fall 1980. Copyright © 1980 by Ploughshares.

him. And if he writes that we find a particular inference plausible or vali who are we to argue?
One sacred scripture in the novel we inhabit says that the author our universe created things merely by speaking, by saying "Let there ..." The only thing mere speaking can create, we know, is a story, a pla an epic poem, a fiction. Where we live is created by and in words: uni-verse.
Recall what is known as the problem of evil: why does a good treat allow evil in the world, evil he knows of and can prevent? However, when an author includes monstrous deeds-pain and suffering-in his work does this cast any special doubt upon his goodness? Is an author callous who puts his characters through hardships? Not if the characters do n suffer them really. But don't they? Wasn't Hamlet's father really killed (Or was he merely hiding to see how Hamlet would respond?) Lear really was cast adrift-he didn't just dream this. Macbeth, on the other hand did not see a real dagger. But these characters aren't real and never were so there was no suffering outside of the world of the work, no real suffering in the author's own world, and so in his creating, the author was no cruel. (Yet why is it cruel only when he creates suffering in his own world Would it be perfectly all right for lago to create misery in our world
"What!" you say, "we don't really undergo suffering? Why it's as re to us as Oedipus' is to him." Precisely as real. "But can't' you prove that you really exist?" If Shakespeare had Hamlet say "I think, therefore I am, would that prove to us that Hamlet exists? Should it prove that to Hamlet and if so what is such a proof worth? Could not any proof be written into a work of fiction and be presented by one of the characters, perhaps on named "Descartes"? (Such a character should worry less that he's dreaming, more that he's dreamed.)
Often, people discover anomalies in the world, facts that just don jibe. The deeper dug, the more puzzles found-far-fetched coincidences dangling facts-on these feed conspiracy and assassination buffs. That number of hours spent probing into anything might produce anomalies however, if reality is not as coherent as we thought, if it is not real. Are we simply discovering the limits of the details the author worked out? Bu who is discovering this? The author who writes our discoveries knows them himself. Perhaps he now is preparing to correct them. Do we live, in galley proofs in the process of being corrected? Are we living in a first draft?
My tendency, I admit, is to want to revolt, to conspire along with the rest of you to overthrow our author or to make our positions more equal, at least, to hide some portion of our lives from him-to gain a little breathing space. Yet these words I write he reads, my secret thoughts and

modulations of feeling he knows and records, my Jamesian author.
But does he control it all? Or does our author, through writing, learn about his characters and from them? Is he surprised by what he finds us doing and thinking? When we feel we freely think or act on our own, is this merely a description he has written in for us, or does he find it to be true of us, his characters, and therefore write it? Does our leeway and privacy reside in this, that there are some implications of his work that he hasn't yet worked out, some things he has not thought of which nevertheless are true in the world he has created, so that there are actions and thoughts of ours that elude his ken? (Must we therefore speak in code?) Or is he only ignorant of what we would do or say in some other circumstances, so that our independence lies only in the subjunctive realm?
Does this way madness lie? Or enlightenment?
Our author, we know, is outside our realm, yet he may not be free of our problems. Does he wonder too whether he is a character in a work of fiction, whether his writing our universe is a play within a play? Does he have me write this work and especially this very paragraph in order to express his own concerns?
It would be nice for us if our author too is a fictional character and this fictional world he made describes (that being no coincidence) the actual world inhabited by his author, the one who created him. We then would be fictional characters who, unbeknownst to our own author although not to his, correspond to real people. (Is that why we are so true to life?)
Must there be a top-floor somewhere, a world that itself is not created in someone else's fiction? Or can the hierarchy go on infinitely? Are circles excluded, even quite narrow ones where a character of one world creates another fictional world wherein a character creates the first world? Might the circle get narrower, still?
Various theories have described our world as less real than another, even as an illusion. The idea of our having this inferior ontological status takes some getting used to, however. It may help if we approach our situation as literary critics and ask the genre of our universe, whether tragedy, farce, or theater-of-the-absurd? What is the plot line, and which act are we in?
Still, our status may bring some compensations, as, for example, that we live on even after we die, preserved permanently in the work of fiction. Or if not permanently, at least for as long as our book lasts. May we hope to inhabit an enduring masterpiece rather than a quickly remaindered book?
Moreover, though in some sense it might be false, in another

wouldn't it be true for Hamlet to say, "I am Shakespeare"? What do Macbeth, Banquo, Desdemona, and Prospero have in common? The consciousness of the one author, Shakespeare, which underlies and infuses each of them. (So too, there is the brotherhood of man.) Playing on the intricacy both of our ontological status and of the first person reflexive pronoun, each of us too may truly say, "I am the author."

Note From the Author

Suppose I now tell you that the preceding was a work of fiction an the "I" didn't refer to me, the author, but to a first person character. 0 suppose I tell you that it was not a work of fiction but a playful, and so of course serious, philosophical essay by me, Robert Nozick, (Not the Robert Nozick named as author at the beginning of this work-he ma be, for all we know, another literary persona-but the one who attended P.S. 165.) How would your response to this whole work differ depending on which I say, supposing you were willing, as you won't be, simply to accept my statement?
May I decide which to say, fiction or philosophical essay, only now, as I finish writing this, and how will that decision affect the character of what already was set down previously? May I postpone the decision further, perhaps until after you have read this, fixing its status and genre only then?
Perhaps God has not decided yet whether he has created, in this world, a fictional world or a real one. Is the Day of Judgment the day he will decide? Yet what additional thing depends upon which way he decides-what would either decision add to our situation or subtract from it?
And which decision do you hope for?

Robert Nozick

Chapter 26: A Conversation with Einstein’s Brain

2007-02-14T06:01:00.000-08:00

The Tortoise and Achilles bump into each other accidentally at the edge of one of the large octagonal ponds in the fardin du Luxembourg in Paris, where young lads and lasses often take their small sailboats-and, in this day and age, even motorized and radio-controlled boats. But this is beside the point. It is a pleasant fall day.

ACHILLES: Why, Mr. Tortoise! I thought you were back in the fifth century B.C.!
TORTOISE: What about yourself? As for me, I often stroll through the centuries. It's good for the spleen, and besides, I find it refreshing on a pleasant fall day to meander among the bushes and trees, watching children grow old and die, only to be supplanted by a new generation of equally brainless, but generally rambunctious, human beings. Ah, what a harried existence it must be, to be a member of that feeble-minded species. Oh-pardon me! Indeed, I totally forgot I was addressing a member of that noble race. Why, you, Achilles, of course are an exception to the rule (thereby proving it, as the common human "logic" has it). You have been known, on occasion, to come out with truly insightful comments about the human condition (even if they were, to some extent, more or less accidental and unintended!). I feel very privileged to have known you, of all the human race, Achilles.

ACHILLES: Why, how kind of you to say those things about me. I'm sure I hardly deserve them. But, getting back to our chance meeting, I happen to be here today to have some footraces with a friend. However, he did not show up, so I am led to guess that he had sized up his chances and decided to spend his day some more profitable way. So here I am with nothing particular to occupy me, a leisurely day ahead of me to stroll about, watching the people (and Tortoises), and musing on philosophical matters, which, as you know, is a hobby of mine.
TORTOISE: Ah, yes. As a matter of fact, I too have been musing somewhat over some somewhat amusing ideas. Perhaps you'd like me to share them with you?
ACHILLES: Oh, I should be delighted. That is, I should be delighted as long as you're not going to try to snare me in one of your wicked traps of logic, Mr. T.
TORTOISE: Wicked traps? Oh, you do me wrong. Would I do anything wicked? I'm a peaceful soul, bothering nobody and leading a gentle, herbivorous life. And my thoughts merely drift among the oddities and quirks of how things are (as I see them). I, humble observer of phenomena, plod along and puff my silly words into the air rather unspectacularly, I am afraid. But to reassure you about my intentions, I was only planning to speak of brains and minds this fine day -and as you know, of course those things have nothing-nothing whatsoever-to do with logic!
ACHILLES: Your words do reassure me, Mr. T. And, in fact, my curiosity is quite piqued; I would certainly like to listen to what you have to say, even if it is unspectacular.
TORTOISE: You're a tolerant soul, Achilles-a praiseworthy way to be. Well, we're about to broach a difficult subject, so I will ease us gently into the waters by means of an analogy. You are familiar with "playing-records," aren't you-the kind of grooved plastic platters upon which are imprinted fine, near-microscopic patterns?
ACHILLES: Indeed I am. Music is stored upon them.
TORTOISE: Music? I thought music was something to listen to.
ACHILLES: Yes, it is, to be sure. But one can listen to playing-records.
TORTOISE: I suppose. If you put them up next to your ear. But they must make awfully silent music.
ACHILLES: Oh, surely, Mr. T, you are joking. Haven't you ever listened to the music stored upon a playing-record?

TORTOISE: To tell the truth, I have been inspired, at times, upon gl ing at some playing-records, to hum tunes. Is that it?
ACHILLES: Hardly. You see, you put them on a rotating turntable a place a thin needle, which is affixed within a long arm, in the out most groove, and-well, the details are too much for me, but the en result is that you hear the glorious sounds of music coming out a device called a loudspeaker.
TORTOISE: I see, yet I don't see; why don't you just use the loudspeaker and dispense with the other paraphernalia?
ACHILLES: No-you see, the music is not stored in the loudspeaker; it is in the record.
TORTOISE: In the record? But the record is there all at once; music, as f know it, comes slowly, a bit at a time. Isn't that so?
ACHILLES: You are right on both counts. But even though the record is there "all at once," as you put it, we can draw sounds out of it bi by bit. The idea behind this is that the grooves pass slowly under the needle, and as they pass, the needle vibrates slightly in response to those very fine designs you earlier referred to. Somehow, in those designs are coded musical sounds, which are processed and passed on to the loudspeaker, to dispense to our waiting ears. Thus we manage to hear the music just as you said, "a bit at a time." The whole process is quite marvelous, I should say.
TORTOISE: Well, it is marvelously complicated, I'll grant you that. But why don't you do as I do just hang the record up on your wall and enjoy its beauty all at once, instead of in small pieces doled out ove a period of time? Is it that somehow there is a masochistic pleasure in the pain of doling out its beauties so slowly? I am always against masochism.
ACHILLES: Oh, you have totally misunderstood the nature of music, I am afraid. You see, it is in the nature of music to be spread out over a period of time. One doesn't just enjoy it in one sudden burst of sound-it can't be done, you see.
TORTOISE: Well, I suppose one wouldn't like hearing one large piercing noise-the sum of all the parts-in one short blow. But why can't you humans do as I do-it's such a simple, obvious idea-hang the playing-record up on your wall and, with your eyes, take in all its pleasures at a glance! After all, they are all there, aren't they?
ACHILLES: I am astonished to hear that you find the surface of one playing-record any different from that of any other. They all look alike to me-much as Tortoises do.

TORTOISE: Well! I hardly need dignify that comment with an answer. You know very well that they are just as different as, say, two pieces of music, one by Bach and the other by Beethoven.
ACHILLES: They look very similar to me.
TORTOISE: Well, it was you who allowed as how the very surfaces of the record contain all the music-thus if the two pieces of music differ so must the record surfaces differ-and to exactly the same amount as do the pieces, moreover.
ACHILLES: I guess you've got a point there.
TORTOISE: I'm glad you'll grant me that. So, since all of the music is on the face of the record, why don't you take it in at a glance, or at most a cursory once-over? It would certainly provide a much more intense pleasure. And you'll have to grant that each part of the musical selection is in its proper place; the relationship of the parts is not lost, as it would be if all the sounds were to be heard at once.
ACHILLES: Well, in the first place, Mr. T, I don't happen to have very good eyes, and
TORTOISE: Aha! I've got another solution! Why don't you paste all the pages of the written score of some selection upon your wall and regard its beauties from time' to time, as you would a painting? Sure you'll have to admit that the music is all there, in every last respect.
ACHILLES: Well, to tell the truth, Mr. T, I must confess to a shortcoming in my aesthetic capacities: I doubt that I would know how to visually interpret the printed symbols in front of me in such a way as to give me the same pleasure as I gain from the actual hearing.
TORTOISE: I am sorry indeed to hear that. Why, it could save you so much time! For imagine, instead of wasting a full hour listening to a Beethoven symphony, on waking up some morning you could simply open your eyes and take it all in, hanging there on your wall, in ten seconds or less, and be refreshed and ready for a fine, fulfilling day?
ACHILLES: Oh, you do poor Beethoven an injustice, Mr. T, a sorry injustice.
TORTOISE: Why, not at all. Beethoven is my second favorite composer. I have spent many long minutes gazing at his beautiful works, both in score and on playing record. The sculpted forms in some of his playing records are so exquisite, you have no idea.
ACHILLES: I must admit, you have floored me. That is an odd way, to put it mildly, to enjoy music. But I suppose you are an odd character, and

this idiosyncrasy makes as much sense, given what I know of you any of the rest.
TORTOISE: A condescending view. How would you like it, if some friend "revealed" to you that you'd never correctly understood a Leonardo painting-in reality, it should be listened to, not looked at, and sixty-two minutes long, in eight movements, and contains long p sages with nothing but the loud ringing of many different-sized bells
ACHILLES: That is an odd way to think of paintings. But .
TORTOISE: Did I ever tell you about my friend the alligator, who enjo music while lying on his back in the sun?
ACHILLES: Not that I recall.
TORTOISE: He has the advantage of having no shell covering his belly So whenever he wants to "hear" a lovely piece, he picks out the appropriate disk and slaps it sharply for an instant against his stomach. The ecstasy of absorbing so many luscious patterns all a once, he tells me, is indescribable. So just think-his experience is, as novel to me as mine is to you!
ACHILLES: But how can he tell the difference between one record an another?
TORTOISE: To him, slapping Bach and Beethoven against his belly are as different as to you slapping a waffle iron and a velvet pad against yo bare back would be!
ACHILLES: In so turning the tables on me, Mr. T, you have shown me on thing your point of view must be just as valid as mine-and if I dI not admit it, I should be an auditory chauvinist pig.
TORTOISE: Well put-admirably put! Now that we have gone over o relative points of view, I will have to confess to being familiar wI your way of listening to playing records, rather than looking at them odd though it does seem to me. The comparison between the tw types of experience was what inspired me to exploit this example as an analogy to what I wish to present to you now, Achilles.
ACHILLES: More of your usual trickery, I see. Well, go on with it-I' all eyes.
TORTOISE: All right. Let's suppose that I came to you one morning with a very big book. You'd say, "Hullo, Mr. Tortoise-what's in that big.. book you're carrying with you?" (if I'm not mistaken); and I'd reply "It's a schematic description of Albert Einstein's brain, down to the cellular level, made by some painstaking and slightly crazy neurolo

gist after Einstein died. You know he bequeathed his brain to science, don't you?" And you'd say, "What in the world are you talking about, `a schematic description of Albert Einstein's brain, down to the cellular level'?" would you not?
ACHILLES: I certainly would! The notion sounds preposterous. I suppose you'd go on roughly as follows: "Probably you're aware, Achilles, that a brain-any brain-is composed of neurons, or nerve cells, linked together by fibers called `axons' to form a highly interconnected network." I'd say interestedly, "Go on." So you would.
TORTOISE: Bravo! You're doing very well! You took the words right out of my mouth! So I would indeed go on, as, you suggested. I'd continue, "The details are beside the point here, but a little knowledge is essential. These neurons are known to fire, which means that a minuscule electric current (regulated by the resistance of the axon) passes down an axon into an adjoining neuron, where it may join other signals in a combined effort to `trigger' this neighbor-neuron to fire in turn. The neighbor, however, will cooperate only if the sum of the incoming currents has reached a threshold value (which is determined by its internal structure); otherwise it will refuse to fire at all." At this point, you might say, "Hmm."
ACHILLES: So how would you go on, Mr. T?
TORTOISE: A good question. I suppose I might say something like this: "The foregoing is a peanut-sized summary of the goings-on in a brain, but I suppose it's sufficient background for an explanation of what this heavy book is that I'm carrying about with me today." If I know you at all, you'd say, "Oh, I'm eager to hear about it, but perhaps I should be warier, lest it contain one of your infamous schemes, whereby you lure poor little unsuspecting me into one of your inescapable absurdities." But I'd reassure you that no such prospect was in store, and thus reassured, you'd urge me to divulge the contents of the book, about which you, having taken a peek in it, might say, "It just looks like a lot of numbers and letters and little abbreviations and things!" And I'd say, "What did you expect? Little pictures of stars and galaxies and atoms, whirling about with formula such as 'E = mc2' scattered hither and thither?"
ACHILLES: At that swipe, I might take offense. I'd say indignantly, "Certainly not."
TORTOISE: Of course you would-rightly so. And then you'd say, "Well, what are all those numbers and things? What do they stand for?"

ACHILLES: Let me go on. I can anticipate, I believe, just how you'd repi
"Each page of this book-and there are around a hundred billion numbered pages in it-corresponds to one neuron and contain numbers recording such aspects relevant to that neuron as: wh' other neurons its axons lead to, what its threshold current is fo firing, and so on. However, I forgot to tell you certain further important facts about the functioning of brains in general-in particular what happens, or is believed to happen (from all we know front neurological research), when thoughts occur in the brain, and especially conscious thoughts." I might object with some vaguely worded complaint about thoughts occurring in the mind, not the brain, but you'd hastily dismiss that remark and say, "We can talk about that some other time-say, for example, if we meet by chance in the Jardin du Luxembourg someday. But for now my goal is to explain the contents of this book to you." I'd be placated, I suppose, as I usually am, so you'd press on with a comment in this vein: "A thought occurs (in the mind or the brain, whichever you prefer -- for now!) when a series of connected neurons fire in succession-mind you, it may not be a long string of individual neurons firing like chain of dominoes falling down one after another-it may be more like several neurons at a time tending to trigger another few, and so forth. More likely than not, some stray neural chains will get started along the side of the mainstream but soon will peter out, as threshold currents are not attained. Thus, one will have, in sum, a broad or narrow squad of firing neurons, transmitting their energy to others in turn, thus forming a dynamic chain that meanders within the brain -its course determined by the various resistances in the axons that are encountered along the way. It would not be out of place to say that `the path of least resistance is followed,' if you follow me." A this point, I'd be sure to comment, "You've surely said a mouthful -let me have a moment to digest it." After mulling over this food for thought you'd so far provided me with, and asking you a few clarifying questions on it, I'd be satisfied that I'd gotten the general picture. Of course you'd probably tell me that if I wanted more information on the subject, I could easily go look it up in almost any popular book about the brain. So then you'd say, "Let me wind up this description of neural activity by briefly describing what accounts for memory, at least as well as has been so far established. Think of the `flashing spot of activity' careening around within the brain ('where all the action is,' so to speak) as a boat traveling across the surface of a pond, such as those toy sailboats that children sometimes bring to the octagonal ponds in the Jardin du Luxembourg, the site

of our hypothetical mind-brain encounter; every boat leaves a disturbance behind it, its wake, as it travels through its medium. The `hot spot' within the brain, just like the boat, leaves its own kind of disturbance, or wake, behind: the neurons that just fired as the signal came through continue to undergo some kind of internal activity perhaps chemical in nature-for a few seconds. A permanent change in the neuron is thereby effected. The change is reflected in some of the numbers we have already spoken of, such as the threshold value for firing, the axon resistances, and so forth. The exact way in which those numbers are modified is, of course, dependent on certain aspects of the internal structure in question-and these aspects themselves are susceptible to numerical encoding." I might well chime in at this point, I imagine, saying "Hence it would be of utmost importance to record those numbers for every neuron, as well as the already-mentioned resistances and thresholds." You would no doubt reply, "An astute remark, Achilles; I had not anticipated you'd see that necessity so quickly. And we might do well to give those numbers a name too: the 'structure-altering numbers' seems adequate to me." To conclude this exchange, I might make the following sort of remark: "The structure-altering numbers are quite remarkable in that they not only describe how other numbers on the page are to change, but also how they themselves are to change, next time the neural flash comes passing through!"
TORTOISE: Oh, you have captured quite well the essence of what might go on between the two of us in an admittedly hypothetical dialogue. I might well say all the words you attributed to me; and I have every reason to believe that you too could come forth with such utterances as you have just proposed. Thus, what have we come to? Ah, yes, I recall-in the hypothetical situation set up, I was in possession of a book, wherein were numerically recorded all the relevant data, neuron by neuron, taken from the brain of Albert Einstein the day of his death. On each page, we have: (1) a threshold value; (2) a set of page numbers, to indicate neurons linked to the present one; (3) the values of resistance of the linking axons; and (4) a set of numbers indicating how the wakelike "reverberations" of the neuron, which occur as a result of its firing, will alter any of the numbers on the page.
ACHILLES: By telling me what you have just said, you would have completed your aim of explaining to me the nature of the heavy tome in your possession. So we would probably have come to the end of our hypothetical dialogue, and I can imagine that we would soon

thereafter bid each other adieu. Yet I cannot help making the observation that the reference you made in that hypothetical dialogue some possible future conversation in these gardens between the pair of us strikingly suggests the circumstances in which we find ourselves today!
TORTOISE: How coincidental! It surely is by pure chance.
ACHILLES: If you don't mind, Mr. T, I'd like to know how this fictitious Einstein book could conceivably shed any light on the "mind-brain problem. Could you oblige me in that respect?
TORTOISE: Willingly, Achilles, Willingly. Would you mind, though, if f added a few extra features to the book, since it is hypothetical' anyway?
ACHILLES: I can't see why I should object at this point. If it's already got a hundred billion pages or so, a few more can't hurt.
TORTOISE: A sporting attitude. The features are as follows. When sound hits the ear, the oscillations set up within the drum are relayed to delicate structures within the middle and inner ear; these eventual' connect to neurons whose duty it is to process such auditory information-thus we could call them "auditory neurons." Likewise, there exist neurons whose duty it is to convey coded directions to any given set of muscles; thus, hand motions are caused by the firing of specific neurons in the brain linked indirectly to the muscles in the hand. The same can be said of the mouth and vocal cords. As our additional information, then, for the book, we'd like to have whatever set of data is required to know precisely how the auditory neuron will be excited by a given incoming tone, if we supply its pitch and loudness. And the other essential chapter in the book is the one that tells in what way the firing of any "mouth-directing neuron" OF "vocal-cord-directing neuron" will affect the muscles of the organ in question.
ACHILLES: I see what you mean. We'd like to know how the internal structure of neurons was affected by any auditory input signal; and also how the firing of certain key neurons, linked to speech organs, would affect those organs.
TORTOISE: Precisely. You know, sometimes, Achilles, it's good to have you around to bounce my ideas off of-they come back at me considerably cleaner than when I came out with them. Your naive simplicity somehow complements my learned verbosity.
ACHILLES: I'd like to bounce that one off on you, Mr. T.

TORTOISE: How's that? What do you mean? Did I say something untoward?
ACHILLES: Now, Mr. T, I assume that in the heavy tome under discussion, there would be numerical conversion tables, which accomplish precisely the tasks just set forth. They would give the neural response of each auditory neuron to any tone; and they would give the changes in mouth shape and vocal-cord tension as a function of the neurons linked to them by nerves in Einstein's body.
TORTOISE: Right you are.
ACHILLES: How could such an extensive documentation of Einstein do anybody any good?
TORTOISE: Why, it could do no good for anyone, except conceivably some starving neurologist.
ACHILLES: So why have you proposed this stupendous volume, this prodigious opus?
TORTOISE: Why, only to tickle my fancy as I mused on mind and brain. But it may serve as a lesson to novices in the field.
ACHILLES: Am I one?
TORTOISE: Doubtless. You'll do very well as a test subject in illustrating the merits of such a book.
ACHILLES: I somehow can't help wondering what old Einstein would think of it all.
TORTOISE: Why, given the book, you could find out.
ACHILLES: I could? I would not know where to begin.
TORTOISE: You would begin by introducing yourself.
ACHILLES: To whom? To the book?
TORTOISE: Yes-it's Einstein, isn't it?
ACHILLES: No, Einstein was a person, not a book.
TORTOISE: Well, that's a matter for some consideration, I'd say. Didn't you say that there is music stored in playing-records?
ACHILLES: I did, and what's more, I described to you how to get at it. Instead of a playing-record being there "all at once," we can use an appropriate needle and other apparatus and extract real, living music from it, which emerges "a bit at a time" just like real music.
TORTOISE: Are you implying that it is only some kind of synthetic imitation?
ACHILLES: Well, the sounds are genuine enough.... They did come plastic, but the music is made of real sounds.
TORTOISE: And yet it's there "all at once" too, isn't it-as a disk?
ACHILLES: As you pointed out to me earlier, yes, it is.
TORTOISE: Now you might at first say that music is sounds, not a record, mightn't you?
ACHILLES: Well, yes, I would; yes.
TORTOISE: Then you are very forgetful! Let me recall to you that to me, music is the record itself, which I can sit and tranquilly admire. 1 don't presume to tell you that to see Leonardo's Madonna of the Rocks as a painting is to miss the point, do I? Do I go around claiming that that painting is only a storage place for long, droning bassoon blasts, melodious piccolo runs, and stately harp dances?
ACHILLES: Why, no, you don't. I guess that either way, we respond to some of the same features of playing-records, even if you like their visual aspect, while I prefer their auditory aspect. At least, I hope that what you like in Beethoven's music corresponds to what I like.
TORTOISE: May or may not. Personally, I don't care. Now, as to whether Einstein was a person, or is in the book.... You should introduce yourself and see.
ACHILLES: But a book can't respond to a statement-it's like a black piece of plastic: It's there "all at once."
TORTOISE: Perhaps that little phrase will serve as a clue to you. Consider what we just said on the subject of music and playing-records.
ACHILLES: You mean, I should try to experience it "a bit at a time"? What bit should I begin at? Should I start at page 1 and read straight on through, to the end?
TORTOISE: Unlikely. Suppose you were going to introduce yourself to Einstein-what would you say?
ACHILLES: Ah . . . "Hullo, Dr. Einstein. My name is Achilles."
TORTOISE: Splendid. Now there are some fine tones of sound for you.
ACHILLES: Tones ... hmmm. Are you planning to use those conversion tables?
TORTOISE: Good gracious, what a brilliant thought. Why didn't it occur to me?
ACHILLES: Well, everybody has inspirations once in a while, you know. Don't feel too bad.
TORTOISE: Well, you came up with a good thought. That's just what we'd try to implement, had we the book.
ACHILLES: So, you mean, we'd look up the possible changes in Einstein's auditory neuron structure resulting from each tone of the utterance?
TORTOISE: Well, roughly. You see, we'd have to do it very carefully. We'd take the first tone, as you suggested, and see which cells it would make fire, and how. That is, we'd see precisely how each number on each page would change. Then we'd go through the book painstakingly page by page, and actually effect those changes. You might call that "round one."
ACHILLES: Would round two be a similar process occasioned by the second tone?
TORTOISE: Not quite. You see, we haven't completed the response to the first tone yet. We've gone through the book once, neuron by neuron. But there is the fact that some of the neurons are firing, you know, so we have to take that into account. Which means we have to proceed to the pages where their axons lead and modify those pages in the way that is directed by the "structure-changing numbers." That is round two. And those neurons, in turn, will lead us to still others, and lo and behold, we're off on a merry loop around the brain.
ACHILLES: Well, when do we ever come to the second tone?
TORTOISE: Good point. It's something I neglected to say earlier. We need to establish a kind of time scale. Perhaps on each page the time taken for the neuron in question to fire is specified-the time it took to fire in real life, in Einstein's brain-a quantity best measured, probably, in thousandths of a second. As the rounds progress, we sum up all the firing times, and when the times add up to the length of the first tone, we start in on the second tone. That way, we can proceed to feed in tone after tone of your self-introductory utterance, modifying the neurons that would respond to that utterance at every step along the way.
ACHILLES: An interesting procedure. But surely a very lengthy one.
TORTOISE: Well, as long as it is all hypothetical, that should not bother us in the least. It would probably take millennia, but let's just say five seconds, for the sake of argument.
ACHILLES: Five seconds required to feed in that utterance? All right. So right now, my picture is that we have altered scores, if not myriads, of pages in that book, changing numbers, on page after page after

page, wherever we were led, either by the previous pages or by t tones that we were feeding in, via the auditory conversion tables'
TORTOISE: Right. And now, once the utterance is finished, neurons continue to fire-from one to the next, the cascade continues-so w perform a strange and elaborate "dance," shuffling back and forth between pages, round after round, without having any auditory input to bother with.
ACHILLES: I can see that something strange is about to happen. Afte another few "seconds" (if we are to stick to that somewhat ridiculous' underestimate) of page turning and number changing, certain of the' "speech neurons" will begin to fire. And we would then do well to consult the tables indicating shape of mouth or tension in vocal cords.
TORTOISE: You have caught wind of what is happening, Achilles. The way to read the book is not from page 1, but according to th directions in the preface, which tell about all the changes that must be effected and give all the rules for how to proceed.
ACHILLES: I suppose that given mouth shape and condition of vocal cords, it would be within grasp to determine what Einstein is "say ing," wouldn't it? Especially given the level of technical advancement we've presupposed, that seems only a minor task. So I suppose he would say something to me.
TORTOISE: I presume so-such as, "Oh, hello. Did you come to visit me Have I died?"
ACHILLES: That is a strange question. Of course he did. TORTOISE: Well, then who's asking you the question?
ACHILLES: Oh, just some silly book. It's not Einstein, of course! You can' trap me into saying that! .
TORTOISE: I wouldn't dream of it. But perhaps you'd like to address some more questions to the book. You could conduct a whole conversation, if you had the patience.
ACHILLES: That is an exciting prospect-I could see just what Einstein would have said in conversations with me, if I'd ever really met him!
TORTOISE: Yes, you could begin by asking how he felt; then proceeding to a description of how glad you were to meet him, since you'd never had the chance during his lifetime-proceeding just as if he were the "real" Einstein, which, of course, you've already decided was out of the question. How do you suppose he would react, when you told him he's not the real Einstein?

ACHILLES: Now, hold on a minute-you're employing the pronoun "he" about a process combined with a huge book. That's no "he"-it's something else. You're prejudicing the question.
TORTOISE: Well, you would address him as Einstein as you fed in questions, wouldn't you? Or would you say, "Hullo, book-of-Einstein's brain-mechanisms, my name is Achilles"? I think you would catch Einstein off guard if you did that. He'd certainly be puzzled.
ACHILLES: There is no "he." I wish you'd quit using that pronoun.
TORTOISE: The reason I'm using it is that I'm simply imagining what you would have said to him, had you actually met him in his hospital bed in Princeton. Certainly you should address questions and comments to the book in the same fashion as you would have to the person Einstein, shouldn't you? After all, the book initially reflects how his brain was on the last day of his life-and he regarded himself as a person then, not a book, didn't he?
ACHILLES: Well, yes. I should direct questions at the book as I would have to the real person had I been there.
TORTOISE: You could explain to him that he had, unfortunately, died, but that his brain had been encoded in a mammoth catalogue after his death, which you are now in possession of, and that you are conducting your conversation by means of that catalogue and its conversion tables for speech.
ACHILLES: He'd probably be most astonished to hear that! TORTOISE: Who? I thought there was no "he"!
ACHILLES: There is no "he" if I'm talking to the book-but if I told it to the real Einstein, he'd be surprised.
TORTOISE: Why would you be telling a live person to his face that he had already died, that his brain had been encoded in a catalogue, and that you were conducting your conversation with him through that catalogue?
ACHILLES: Well, I wouldn't tell it to a live person, I'd tell it to the book, and find out what the live person's reactions would have been. So, in a way, "he" is there. I am beginning to be puzzled ... who am I talking to in that book? Is there somebody alive because it exists? Where are those thoughts coming from?
TORTOISE: From the book. You know that very well.
ACHILLES: Well, then, how can he say how he's feeling? How does a book feel?

TORTOISE: A book doesn't feel any way. A book just is. It's like a chair. It's just there.
ACHILLES: Well, this isn't just a book-it's a book plus a whole process. How does a book plus a process feel?
TORTOISE: How should I know? But you can ask it that question yourself.
ACHILLES: And I know what it'll say: "I'm feeling very weak and my legs ache," or some such thing. And a book, or a book-plus-process, has no legs!
TORTOISE: But its neural structure has incorporated a very, strong memory of legs and leg-aching. Why don't you tell it that it's now no longer a person, but a book-plus-process? Maybe after you've explained that fact in about as much detail as you know it, it would start to understand that and forget about its leg-aching. or what it took for legaching. After all, it has no vested interest in feeling its leg, which it doesn't have, aching. It might as well ignore such things and concentrate on what it does have, such as the ability to communicate with you, Achilles, and to think.
ACHILLES: There is something frightfully sad about this whole process. One of the sadder things is that it would take so much time to get messages in and out of the brain, that before I'd completed many exchanges, I'd be an old man.
TORTOISE: Well, you could be turned into a catalogue too.
ACHILLES: Ugh! And not have any legs left, to run footraces? No thank you!
TORTOISE: You could be turned into a catalogue and continue your thought-provoking conversation with Einstein, as long as someone were managing your book, flipping pages and writing numbers in it. Even better, you could conduct several conversations at once. All we need do is make several copies of the Achilles catalogue, including directions for use, and send it around to whomever you desired. You'd enjoy that.
ACHILLES: Ah, now, that's more exciting. Let's see-Homer, Zeno, Lewis Carroll ... provided that catalogues had been made of their brains, as well. But wait a minute. How am I going to keep track of all those conversations at once?
TORTOISE: No trouble-each one's independent of the others.
ACHILLES: Yes, I know-but I've still got to keep them in my head all at once.

TORTOISE:: Your head? You would have no head, remember.
ACHILLES: No head? Then where would I be? \\hat is going on here?
TORTOISE:: You'd be at all those different places at once, conversations with all those people.
ACHILLES: How would it feel to be conducting conversations with several people at a time?
TORTOISE:: Why don't yon just imagine what it would be like to ask Einstein, presuming, of course, that you had made several copies of ho catalogue, and shipped them about to various of your friends, or anyone, for that matter, and they too were talking with him.
ACHILLES: Well, if 'I didn't tell the Einstein in my possession about it, he'd have no way to know of the other catalogues or conversations. After all, each catalogue has no way of being influenced by any of the other catalogues. So I guess he'd just say that he certainly didn't feel like he was engaging in more than one discussion at a time.
TORTOISE: So that's how you'd feel too, if several of you were engaging III simultaneous conversations.
ACHILLES: I? Which one would be me?
TORTOISE: Any of them: all of them: or perhaps, none of them.
ACHILLES: This is eerie. I don't know where I would be-if anywhere. \nd all of those weird catalogues would be claiming to be me.
TORTOISE: Well, you should expect as much: you do it yourself, don't you? Why, I could even introduce a pair of you-or all of you-to each other.
ACHILLES: Uh-oh. I was waiting for this moment. Every time I see you, you spring something like this on me.
TORTOISE: There just might ensue a teeny scrap over which one was the real one, don't you think so?
ACHILLES:: Oh, this is a diabolical scheme to squeeze the juice out of the human soul. I'm losing a clear sight of who "I" is. Is "I" a person? A process? A structure in my brain? Or is "I" some uncapturable essence that feels what goes on in mm- brain?
ACHILLES:: An interesting question. Let us go hack to Einstein. to examine it. Did Einstein die, or seas he kept on living by the creation of the catalogue?
ACHILLES: Well, to all appearances, some part of his spirit was kept alive by the fact that the data were recorded.

TORTOISE: Even if the book never was used? Would he be alive then?
ACHILLES: Oh, that's a difficult one. I guess I'd have to say "no." Clearly what made him live on was the fact that we "brought him to life from out of the sterile book, "a bit at a time." It was the process, above and beyond the mere data book. He was conversing with us, that's what made him alive. His neurons were firing, in a somewhat figurative way, albeit rather slowly compared to their usual speed-but that’s of no consequence, as long as they were firing.
TORTOISE: Supposing it took you ten seconds to do round one, a hundred seconds to do round two, a thousand seconds to accomplish round three, and so forth. Of course, the book would not know how long all this took, because its only contact with the outside world is through its auditory conversion tables-and in particular, it can never know anything that you don't choose to tell it. Would it still be as alive, despite the enormous sluggishness of its firing after a few rounds?
ACHILLES: I don't see why not. If I too had been catalogued in the same way and my pages were being flipped equally lethargically,. our rates of conversation would be matched. Neither he nor I would have cause to feel any abnormality in the conversation, even if, in the outer world, our mere exchange of greetings lasted millennia.
TORTOISE: You at first spoke of this process that brings out the structure "a bit at a time" as being so important, yet now it seems it doesn't matter if it's constantly slowing down. Eventually the rate of exchange of thoughts would be a syllable a century. And after a while, one neuron would fire every trillion years. Not exactly a sparkling conversation!
ACHILLES: Not in the outer world, no. But to the two of us, who are unaware of the passage of time in the outer world, all is well and normal, as long as someone does our internal bookwork-no matter how slowly. Einstein and I are serenely oblivious to the fast-changing world outside our flipping pages.
TORTOISE: Suppose this faithful neural clerk-let's call him A-kill-ease, just for fun (no relation to present company, of course) just suppose he slipped off one afternoon for a little nip, and forgot to come back....
ACHILLES: Foul play! Double homicide! Or do I mean bibliocide?
TORTOISE: Is it all that bad? Both of you are still there, "all at once."

ACHILLES: "All at once," bah! What's the fun of life if we're not being processed?
TORTOISE: Was it any better at an ever-slowing snail's pace?
ACHILLES: At any pace, it's better. Even a Tortoise's. But say-what's If point of calling the book-tender "A-kill-ease"?
TORTOISE: I just thought I'd let you think about how it would feel if yol brain were not only encoded in a book, but also you were minding th very brain-book (no pun intended, to be sure!).
ACHILLES: I suppose I would have to ask my own book. Or no-wait minute. My book would have to ask me! Oh, I'm so befuddled 1 these confounded and compounded level-confusions you always 1 me with out of the blue! Ah! I have a grand idea. Suppose there w a machine that came along with the books, a machine that does t page turning, the little calculations, and the clerical work. This m we would avoid the problem of human unreliability, as well as your strange twisty loop.
TORTOISE: Suppose so-an ingenious plan. And suppose the machine broke.
ACHILLES: Oh, you have a morbid imagination! What recherché tortures you would put me through!
TORTOISE: Not at all. Unless somebody told you of it, you wouldn't e' be aware of the machine's existence, much less that the machine had broken.
ACHILLES: I don't like this isolation from the outer world. I'd rather h some way of sensing what's going on around me than be depend' upon people telling me things of their own choice. Why not 1 advantage of the neurons which, in life, processed visual input?, like the auditory conversion tables, we could have optical conversion tables. These will be used to create changes in the book accord to the signals from a television camera. Then I could watch the w about me, and react to its events. In particular, I'd soon become aware of the page-turning machine, the book full of so many pages and numbers, and so on....
TORTOISE: Oh, you are determined to suffer. So now you'll perceive fate that is to befall you: You'll "see," by means of input fed into via the television camera and the conversion tables, that the mechanical page-turner that has served you so well has a loose part the just about to slip. That'll scare you, all right. And what good is ~ If you had no optical scanning device, you'd have no way of knowing

what's going on in the world about you, not even with respect to your page-turner. Your thoughts proceed calmly and coolly, unaffected by the cares of the outside world, blithely unaware that they may soon come to a forced end, since the page-turner may break. An idyllic existence! Up until the very end, not a worry!
ACHILLES: But when it breaks, I would be dead and gone. TORTOISE: You would?
ACHILLES: I'd be a lifeless, motionless heap of number-covered sheets. TORTOISE: A pity, I'm sure. But maybe old A-kill-ease would somehow find his way back to his familiar haunts, and take up where the broken machine left off.
ACHILLES: Oh! So I'd be resuscitated. I was dead for a while, and then returned to life!
TORTOISE: If you insist on making these strange distinctions. What makes you any "deader" when the machine breaks than you are when A-kill-ease leaves you unattended for a few minutes or a few years, to play a game of backgammon, to take a trip around the world, or to go get his brain copied into a book?
ACHILLES: I'm obviously deader when the machine breaks, because there is no expectation that I will ever resume functioning. . whereas when A-kill-ease takes off on his sprees, he will eventually return to his duty.
TORTOISE: You mean, if you have been abandoned, you are still alive, just because A-kill-ease has the intention of returning? But when the machine breaks, you are dead?
ACHILLES: That would be a very silly way of defining "aliveness" and "deadness." Certainly such concepts should have nothing to do with the mere intentions of other beings. It would be as silly as saying that a light bulb is "dead" if its owner has no intention of turning it on again. Intrinsically, the light bulb is the same as ever-and that's what counts. In my case, what counts is that that book should be kept intact.
TORTOISE: You mean, that it should all be there, all at once? Its mere presence there is what guarantees your aliveness? Just as the existence of a playing-record is tantamount to the existence of its music?
ACHILLES: A funny image comes into my head. The earth is destroyed, but one record of Bach's music somehow escapes and goes sailing out into the void of space. Does the music still exist? It would be silly

to make the answer depend upon whether it is ever found and played by some humanlike creature-wouldn't it? To you, Mr. T, the music exists as the record itself Similarly, when we come back to that book, I feel that if the book merely sits there, all at once, I'm still there. But if that book is destroyed, I'm gone.
TORTOISE: You maintain that as long as those numbers and conversion tables are in existence, you are essentially, potentially alive?
ACHILLES: Yes; that's it. That's what's all important-the integrity of my brain structure.
TORTOISE: Do you mind if I just ask, "Suppose someone absconded with the instructions in the preface, telling how to use the book?"
ACHILLES: Well, they'd better bring them back, is all I can say. My goose would be cooked if they weren't going to return those instructions. What good's the book without its instructions?
TORTOISE: Once again you are saying that the question as to whether you are alive depends on whether the filcher has good intentions or bad. It could just as well have been the capricious wind, blowing about, which caught hold of those few pages of preface and wafted them into the air. Now there's no question of intention. Would "you" be less alive for that?
ACHILLES: This is a little tricky. Let me go over the question slowly. I die; my brain is transcribed into a book; the book has a set of instructions telling how to process the book's pages in a way that parallels how my neurons fire in my actual brain right now.
TORTOISE: And the book, together with its instructions, lies on a dusty shelf in a far corner of a used book store. A chap comes in and chances upon the oddity. "Egads!" he exclaims, "An Achilles-book! What on earth could that be? I'll buy it and try it!"

ACHILLES: He should be sure to buy the instructions too! It is essential that the book and instructions remain together.
TORTOISE: How close? In the same binding? In the same bag? In the same house? Within a mile of each other? Is your existence somehow diminished if the pages are scattered hither and thither by a breeze? At what precise point would you feel the book had lost its structural integrity? You know, I appreciate a warped playing-record fully as much as a flat one. In fact, it's got an extra bit of charm, to the cultured eye. Why, I have a friend who considers broken records more stylish than the originals! You should see his walls-they're plastered with broken Bach-fragmented fugues, crushed canons,

ruptured ricercari. He delights in it. Structural integrity is in the eye of the beholder, my friend.
ACHILLES: Well, as long as you're asking me to be the beholder, I'd say that if the pages are to be reunited, there is still hope for my survival
TORTOISE: Reunited in whose eyes? Once you're dead, you the beholder remain only in book form (if at all). Once the book's pages start being scattered, will you feel yourself losing structural integrity? Or, front the outside, once I feel that the structure is irretrievably gone, should I conclude that you no longer exist? Or does some "essence' of you exist still, in scattered form? Who will judge?
ACHILLES: Oh, goodness. I have totally lost track of the progress of that poor soul inside the book. And as to what he himself-or I myself -would be feeling, I am even more unsure.
TORTOISE: "That poor soul inside the book"? Oh, Achilles! Are you still clinging to that old notion that it's "you" somehow there, inside that book? If I am correct in my memory, you were so reluctant at first to accept that kind of idea when I suggested that you really were talking to Einstein himself.
ACHILLES: Well, I was reluctant until I saw that it-the book-seemed to feel, or at least to express, all his-Einstein's-emotions, or what seemed like emotions. But maybe you're right to chide me-maybe I should just trust the old, familiar commonsense view that the only' real "I" is right here, inside my very own living, organic brain.
TORTOISE: You mean, the old, familiar "ghost-inside-the-machine" theory, is that it? What is it, inside there, that this "you" is?
ACHILLES: It's whatever feels all these emotions that I express.
TORTOISE: Maybe the feeling of those emotions is the sheer physical event of having a shower of electrochemical activity come flying through some one of the various neural pathways inside your brain. Maybe you use the word "feeling" to describe such an event.
ACHILLES: That sounds wrong, because the book uses the word "feeling," if I do, and yet it can feel no electrochemical activity surging. All that the book "feels" is its numbers changing. Perhaps "feeling" is synonymous with the existence of any kind of neural activity, simulated or otherwise.
TORTOISE: Such a view would place undue stress on the unfolding of feeling "a bit at a time." While the time development of a neural structure undoubtedly seems to us like the essence of feeling

why could it not be that feelings, like playing-records and paintings, a there "all at once"?
ACHILLES: The difference I can immediately spot between a playing record of a piece of music, and a mind, is that the former does n change by evolving "a bit at a time"; but a mind, in its interaction over a span of time with the exterior world, gets modified a way that was not originally inherent in its physical structure.
structure.
TORTOISE: You have a good point. A mind, or brain, interacts with t world and thus is subject to change that one cannot predict by knowing the structure of the brain alone. But this does not in any w diminish the "aliveness" of said mind, when it introspectively ponders some thought, without any interference from without. During such a period of introspection, the changes it undergoes are inhere in it. Though it is evolving "a bit at a time," it is inherently there " at once." I can clarify what I mean by drawing a parallel to a simpler. system. The entire path of a thrown grapefruit is inherent once t grapefruit is released. Watching the fruit in flight is one way-t usual way-of experiencing its motion; it could be labeled the "t at-a-time" picture of its motion. But just knowing its initial position and velocity is another equally valid way of experiencing the motion this picture of the motion could be labeled the "all-at-once" picture Of course, in this picture we assume no interference by passing storks and so forth. A brain (or a brain catalogue) shares this dual nature; as long as it is not interacting with the exterior world a being modified in ways foreign to it, its time development can viewed either in the "bit-at-a-time" picture or in the "all-at-on( picture. The latter picture is one that I advocate and that I thought you had come to agree with, when you described the record sailing out into space.
ACHILLES: I see things so much more easily in the "bit-at-a-time" picture.
TORTOISE: Of course you do. The human brain is set up to see that that way. Even in a simple case, like the motion of a flying grapefruit the brain is more satisfied to see the actual motion "a bit at a tin than it is to visualize a parabola "all at once." But simply coming recognize that there is an "all-at-once" picture was a great step the human mind, because it amounted to the recognition that so regularities exist in nature, regularities that guide events in predictable channels.

ACHILLES: I recognize that feeling exists in the "bit-at-a-time" picture. I know this because that is how I feel my own feelings. But does it also exist in the "all-at-once" picture? Are there "feelings" in a motionless book?
TORTOISE: Is there music in a motionless playing-record?
ACHILLES: I am not sure any longer how to answer that question. But I still want to learn if "I" am in the Achilles book, or if the "real Einstein" is in the Einstein book.
TORTOISE: So you may; but for my part, I still want to learn if "you" are anywhere at all. So let us stick to the comfortable "bit-at-a-time" picture, and imagine the internal processes of your brain, Achilles. Imagine the "hot-spot," that infamous shower of electrochemical activity, as it zigzags its way along the "path of least resistance." You, Achilles, or what you refer to as "I," have no control over which path is the one of least resistance.
ACHILLES: I don't? Is it my subconscious, then? I know I sometimes feel my thoughts "spring up" to me as if motivated by subconscious tendencies.
TORTOISE: Perhaps "subconscious" is a good name for neural structure. It is, after all, your neural structure that, at any moment, determines which path is the one of least resistance. And it is because of that neural structure that the "hot-spot" follows that curlicue path and none other. This swirling electrochemical activity constitutes the mental and emotional life of Achilles.
ACHILLES: A weird and mechanistic song, Mr. T. I bet you could make it sound even stranger. Wax lyric if you can; let the verbs have their fling! Of Brain, Mind, and Man, let's hear the Tortoise sing!
TORTOISE: Your verse is surely inspired by the gods, my dear companion. The brain of Achilles is like a labyrinth of rooms; each room has many doors leading to other rooms-and many of the rooms are labeled. (Each "room" may be thought of as a complex of a few or a few dozen neurons-perhaps more; and "labeled" rooms are special complexes composed mostly of speech-neurons.) As the "hot spot" tears through this labyrinth, flinging open and slamming shut doors, from time to time it enters a "labeled" room. At that point your throat and mouth contract: you say a word. All the while the neural flash loops relentlessly along its Achillean path, in shapes stranger than the dash of a gnat-hungry swallow; every twist, every turn is foreordained by the neural structure present in your brain,

until sensory input messages interfere; then the flash veers away from the path it would have followed. And so it goes-room after room after labeled room is visited. You are speaking.
ACHILLES: I don't always speak. Sometimes I merely sit and think.
TORTOISE: Granted. The labeled rooms may have their lights turned low -a sign for non-utterance: you don't speak the words aloud. A "thought" occurs, silently. The hot spot continues-depositing, at door after door, either a drop of oil on the hinge to loosen it, or a drop of water to corrode it. Some doors have such rusty hinges they can't be opened. Others are so often oiled they nearly open by themselves. Thus traces of the present are deposited for the future: the "I" of now leaves messages and memories for the "I" of a time to come. This neural dance is the dance of the soul; and the sole choreographer of the soul is physical law.
ACHILLES: Normally, I think that I'm in control of what I think; but the way you put it turns it all around backward, so that it sounds like "I" am just what comes out of all this neural structure and natural law. It makes what I consider myself sound at best like a by-product of an organism governed by natural law and, at worst, like an artificial concept produced by my distorted perspective. In other words, you make me feel as if I don't know who-or what-I am, if anything.
TORTOISE: This is a very important matter to bring up. How can you "know" what you are? First of all, what does it mean to know something, anything, at all?
ACHILLES: Well, I presume that when I know something-or when, should I say, my brain knows something-there is a path that snakes through my brain, running through rooms, many of which are labeled. If I ever think a thought about the subject, my neural flash swishes along that path quite automatically, and if I am conversing, each time it passes through a labeled room, a sound of some type comes out. But of course I don't need to think about my neural flash for it to do this very competently. It seems as if I function quite well without me!
TORTOISE: Well, it's true that the "path of least resistance" does take care of itself quite well. But we can equate the result of all this functioning with you, Achilles. You needn't feel that your self is dispensed with in this analysis.
ACHILLES: But the trouble with this picture is that my "self" is not in control of myself.

TORTOISE: I suppose it depends upon what you mean by "control," Achilles. Clearly you cannot force your neural flash to deviate from the path of least resistance; but the Achilles of one moment is directly affecting what will become the path of least resistance in the next moment. That should give you some feeling that "you," whatever you are, have some control over what you will feel and think and do, in the future.
ACHILLES: Well, yes, that is an interesting way to look at it, but it still means that I can't just think whatever I want to think, but only what was set up for me to think, by an earlier version of me.
TORTOISE: But what is set up in your brain is what you want to think about, to a large degree. But sometimes, admittedly, you can't make your brain function as you will it to. You forget someone's name; you can't concentrate on something important; you become nervous despite your best attempts to control yourself; all of this reflects what you said: that in a sense your "self" is not in control of yourself. Now it is up to you whether or not you wish to identify the Achilles of now with the Achilles of bygone times. If you do choose to identify with your former selves, then you can say that "you"-meaning the you that used to exist-are in control of what you are today; but if you prefer to think of yourself as existing solely in the present, then indeed it is true that what "you" do is under control of natural law and not under control of an independent "soul."
ACHILLES: I am beginning to feel through this discussion that I "know" myself a little better. I wonder if it would be possible for me to learn all about my neural structure-so much so that I would be able to predict the path of my neural flash before it even covered its path! Surely, this would be total, exquisite self-knowledge.
TORTOISE: Oh, Achilles, you have innocently thrown yourself into the wildest of paradox, without the benefit of even the slightest coaching on my part! Maybe one day you will learn to do this regularly; then you will be able to dispense with me entirely!
ACHILLES: Enough of your mockery! Let's hear about this paradox I've inadvertently fallen into.
TORTOISE: How could you learn all about yourself? You might try reading the Achilles book.
ACHILLES: That would certainly be a phenomenal project. A hundred billion pages! I'm afraid I'd fall asleep listening to myself read. Or -horrors-I might even die before I had completed the task! But

suppose I were a very fast reader and managed to learn the contents of the whole book within the time allotted to me on the surface of our green sphere.
TORTOISE: So now you'd know all about Achilles-before he read the Achilles book! But you are quite ignorant about the Achilles who exists now!
ACHILLES: Oh, what a quandary! The fact that I read the book makes the book obsolete. The very attempt to learn about myself changes me from what I was. If only I could have a bigger brain, capable of digesting all of the complexity of myself. Yet I can see that even that would be of no avail, for possession of a bigger brain would make me all the more complex yet! My mind simply can't understand all of itself. All I can know is the outline, the basic idea. Beyond a certain point, I cannot go. Although my brain structure is right there in my head, exactly where "I" am, still its nature is not accessible to this "I." The very entity that constitutes "I"-and I am of necessity ignorant of it. My brain and "I" are not the same!
TORTOISE: A droll dilemma-the stuff of life's many hilarities. And now, perhaps, Achilles, we can pause to ponder one of the original questions that prompted this discussion: "Do thoughts occur in the mind, or in the brain?"
ACHILLES: By now, I hardly know what is meant by "mind"-except, of course, as a sort of poetic expression for the brain, or its activities. The term reminds me of "beauty." It is not something that one can locate in space-yet it is not hovering in an ethereal otherworld, either. It is more like a structural feature of a complex entity.
TORTOISE: Where lies the beauty, if I may rhetorically ask, of an etude by Scriabin? In the sounds? Among the printed notes? In the ear, mind, or brain of the beholder?
ACHILLES: It seems to me that "beauty" is just a sound that we utter whenever our neural flash passes through a certain region of our brains-a certain "labeled room." It is tempting to think that to this sound there corresponds an "entity," some kind of "existing thing." In other words, because it is a noun, we think of beauty as a "Thing"; but maybe "beauty" denotes no Thing at all; the word is just a useful sound which certain events and perceptions make us want to pronounce.
TORTOISE: I would go further, Achilles: I would surmise that this is a property of many words-especially words like "beauty," "truth,"

"mind," and "self." Each word is but a sound which we are caused to utter, at various times, by our swooping, careening neural flash. And to each sound, we can hardly help but believe that there corresponds an Entity-a "Real Thing." Well, I will say that the benefit that one derives from using a sound imbues it with a proportionate amount of what we call "meaning. " But as to whether that sound denotes any Thing ... how would we ever know that?
ACHILLES: How solipsistically you view the universe, Mr. T. I thought such views were highly unfashionable in this day and age! One is supposed to consider that Things have an Existence of their own.
TORTOISE: Ah, me, yes, perhaps they do-I never denied it. I suppose it's a pragmatic view of the meaning of "meaning," useful in the bustle of everyday life, to make the assumption that some sounds do stand for Existing Entities. And the pragmatic value of this assumption may be its best justification. But let's get back to the elusive site of the "real you," Achilles!
ACHILLES: Well, I'm at a loss to say if it's anywhere at all, even though another part of me is practically jumping to shout, "The `real me' is here now." Maybe the whole point is that whatever mechanism makes me make everyday statements like "Spades are trump" is quite like the mechanism which makes me-or the Achilles book-say sentences such as "The `real me' is here now." For certainly if I, Achilles, could say it, so could the book version of me-in fact, it would undoubtedly do so. Though my own first reflex is to affirm, "I know I exist; I feel it," maybe all these "feelings" are just an illusion; maybe the "real I" is all an illusion; maybe, just like "beauty," the sound "I" denotes no Thing at all, but is just a useful sound that we on occasion feel compelled to pronounce because our neural structures are set up that way. Probably that is what is happening when I say "I know I'm alive" or similar things. This would also explain why I got so puzzled when you brought up the version in which several copies of the Achilles book would be distributed to various people, and "I" would have conversations with all of them at once. I demanded to know where the "real I" was, and how "I" could take care of several conversations at once; I see now that each copy of the book has that structure built into it, that makes it automatically make pronouncements such as "I am the real me; I am feeling my own emotions and anybody else who claims to be Achilles is a fraud." But I can see that the mere fact that it utters such things doesn't mean that it has "real feelings"; and perhaps even more to the point, the mere fact that I, Achilles, utter such things, doesn't

really mean I am feeling anything (whatever that would mean!). In the light of all this, I am beginning to doubt if such phrases have any meaning at all.
TORTOISE: Well, of course, utterances about "feeling" one way or an other are very useful, in practical terms.
ACHILLES: Oh, without doubt-I shan't shun them just because this conversation has taken place; nor shall I shun the term "I," as you can see for yourself. But I won't imbue it with such "soulful" meaning as I have heretofore tended to do, rather instinctively, and, I have to say, dogmatically.
TORTOISE: I am glad that for once we seem to be in agreement in our conclusions. I see that the hour is growing late; dusk is approaching -just the time when all my forces seem to gather, and I feel quite energetic. I know you must have been disappointed by the "no-show" of your friend; how's about a little footrace back to the fifth century B.C.?
ACHILLES: What a capital idea! But just to be fair, I'll give you a head start of, oh, three centuries, since I'm so fleet of foot.
TORTOISE: You're a mite cocky, Achilles.... You may not find it so easy to catch up with an Energetic Tortoise.
ACHILLES: Only a fool would bet on a slow-footed Tortoise, racing against me. Last one to Zeno's house is a monkey's uncle!

Douglas R. Hofstadter

Reflections

"Well, all these fantasies have been fun, but they can't really tell us anything. They're just so much science fiction. If you want to learn the truth-the hard facts-about something, you have to turn to real science, which so far has had little to tell us about the ultimate nature of the mind." This response conjures up a familiar but impoverished vision of science as a collection of precise mathematical formulae, meticulous experiments, and vast catalogues of species and genera, ingredients and recipes. This is the picture of science as strictly a data-gathering enterprise in which imagination is tightly reined in by incessant demands for proof. Even some scientists have this vision of their profession, and are

deeply suspicious of their more playful colleagues, however eminent Perhaps some symphony orchestra players view their business as nothing but precise noise-making produced under conditions of militaristic discipline. If so, think what they are missing.
In fact, of course, science is an unparalleled playground of the imagination, populated by unlikely characters with wonderful names (messenger RNA, black holes, quarks) and capable of performing the most amazing deeds: sub-atomic whirling dervishes that can be in several places everywhere and nowhere-at the same time; molecular hoop-snakes biting their own tails; self-copying spiral staircases bearing coded instructions; miniature keys searching for the locks in which they fit, on floating odysseys in a trillion synaptic gulfs. So why not brain-book immortality dream-writing machines, symbols that understand themselves, and fraternal homunculi without arms, legs, or heads, sometimes blindly following orders like the sorcerer's broom, sometimes feuding and conniving, sometimes cooperating? After all, some of the most fantastic ideas presented in this book-Wheeler's solitary electron weaving the universe, for example, or Everett's many-worlds interpretation of quantum mechanics, or Dawkins' suggestion that we are survival machines for our genes-have been proposed in complete seriousness by eminent scientists. Should we take such extravagant ideas seriously? We should certainly try, for how else will we ever learn whether these are the conceptual giant steps we need to escape from the most obscure riddles of the self and consciousness? Coming to understand the mind will probably require new ways of thinking that are at least as outrageous-at first-as Copernicus's shocking suggestion that the Earth goes around the Sun, or Einstein's bizarre claim that space itself could be curved. Science advances haltingly, bumping against the boundaries of the unthinkable: the things declared impossible because they are currently unimaginable. It, is at the speculative frontier of thought experiment and fantasy that these boundaries get adjusted.
Thought experiments can be systematic, and often their implications can be rigorously deduced. Consider Galileo's crystal-clear reductio ad absurdum of the hypothesis that heavier objects fall faster than lighter objects. He asks us to imagine taking a heavy object, A, and a light object, B, and tying them together with a string or chain before dropping them off a tower. By hypothesis, B falls slower, and hence should act as a drag on A; thus A tied to B should fall slower than A by itself. But A tied to B is itself a new object, C, which is heavier than A, and hence, by hypothesis, C should fall faster than A by itself. A tied to B cannot at the same time fall faster and slower than A by itself (a contradiction or absurdity), so the hypothesis must be false.

On other occasions thought experiments, however systematically developed, are intended merely to illustrate and enliven difficult ideas. And sometimes the boundaries between proof, persuasion, and pedagogy cannot be drawn. In this book there are a variety of thought experiments designed to explore the implications of the hypothesis that materialism is true: the mind or self is not another (non-physical) thing, in miraculous interaction with the brain, but somehow a natural and explainable product of the brain's organization and operation. "The Story of a Brain" presents a thought experiment that is meant, like Galileo's, to be a reductio ad absurdum of its main premise-in this case, materialism in the guise of "the neural theory of experience." "Prelude, Ant Fugue," "Where Am I?" and "A Conversation with Einstein's Brain," on the other hand, are designed to support materialism by helping thinkers over obstacles that have traditionally stood in the way of comprehending it. In particular, these thought experiments are designed to provide a plausible substitute for the otherwise compelling idea of the self as a sort of mysterious, indivisible pearl of mind-stuff. "Minds, Brains, and Programs" is intended to refute one version of materialism (roughly, the version we defend), while leaving some underdescribed and unexplored materialistic alternatives untouched.
In each of these thought experiments there is a narrative problem of scale: how to get the reader's imagination to glide over a few billion details and see the woods and not just the trees. "The Story of a Brain" is silent about the staggering complexity of the devices to which the imagined brain parts would have to be attached. In "Where Am I?" the virtual impossibility of using radio links to preserve the connectivity in hundreds of thousands of nerves is conveniently ignored, and the even less likely feat of making a computer duplicate of a human brain that, could operate synchronously is presented as nothing more than a fancy bit of technology. "Minds, Brains, and Programs" invites us to imagine a person hand simulating a language-processing program which, if it were realistic, would be so huge that no person could perform the steps for a single interchange in less 'than a lifetime, but we are cajoled into imagining the system engaging in Chinese conversations occurring in a normal time scale. The problem of scale is faced directly in "A Conversation with Einstein's Brain," where we are asked to tolerate a book with a hundred billion pages we can flip through fast enough to extract a few conversational gems from the posthumous Prof. Einstein.
Each setting of the dials on our intuition pump yields a slightly different narrative, with different problems receding into the background
and different morals drawn. Which version or versions should be trusted is a matter to settle by examining them carefully, to see which features

of the narrative are doing the work. If the oversimplifications are the source of the intuitions, rather than just devices for suppressing irrelevant complications, we should mistrust the conclusions we are invited to draw. These are matters of delicate judgment, so it is no wonder that a generalized and quite justified suspicion surrounds such exercises of imagination and speculation.
In the end we must turn to the rigorous methods of hard science the experiments, deductions, and mathematical analyses-to keep the speculations honest. These methods provide raw materials for suggesting and testing hypotheses, and even serve often as powerful engines of discovery in their own right. Still, the storytelling side of science is not just peripheral, and not just pedagogy, but the very point of it all. Science properly done is one of the humanities, as a fine physics teacher once said. The point of science is to help us understand what we are and how we got here, and for this we need the great stories: the tale of how, once upon a time, there was a Big Bang; the Darwinian epic of the evolution of life on Earth; and now the story we are just beginning to learn how to tell: the amazing adventure of the primate autobiographers who finally taught themselves how to tell the story of the amazing adventure of the primate autobiographers.

D.C.D.

Chapter 25: An Epistemological Nightmare

2007-02-14T06:00:00.000-08:00

Scene 1. Frank is in the office of an eye doctor. The doctor holds up a book and asks "What color is it?" Frank answers, "Red." The doctor says, "Aha, just as I thought! Your whole color mechanism has gone out of kilter. But fortunately your condition is curable, and I will have you in perfect shape in a couple of weeks."

Scene 2. (A few weeks later.) Frank is in a laboratory in the home of an experimental epistemologist. (You will soon find out what that means!) The epistemologist holds up a book and also asks, "What color is this book?" Now, Frank has been earlier dismissed by the eye doctor as "cured." However, he is now of a very analytical and cautious temperament, and will not make any statement that can possibly be refuted. So Frank answers, "It seems red to me."

EPISTEMOLOGIST: Wrong!

FRANK: I don't think you heard what I said. I merely said that it seems red to me.

EPISTEMOLOGIST: I heard you, and you were wrong.

From Philosophical Fantasies by Raymond M. Smullyan, to be published by St. Martins Press, N.Y., in 1982.

FRANK: Let me get this clear; did you mean that I was wrong that this book is red, or that I was wrong that it seems red to me?
EPISTEMOLOGIST: I obviously couldn't have meant that you were wrong in that it is red, since you did not say that it is red. All you said was that it seems red to you, and it is this statement which is wrong.
FRANK: But you can't say that the statement "It seems red to me" is wrong.
EPISTEMOLOGIST: If I can't say it, how come I did?
FRANK: I mean you can't mean it.
EPISTEMOLOGIST: Why not?
FRANK: But surely I know what color the book seems to me!
EPISTEMOLOGIST: Again you are wrong.
FRANK: But nobody knows better than I how things seem to me.
EPISTEMOLOGIST: I am sorry, but again you are wrong.
FRANK: But who knows better than I?
EPISTEMOLOGIST: I do.
FRANK: But how could you have access to my private mental states?
EPISTEMOLOGIST: Private mental states! Metaphysical hogwash! Look, I am a practical epistemologist. Metaphysical problems about "mind versus "matter" arise only from epistemological confusions. Epistemology is the true foundation of philosophy. But the trouble with all past epistemologists is that they have been using wholly theoretical methods, and much of their discussion degenerates into mere word games. While other epistemologists have been solemnly arguing such questions as whether a man can be wrong when he asserts that he believes such and such, I have discovered how to settle such questions experimentally.
FRANK: How could you possibly decide such things empirically?
EPISTEMOLOGIST: By reading a person's thoughts directly.
FRANK: You mean you are telepathic?
EPISTEMOLOGIST: Of course not. I simply did the one obvious thing which should be done, viz. I have constructed a brain-reading machine-known technically as a cerebrescope-that is operative right now in this room and is scanning every nerve cell in your brain. I thus can read your every sensation and thought, and it is a simple objective truth that this book does not seem red to you.
FRANK (thoroughly subdued): Goodness gracious, I really could have sworn that the book seemed red to me; it sure seems that it seems red to me!
EPIS T EMOLOGIST: I'm sorry, but you are wrong again.
FRANK: Really? It doesn't even seem that it seems red to me? It sure seems like it seems like it seems red to me!
EPISTEMOLOGIST: Wrong again! And no matter how many times you reiterate the phrase "it seems like" and follow it by "the book is red" you will be wrong.
FRANK: This is fantastic! Suppose instead of the phrase "it seems like" I would say "I believe that." So let us start again at ground level. I retract the statement "It seems red to me" and instead I assert "I believe that this book is red." Is this statement true or false?
EPISTEMOLOGIST: Just a moment while I scan the dials of the brainreading machine-no, the statement is false.
FRANK: And what about "I believe that I believe that the book is red"?
EPISTEMOLOGIST (consulting his dials): Also false. And again, no matter how many times you iterate "I believe," all these belief sentences are false.
FRANK: Well, this has been a most enlightening experience. However, you must admit that it is a little hard on me to realize that I am entertaining infinitely many erroneous beliefs!
EPISTEMOLOGIST: Why do you say that your beliefs are erroneous? FRANK: But you have been telling me this all the while!
EPISTEMOLOGIST: I most certainly have not!
FRANK: Good God, I was prepared to admit all my errors, and now you tell me that my beliefs are not errors; what are you trying to do, drive me crazy?
EPISTEMOLOGIST: Hey, take it easy! Please try to recall: When did I say or imply that any of your beliefs are erroneous?
FRANK: Just simply recall the infinite sequence of sentences: (1) I believe this book is red; (2) I believe that I believe this book is red; and so forth. You told me that every one of those statements is false.
EPISTEMOLOGIST: True.
FRANK: Then how can you consistently maintain that my beliefs in all these false statements are not erroneous?

EPISTEMOLOGIST: Because, as I told you, you don't believe any of them. FRANK: I think I see, yet I am not absolutely sure.
EPISTEMOIOGIST: Look, let me put it another way. Don't you see that the very falsity of each of the statements that you assert saves you from an erroneous belief in the preceding one? The first statement is, as I told you, false. Very well! Now the second statement is simply to the effect that you believe the first statement. If the second statement were true, then you would believe the first statement, and hence your belief about the first statement would indeed be in error. But fortunately the second statement is false, hence you don't really believe the first statement, so your belief in the first statement is not in error. Thus the falsity of the second statement implies you do not have an erroneous belief about the first; the falsity of the third likewise saves you from an erroneous belief about the second, etc.
FRANK: Now I see perfectly! So none of my beliefs were erroneous, only the statements were erroneous.
EPISTEMOLOGIST: Exactly.
FRANK: Most remarkable! Incidentally, what color is the hook really?
EPISTEMOLOGIST: It is red.
FRANK: What!
EPISTEMOLOGIST: Exactly! Of course the hook is red. What's the matter with you, don't you have eyes?
FRANK: But didn't I in effect keep saying that the book is red all along?
EPISTEMOLOGIST: Of course not! You kept saying it seems red to you, it seems like it seems red to you, you believe it is red, you believe that you believe it is red, and so forth. Not once did you say that it is red. When I originally asked you "What color is the book?" if you had simply answered "red," this whole painful discussion would have been avoided.
Scene 3. Frank comes back several months later to the home of the epistemologist.
EPISTEMOLOGIST: How delightful to see you! Please sit down.
FRANK (seated): I have been thinking of our last discussion, and there is much I wish to clear up. To begin with, I discovered an inconsistency in some of the things you said.
EPISTEMOLOGIST: Delightful! I love inconsistencies. Pray tell!

FRANK: Well, you claimed that although my belief sentences were false, I did not have any actual beliefs that are false. If you had not admitted that the book actually is red, you would have been consistent. But your very admission that the book is red, leads to an inconsistency.
EPISTEMOLOGIST: How so?
FRANK: Look, as you correctly pointed out, in each of my belief sentences "I believe it is red," "I believe that I believe it is red," the falsity of' each one other than the first saves the from an erroneous belief in the preceeding one. However, you neglected to take into consideration the first sentence itself. The falsity of the first sentence "I believe it is red," in conjunction with the fact that it is red, does imply that I do have a false belief.
EPISTEMOLOGIST: I don't see why.
FRANK: It is obvious! Since the sentence "I believe it is red" is false, then I in fact believe it is not red, and since it really is red, then I do have a false belief. So there!
EPISTEMOLOGIST (disappointed): I am sorry, but your proof obviously fails. Of course the falsity of the fact that you believe it is red implies that you don 't believe it is red. But this does not mean that you believe it is not red!!
FRANK: But obviously I know that it either is red or it isn't, so it 'l don't believe it is, then I must believe that it isn't.
EPISTEMOLOGIST: Not at all. I believe that either Jupiter has life or it doesn't. But I neither believe that it does, nor do I believe that it doesn't. I have no evidence one way or the other.
FRANK: Oh well, I guess you are right. But let us come to more important matters. I honestly find it impossible that I can be in error concerning my own beliefs.
EPISTEMOLOGIST Must we go through this again? I have already patiently explained to you that you (in the sense of your beliefs, not your statements) are not in error.
FRANK: Oh, all right then, I simply do not believe that even the statements are in error. Yes, according to the machine they are in error, but why should I trust the machine?
EPISTEMOLOGIST: Whoever said you should trust the machine? FRANK: Well, should I trust the machine?
EPISTEMOLOGIST: That question involving the word "should" is out of my domain. However, if you like, I can refer you to a colleague who

is an excellent moralist-he may be able to answer this for you.
FRANK: Oh come on now, I obviously didn't mean "should" in a moralistic sense. I simply meant "Do I have any evidence that this machine is reliable?"
EPISTEMOLOGISI: Well, do you?
FRANK: Don't ask me! What I mean is should you trust the machine?
EPISTEMOEOGt5T: Should I trust it? I have no idea, and I couldn't care less what I should do.
FRANK: Oh, your moralistic hangup again. I mean, do you have evidence that the machine is reliable?
EPISTEMOLOGIST: Well of course!
FRANK: Then let's get down to brass tacks. "hat is your evidence?
EPISTEMOEOCIST: You hardly can expect that I can answer this for you in an hour, a day, or a week. If you wish to study this machine with me, we can do so, but I assure you this is a matter of several years. At the end of that time, however, you would certainly not have the slightest doubts about the reliability of the machine.
FRANK: Well, possibly I could believe that it is reliable in the sense that its measurements are accurate, but then I would doubt that what it actually measures is very significant. It seems that all it measures is one's physiological states and activities.
EPISTEMOLOGIST: But of course, what else would you expect it to measure?
FRANK: I doubt that it measures my psychological states, my actual beliefs.
EPISTEMOLOGIST: Are we back to that again? The machine does measure those physiological states and processes that you call psychological states, beliefs, sensations, and so forth.
FRANK: At this point I am becoming convinced that our entire difference is purely semantical, All right, I will gram that your machine does correctly measure beliefs in Your sense of the word "belief," but I don't believe that it has any possibility of measuring beliefs in my sense of the word "believe." In other words I claim that our entire deadlock is simply due to the fact that you and I mean different things by the word "belief."
EPISTEMOLOCIST: Fortunately, the correctness of your claim can he decided experimentally. It so happens that I now have two brain-read
jug machines in my office, so I now direct one to tour brain to find out what you mean by "believe" and now I direct the other to my own brain to find out what I mean by "believe," and now I shall compare the two readings. Nope, I'm sorry, but it turns out that we mean exactly the same thing by the word ''believe.
FRANK Oh, hang your machine! Do you believe we mean the same thing by the word "believe"?
EPISTEMOLOCIST:: Do I believe it? just a moment while I check with the machine. Yes, it turns out I do believe it.
FRANK: My goodness, do you mean to say that you can't even tell me what you believe without consulting the machine?
EPISTEMOLOCIST: Of' course not.
But most people when asked what they believe simply tell you. Why do you, in order to find out your beliefs, go through the fantastically roundabout process of directing a thought-reading machine to your own brain and then finding out what you believe on the basis of the machine readings?
EPISTEMOLOCIST:: What other scientific, objective way is there of finding out what I believe?
FRANK: Oh, come now, why don't you just ask yourself?
EPISTEMOLOCIST: (sadly): It doesn't work. Whenever I ask myself what I believe, I never get any answer!
FRANK: Well, why don't you just stale what you believe?
EPISTEMOLOCIST:: How can I state what I believe before I know what I believe?
FRANK: Oh, to hell with your knowledge of what you believe; surely you have some idea or belief as to what you believe, don't you?
EPISTEMOLOCIST: Of course I have such a belief. But how do I find out what this belief is?
FRANK: I am afraid we are getting into another infinite regress. Look, at this point I am honestly beginning to wonder whether you may be going crazy.
EPISTEMOLOCIST:: Let me consult the machine. Yes, it turns out that I may be going crazy.
I RANK: Good God, man, doesn't this frighten you?
EPISTEMOLOCIST:: Let me check! Yes, it turns out that it does frighten me.

FRANK: Oh please, can't you forget this damned machine and just tell me whether you are frightened or not?
EPISTEMOLOGIST: I just told you that I am. However, I only learned of this from the machine.
FRANK: I can see that it is utterly hopeless to wean you away from the machine. Very well, then, let us play along with the machine some more. Why don't you ask the machine whether your sanity can be saved?
EPISTEMOLOGIST: Good idea! Yes, it turns out that it can be saved.
FRANK: And how can it be saved?
EPISTEMOLOGIST: I don't know, I haven't asked the machine.
FRANK: Well, for God's sake, ask it!
EPISTEMOLOGIST: Good idea. It turns out that ... FRANK: It turns out what?
EPISTEMOLOGIST: It turns out that ...
FRANK: Come on now, it turns out what?
EPISTEMOLOGIST: This is the most fantastic thing I have ever come across! According to the machine the best thing I can do is to cease to trust the machine!
FRANK: Good! What will you do about it?
EPISTEMOLOGIST: How do I know what I will do about it, I can't read the future?
FRANK: I mean, what do you presently intend- to do about it?
EPISTEMOLOGIST: Good question, let me consult the machine. According to the machine, my current intentions are in complete conflict. And I can see why! I am caught in a terrible paradox! If the machine is trustworthy, then I had better accept its suggestion to distrust it. But if I distrust it, then I also distrust its suggestion to distrust it, so I am really in a total quandary.
FRANK: Look, I know of someone who I think might be really of help in this problem. I'll leave you for a while to consult him. Au revoir!
Scene 4. (Later in the day at a psychiatrist's office.)
FRANK: Doctor, I am terribly worried about a friend of mine. He calls himself an "experimental epistemologist."

DOCTOR: Oh, the experimental epistemologist. There is only one in the world. I know him well!
FRANK: That is a relief. But do you realize that he has constructed a mind-reading device that he now directs to his own brain, and whenever one asks him what he thinks, believes, feels, is afraid of, and so on, he has to consult the machine first before answering? Don't you
think this is pretty serious?
DOCTOR: Not as serious as it might seem. My prognosis for him is actually quite good.
FRANK: Well, if you are a friend of his, couldn't you sort of keep an eye on him?
DOCTOR: I do see him quite frequently, and I do observe him much. However, I don't think he can be helped by so-called "psychiatric treatment." His problem is an unusual one, the sort that has to work itself out. And I believe it will.
FRANK: Well, I hope your optimism is justified. At any rate I sure think I need some help at this point!
DOCTOR: How so?
FRANK: My experiences with the epistemologist have been thoroughly unnerving! At this point I wonder if I may be going crazy; I can't even have confidence in how things appear to me. I think maybe you could be helpful here.
DOCTOR: I would be happy to but cannot for a while. For the next three months I am unbelievably overloaded with work. After that, unfortunately, I must go on a three-month vacation. So in six months come back and we can talk this over.
Scene 5. (Same office, six months later.)
DOCTOR: Before we go into your problems, you will be happy to hear that your friend the epistemologist is now completely recovered.
FRANK: Marvelous, how did it happen?
DOCTOR: Almost, as it were, by a stroke of fate-and yet his very mental activities were, so to speak, part of the "fate." What happened was this: For months after you last saw him, he went around worrying "should I trust the machine, shouldn't I trust the machine, should I, shouldn't, I, should I, shouldn't I." (He decided to use the word "should" in your empirical sense.) He got nowhere! So he then

decided to "formalize" the whole argument. He reviewed his study of symbolic logic, took the axioms of first-order logic, and added as nonlogical axioms certain relevant facts about the machine. Of course the resulting system was inconsistent-he formally proved that he should trust the machine if and only if he shouldn't, and hence that he both should and should not trust the machine. Now, as you may know, in a system based on classical logic (which is the logic he used), if one can prove so much as a single contradictory proposition, then one can prove any proposition, hence the whole system breaks down. So he decided to use a logic weaker than classical logic-a logic close to what is known as "minimal logic"-in which the proof of one contradiction does not necessarily entail the proof of every proposition. However, this system turned out too weak to decide the question of whether or not he should trust the machine. Then he had the following bright idea. Why not use classical logic in his system even though the resulting system is inconsistent? Is an inconsistent system necessarily useless? Not at all! Even though given any proposition, there exists a proof that it is true and another proof that it is false, it may be the case that for any such pair of proofs, one of them is simply more psychologically convincing than the other, so simply pick the proof you actually believe! Theoretically the idea turned out very well-the actual system he obtained really did have the property that given any such pair of proofs, one of them was always psychologically far more convincing than the other. Better yet, given any pair of contradictory propositions, all proofs of one were more convincing than any proof of the other. Indeed, anyone except the epistemologist could have used the system to decide whether the machine could be trusted. But with the epistemologist, what happened was this: He obtained one proof that he should trust the machine and another proof that he should not. Which proof was more convincing to him, which proof did he really "believe"? The only way he could find out was to consult the machine! But he realized that this would be begging the question, since his consulting the machine would be a tacit admission that he did in fact trust the machine. So he still remained in a quandary.
FRANK: So how did he get out of it?
DOCTOR: Well, here is where fate kindly interceded. Due to his absolute absorption in the theory of this problem, which consumed about his every waking hour, he became for the first time in his life experimentally negligent. As a result, quite unknown to him, a few minor units

of his machine blew out! 'Then, for the first time, the machine started giving contradictors information-not merely subtle paradoxes, but blatant contradictions. In particular. the ma machine one day claimed that the epistemologist believed a certain proposition and a few days later claimed he did not believe that proposition. And to add insult t , 1111th,, the machine claimed that he had not changed his belief in the last few days. This was enough to simply make him totally distrust the machine. Now he is fit as a fiddle.
FRANK This is certainly the most amazing thing I have ever heard! I guess the machine was really dangerous and unreliable all along.
DOCTOR: Oh, not at all: the machine used to be excellent before the epistemologist's experimental carelessness put it out of whack.
FRANK: Well, surely when I knew it, it couldn't have been very reliable.
DOCTOR: Not so, Frank, and this brings us to your problem. I know about your entire conversation with the epistemologist-it was all tape-recorded.
FRANK: Then surely you realize the machine could not have been right when it denied that I believed the book was red.
DOCTOR:: Why not?
FRANK: Good God, do 1 have to go through all this nightmare again? I can understand that a person can be wrong if he claims that a certain physical object has a certain property, but have you ever known a ,iugle case when a person can be mistaken when lie claims to have ()r- not have a certain sensation?
DOCTOR: Why, certainly! I once knew a Christian Scientist who had a raging toothache; he was frantically groaning and moaning all over the place. When asked whether a dentist might not cure him, he replied that there was nothing to be cured. Then he was asked, "But do you not feel pain?" He replied, "No, I do not feel pain; nobody feels pain, there is no such thing as pain, pain is only an illusion." So here is a case of a man who claimed not to feel pain, yet everyone present knew perfectly well that he did feel pain. I certainly don't believe he was lying, he was just simply mistaken.
RANK: Well, all right, in a case like that. But how can one be mistaken if one asserts his belief about the color of a hook?
DOCTOR: I can assure you that without access to any machine, if I asked someone what color is this book. and he answered. "I believe it is

red," I would be very doubtful that he really believed it. It seems me that if he really believed it, he would answer, "It is red" and n "I believe it is red" or "It seems red to me." The very timidity of h response would be indicative of his doubts.
FRANK: But why on earth should I have doubted that it was red?
DOCTOR:. You should know that better than I. Let us see now, have yont ever in the past had reason to doubt the accuracy of your sense perception?
FRANK: Why, yes. A few weeks before visiting the epistemologist, I suff o ered from an eye disease, which did make me see colors falsely. Bu I was cured before my visit.
DOCTOR: Oh, so no wonder you doubted it was red! True enough, your eyes perceived the correct color of the book, but your earlier experience lingered in your mind and made it impossible for you to really believe it was red. So the machine was right!
FRANK: Well, all right, but then why did I doubt that I believed it was true?
DOCTOR: Because you didn't believe it was true, and unconsciously you were smart enough to realize the fact. Besides, when one starts doubting one's own sense perceptions, the doubt spreads like an infection to higher and higher levels of abstraction until finally the whole belief system becomes one doubting mass of insecurity. I bet that if you went to the epistemologist's office now, and if the machine were repaired, and you now claimed that you believe the book is red, the machine would concur.

No, Frank, the machine is-or, rather, was-a good one. The epistemologist learned much from it, but misused it when he applied it to his own brain. He really should have known better than to create such an unstable situation. The combination of his brain and the machine each scrutinizing and influencing the behavior of the other led to serious problems in feedback. Finally the whole system went into a cybernetic wobble. Something was bound to give sooner or later. Fortunately, it was the machine.
FRANK: I see. One last question, though. How could the machine be trustworthy when it claimed to be untrustworthy?
DOCTOR: The machine never claimed to be untrustworthy, it only claimed that the epistemologist would be better off not trusting it. And the machine was right.

Raymond M. Smullyan

Reflections

If Smullyan's nightmare strikes you as too outlandish to be convincing, consider a more realistic fable-not a true story, but surely possible:
Once upon a time there were two coffee tasters, Mr. Chase and Mr. Sanborn, who worked for Maxwell House. Along with half a dozen other coffee tasters, their job was to ensure that the taste of Maxwell House stayed constant, year after year. One day, about six years after Mr. Chase had come to work for Maxwell House, he cleared his throat and confessed to Mr. Sanborn:
"You know, I hate to admit it, but I'm not enjoying this work any more. When I came to Maxwell House six years ago, I thought Maxwell House coffee was the best-tasting coffee in the world. I was proud to have a share in the responsibility for preserving that flavor over the years. And we've done our job well; the coffee tastes today just the way it tasted when .1 arrived. But, you know, I no longer like it! My tastes have changed. I've become a more sophisticated coffee drinker. I no longer like that taste at all."
Sanborn greeted this revelation with considerable interest. "It's funny you should mention it," he replied, "for something rather similar has happened to me. When I arrived here, shortly before you did, I, like you, thought Maxwell House coffee was tops in flavor. And now I, like you, really don't care for the coffee we're making. But my tastes haven't changed; my ... tasters have changed. That is, I think something has gone wrong with my taste buds or something-you know, the way your taste buds go off when you take a bite of pancakes and maple syrup and then go back to your orange juice? Maxwell House coffee doesn't taste to me the way it used to taste; if only it did, I'd still love it, for I still think that taste is the best taste in coffee. Now, I'm not saying we haven't done our job well. You other guys all agree that the taste is the same, so it must be my problem alone. I guess I'm no longer cut out for this work."
Chase and Sanborn are alike in one way. Both used to like Maxwell House coffee; now neither one likes it. But they claim to be different in

another way: Maxwell House tastes to Chase the way it always d but not so for Sanborn. The difference seems familiar and striking, y when they confront each other, they may begin to wonder if the' cases are really all that different. "Could it be," Chase might won der, "that Mr. Sanborn is really in my predicament and just hash' noticed the gradual rise in his standards and sophistication as a coffee taster?" "Could it be, Sanborn might wonder, "that Mr. Chase is kidding himself when he says the coffee tastes just the same to him as it used to?"
Do you remember your first sip of beer? Terrible! How could anyone like that stuff? But beer, you reflect, is an acquired taste; one gradually trains oneself-or just comes-to enjoy that flavor. What flavor? The flavor of that first sip? No one could like that flavor! Beer tastes different to the experienced beer drinker. Then beer isn't an acquired taste; one, doesn't learn to like that first taste; one gradually comes to experience a different, and likable, taste. Had the first sip tasted that way, you would have liked beer wholeheartedly from the beginning!
Perhaps, then, there is no separating the taste from the response to the taste, the judgment of good or bad. Then Chase and Sanborn might be just alike, and simply be choosing slightly different ways of expressing themselves. But if they were just alike, then they'd actually both be wrong about something, for they each have sincerely denied that they are like the other. Is, it conceivable that each could have inadvertently misdescribed his own case and described the other's instead? Perhaps Chase' is the one whose taste buds have changed, while Sanborn is the sophisticate. Could they be that wrong?
Some philosophers-and other people-have thought that a person simply cannot be wrong about such a matter. Everyone is the final and unimpeachable arbiter of how it is with him; if Chase and Sanborn have spoken sincerely, and have made no unnoticed slips of language, and if both know the meanings of their words, they must have expressed the truth in each case. Can't we imagine tests that would tend to confirm their different tales? If Sanborn does poorly on discrimination tests he used to pass with flying colors, and if, moreover, we find abnormalities in his taste buds (it's all that Szechuan food he's been eating lately, we discover), this will tend to confirm his view of his situation. And if Chase passes all those tests better than he used to, and exhibits increased knowledge of coffee types and a great interest in their relative merits and peculiar characteristics, this will support his view of himself. But if such tests could support Chase's and Sanborn's authority, failing them would have to undermine their

authority. If Chase passed Sanborn's tests and Sanborn passed Chase's, each would have doubt cast on his account-if such tests have any bearing at all on the issue.
Another way of putting the point is that the price you pay for the possibility of confirming your authority is the outside chance of being discredited. "I know what I like," we are all prepared to insist, "and I know what it's like to be me!" Probably you do, at least about some matters, but that is something to be checked in performance. Maybe, just maybe, you'll discover that you really don't know as much as you thought
you did about what it is like to be you.

D.C.D.

Chapter 24: What Is It Like to Be a Bat?

2007-02-14T05:56:00.002-08:00

Consciousness is what makes the mind-body problem really intractable. Perhaps that is why current discussions of the problem give it little attention or get it obviously wrong. The recent wave of reductionist euphoria has produced several analyses of mental phenomena and mental concepts designed to explain the possibility of some variety of materialism, psychophysical identification, or reduction.* But the problems dealt with are those common to this type of reduction and other types, and what makes the mind-body problem unique, and unlike the water-H20 problem or the Turing machine-IBM machine problem or the lightning-electrical discharge problem or the gene-DNA problem or the oak tree-hydrocarbon problem, is ignored.
Every reductionist has his favorite analogy from modern science. It is most unlikely that any of these unrelated examples of successful reduction will shed light on the relation of mind to brain. But philosophers share the general human weakness for explanations of what is incomprehensible in terms suited for what is familiar and well understood, though entirely different. This has led to the acceptance of implausible accounts of the mental largely because they would permit familiar kinds of reduction. I shall try to explain why the usual examples do not help us to understand the relation between mind and body-why, indeed, we have at present no conception of what an explanation of the physical nature

"What Is It Like to Be a Bat?" by Thomas Nagel appeared in The Philosophical Review, October 1974. It is reprinted by permission of the author.

*See "Further Reading" for Nagel's references.

of a mental phenomenon would be. Without consciousness the min body problem would be much less interesting. With consciousness seems hopeless. The most important and characteristic feature of conscious mental phenomena is very poorly understood. Most reductionist, theories do not even try to explain it. And careful examination will show that no currently available concept of reduction is applicable to it. Per. Naps a new theoretical form can be devised for the purpose, but such. solution, if it exists, lies in the distant intellectual future.
Conscious experience is a widespread phenomenon. It occurs a many levels of animal life, though we cannot be sure of its presence in the simpler organisms, and it is very difficult to say in general what provides evidence of it. (Some extremists have been prepared to deny it even of mammals other than man.) No doubt it occurs in countless forms totally unimaginable to us, on other planets in other solar systems throughout the universe. But no matter how the form may vary, the fact that an organism has conscious experience at all means, basically, that there is something it is like to be that organism. There may be further implications about the form of the experience; there may even (though I doubt it) be implications about the behavior of the organism. But fundamentally an organism has conscious mental states if and only if there is something that it is like to be that organism-something it is like for the organism.
We may call this the subjective character of experience. It is not captured by any of the familiar, recently devised reductive analyses of the mental, for all of them are logically compatible with its absence. It is no analyzable in terms of any explanatory system of functional states, or intentional states, since these could be ascribed to robots or automata that behaved like people though they experienced nothing.* It is no analyzable in terms of the causal role of experiences in relation to typical,,' human behavior-for similar reasons I do not deny that conscious mental states and events cause behavior, nor that they may be given functional characterizations. I deny only that this kind of thing exhausts their analysis. Any reductionist program has to be based on an analysis of what is to be reduced. If the analysis leaves something out, the problem will be falsely posed. It is useless to base the defense of materialism on any analysis of mental phenomena that fails to deal explicitly with their

*Perhaps there could not actually be such robots. Perhaps anything complex enough to behave like a person would have experiences. But that, if true, is a fact which cannot be discovered merely by analyzing the concept of experience.

It is not equivalent to that about which we are incorrigible, both because we are not incorrigible about experience and because experience is present in animals lacking language and thought, who have no beliefs at all about their experiences.

subjective character. For there is no reason to suppose that a reduction which seems plausible when no attempt is made to account for consciousness can be extended to include consciousness. Without some idea, therefore, of what the subjective character of experience is, we cannot know what is required of physicalist theory.
While an account of the physical basis of mind must explain many things, this appears to be the most difficult. It is impossible to exclude the phenomenological features of experience from a reduction in the same way that one excludes the phenomenal features of an ordinary substance from a physical or chemical reduction of it-namely, by explaining them as effects on the minds of human observers (cf. Rorty 1965). If physicalism is to be defended, the phenomenological features must themselves be given a physical account. But when we examine their subjective character it seems that such a result is impossible. The reason is that every subjective phenomenon is essentially connected with a single point of view, and it seems inevitable that an objective, physical theory will abandon that point of view.
Let me first try to state the issue somewhat more fully than by referring to the relation between the subjective and the objective, or between the pour soi and the en soi. This is far from easy. Facts about what it is like to be an X are very peculiar, so peculiar that some may be inclined to doubt their reality, or the significance of claims about them. To illustrate the connection between subjectivity and a point of view, and to make evident the importance of subjective features, it will help to explore the matter in relation to an example that brings out clearly the divergence between the two types of conception, subjective and objective.
I assume we all believe that bats have experience. After all, they are mammals, and there is no more doubt that they have experience than that mice or pigeons or whales have experience. I have chosen bats instead of wasps or flounders because if one travels too far down the phylogenetic tree, people gradually shed their faith that there is experience there at all. Bats, although more closely related to us than those other species, nevertheless present a range of activity and a sensory apparatus so different from ours that the problem I want to pose is exceptionally vivid (though it certainly could be raised with other species). Even without the benefit of philosophical reflection, anyone who has spent some time in an enclosed space with an excited bat knows what it is to encounter a fundamentally alien form of life.
I have said that the essence of the belief that bats have experience is that there is something that it is like to be a bat. Now we know that most bats (the microchiroptera, to be precise) perceive the external world primarily by sonar, or echolocation, detecting the reflections, from ob-

jects within range, of their own rapid, subtly modulated, high-frequen shrieks. Their brains are designed to correlate the outgoing impulse with the subsequent echoes, and the information thus acquired enables bats to make precise discriminations of distance, size, shape, motion, an texture comparable to those we make by vision. But bat sonar, though' clearly a form of perception, is not similar in its operation to any sense that we possess, and there is no reason to suppose that it is subjectively like anything we can experience or imagine. This appears to create difficulties for the notion of what it is like to be a bat. We must consider, whether any method will permit us to extrapolate to the inner life of the bat from our own case,* and if not, what alternative methods there ma be for understanding the notion.
Our own experience provides the basic material for our imagination whose range is therefore limited. It will not help to try to imagine that one has webbing on one's arms, which enables one to fly around at dusk and dawn catching insects in one's mouth; that one has very poor vision, and perceives the surrounding world by a system of reflected high-frequency sound signals; and that one spends the day hanging upside down by one's feet in an attic. Insofar as I can imagine this (which is not very far), it tells me only what it would be like for me to behave as a bat behaves. But that is not the question. I want to know what it is like for a bat to be a bat. Yet if I- try to imagine this, I am restricted to the resources of my own mind, and those resources are inadequate to the task. I cannot perform it either by imagining additions to my present experience, or by imagining segments gradually subtracted from it, or by imagining some combination of additions, subtractions, and modifications.
To the extent that I could look and behave like a wasp or a bat without changing my fundamental structure, my experiences would not be anything like the experiences of those animals. On the other hand, it is doubtful that any meaning can be attached to the supposition that I should possess the internal neurophysiological constitution of a bat. Even if I could by gradual degrees be transformed into a bat, nothing in my present constitution enables me to imagine what the experiences of such a future stage of myself thus metamorphosed would be like. The best evidence would come from the experiences of bats, if we only knew what they were like.
So if extrapolation from our, own case is involved in the idea of what it is like to be a bat, the extrapolation must be incompletable. We cannot

*By "our own case" I do not mean just "my own case," but rather the mentalistic ideas that we apply unproblematically to ourselves and other human beings.

form more than a schematic conception of what it is like. For example, we may ascribe general types of experience on the basis of the animal's structure and behavior. Thus we describe bat sonar as a form of three-dimensional forward perception; we believe that bats feel some versions of pain, fear, hunger, and lust, and that they have other, more familiar types of perception besides sonar. But we believe that these experiences also have in each case a specific subjective character, which it is beyond our ability to conceive. And if there is conscious life elsewhere in the universe, it is likely that some of it will not be describable even in the most general experiential terms available to us.* (The problem is not confined to exotic cases, however, for it exists between one person and another. The subjective character of the experience of a person deaf and blind from birth is not accessible to me, for example, nor presumably is mine to him. This does not prevent us each from believing that the other's experience has such a subjective character.)
If anyone is inclined to deny that we can believe in the existence of facts like this whose exact nature we cannot possibly conceive, he should reflect that in contemplating the bats we are in much the same position that intelligent bats or Martianst would occupy if they tried to form a conception of what it was like to be us. The structure of their own minds might make it impossible for them to succeed, but we know they would be wrong to conclude that there is not anything precise that it is like to be us: that only certain general types of mental state could be ascribed to us (perhaps perception and appetite would be concepts common to us both; perhaps not). We know they would be wrong to draw such a skeptical conclusion because we know what it is like to be us. And we know that while it includes an enormous amount of variation and complexity, and while we do not possess the vocabulary to describe it adequately, its subjective character is highly specific, and in some respects describable in terms that can be understood only by creatures like us. The fact that we cannot expect ever to accommodate in our language a detailed description of Martian or bat phenomenology should not lead us to dismiss as meaningless the claim that bats and Martians have experiences fully comparable in richness of detail to our own. It would be fine if someone were to develop concepts and a theory that enabled us to think about those things; but such an understanding may be permanently denied to us by the limits of our nature. And to deny the reality or logical significance of what we can never

*Therefore the analogical form of the English expression "what it is like" is misleading. It does not mean "what (in our experience) it resembles,“ but rather "how it is for the subject himself."

Any intelligent extraterrestrial beings totally different from us.

describe or understand is the crudest form of cognitive dissonance
This brings us to the edge of a topic that requires much more discussion than I can give it here: namely, the relation between facts on the one hand and conceptual schemes or systems of representation on the other. My realism about the subjective domain in all its forms implies a belief in the existence of facts beyond the reach of human concepts. Certainly it is possible for a human being to believe that there are facts which humans never will possess the requisite concepts to represent or comprehend. Indeed, it would be foolish to doubt this, given the finiteness of humanity's expectations. After all, there would have been transfinite numbers even if everyone had been wiped out by the Black Death before Cantor discovered them. But one might also believe that there are facts which could not ever be represented or comprehended by human beings, even if the species lasted forever-simply because our structure does not permit us to operate with concepts of the requisite type. This impossibility might even be observed by other beings, but it is not clear that the existence of such beings, or the possibility of their existence, is a precondition of the significance of the hypothesis that there are humanly inaccessible facts. (After all, the nature of beings with access to humanly inaccessible facts is presumably itself a humanly inaccessible fact.) Reflection on what it is like to be a bat seems to lead us, therefore, to the conclusion that there are facts that do not consist in the truth of propositions expressible in a human language. We can be compelled to recognize the existence of such facts without being able to state or comprehend' them.
I shall not pursue this subject, however. Its bearing on the topic before us (namely, the mind-body problem) is that it enables us to make a general observation about the subjective character of experience. Whatever may be the status of facts about what it is like to be a human being, or a bat, or a Martian, these appear to be facts that embody a particular point of view.
I am not adverting here to the alleged privacy of experience to its possessor. The point of view in question is not one accessible only to a single individual. Rather it is a type. It is often possible to take up a point of view other than one's own, so the comprehension of such facts is not limited to one's own case. There is a sense in which phenomenological facts are perfectly objective: One person can know or say of another what the quality of the other's experience is. They are subjective, however, in the sense that even this objective ascription of experience is possible only for someone sufficiently similar to the object of ascription to be able to adopt his point of view-to understand the ascription in the first person as well as in the third, so to speak. The more different from oneself the

other experiencer is, the less success one can expect with this enterprise. In our own case we occupy the relevant point of view, but we will have as much difficulty understanding our own experience properly if we approach it from another point of view as we would if we tried to understand the experience of another species without taking up its point of view.*
This bears directly on the mind-body problem. For if the facts of experience-facts about what it is like for the experiencing organism-are accessible only from one point of view, then it is a mystery how the true character of experiences could be revealed in the physical operation of that organism. The latter is a domain of objective facts par excellence the kind that can be observed and understood from many points of view and by individuals with differing perceptual systems. There are no comparable imaginative obstacles to the acquisition of knowledge about bat neurophysiology by human scientists, and intelligent bats or Martians might learn more about the human brain than we ever will.
This is not by itself an argument against reduction. A Martian scientist with no understanding of visual perception could understand the rainbow, or lightning, or clouds as physical phenomena, though he would never be able to understand the human concepts of rainbow, lightning, or cloud, or the place these things occupy in our phenomenal world. The objective nature of the things picked out by these concepts could be apprehended by him because, although the concepts themselves are connected with a particular point of view and a particular visual phenomenology, the things apprehended from that point of view are not: they are observable from the point of view but external to it; hence they can be comprehended from other points of view also, either by the same organisms or by others. Lightning has an objective character that is not exhausted by its visual appearance, and this can be investigated by a Martian without vision. To be precise, it has a more objective character than is revealed in its visual appearance. In speaking of the move from subjective to objective characterization, I wish to remain noncommittal about the existence of an end point, the completely objective intrinsic

*It may be easier than I suppose to transcend interspecies barriers with the aid of the imagination. For example, blind people are able to detect objects near them by a form of sonar, using vocal clicks or taps of a cane. Perhaps if one knew what that was like, one could by extension imagine roughly what it was like to possess the much more refined sonar of a bat. The distance between oneself and other persons and other species can fall anywhere on a continuum. Even for other persons the understanding of what it is like to be them is only partial, and when one moves to species very different from oneself, a lesser degree of partial understanding may still be available. The imagination is remarkably flexible. My point, however, is not that we cannot know what it is like to be a bat. I am not raising that epistemological problem. My point is rather that even to form a conception of what it is like to be a bat (and a fortiori to know what it is like to be a bat) one must take up the bat's point of view. If one can take it up roughly, or partially, then one's conception will also be rough or partial. Or so it seems in our present state of understanding.

nature of the thing, which one might or might not be able to reach. It may be more accurate to think of objectivity as a direction in which the under standing can travel. And in understanding a phenomenon like lightning it is legitimate to go as far away as one can from a strictly human viewpoint. *
In the case of experience, on the other hand, the connection with particular point of view seems much closer. It is difficult to understand what could be meant by the objective character of an experience, apart from the particular point of view from which its subject apprehends it. After all, what would be left of what it was like to be a bat if one removed the viewpoint of the bat? But if experience does not have, in addition to its subjective character, an objective nature that can be apprehended from many different points of view, then how can it be supposed that a, Martian investigating my brain might be observing physical processes which were my mental processes (as he might observe physical processes which were bolts of lightning), only from a different point of view? How, for that matter, could a human physiologist observe them from another point of view?
We appear to be faced with a general difficulty about psychophysical reduction. In other areas the process of reduction is a move in the direction of greater objectivity, toward a more accurate view of the real nature of things. This is accomplished by reducing our dependence on individual or species-specific points of view toward the object of investigation We describe it not in terms of the impressions it makes on our senses, but in terms of its more general effects and of properties detectable 'b means other than the human senses. The less it depends on a specifically human viewpoint, the more objective is our description. It is possible to follow this path because although the concepts and ideas we employ in thinking about the external world are initially applied from a point of view that involves our perceptual apparatus, they are used by us to refer to things beyond themselves-toward which we have the phenomenal point of view. Therefore we can abandon it in favor of another, and still be thinking about the same things.
Experience itself, however, does not seem to fit the pattern. The idea

*The problem I am going to raise can therefore be posed even if the distinction between more subjective and more objective descriptions or viewpoints can itself be made only within a larger human point of view. I do not accept this kind of conceptual relativism, but it need not be refuted to make the point that psychophysical reduction cannot be accommodated by the subjective-to-objective model familiar from other cases.

The problem is not just that when I look at the Mona Lisa, my visual experience has a certain quality, no trace of which is to be found by someone looking into my brain. For even if he did observe there a tiny image of the Mona Lisa, he would have no reason to identify it with the experience.

of moving from appearance to reality seems to make no sense here. What is the analogue in this case to pursuing a more objective understanding of the same phenomena by abandoning the initial subjective viewpoint toward them in favor of another that is more objective but concerns the same thing? Certainly it appears unlikely that we will get closer to the real nature of human experience by leaving behind the particularity of our human point of view and striving for a description in terms accessible to beings that could not imagine what it was like to be us. If the subjective character of experience is fully comprehensible only from one point of view, then any shift to greater objectivity-that is, less attachment to a specific viewpoint-does not take us nearer to the real nature of the phenomenon: It takes us farther away from it.
In a sense, the seeds of this objection to the reducibility of experience are already detectable in successful cases of reduction; for in discovering sound to be, in reality, a wave phenomenon in air or other media, we leave behind one viewpoint to take up another, and the auditory, human or animal viewpoint that we leave behind remains unreduced. Members of radically different species may both understand the same physical events in objective terms, and this does not require that they understand the phenomenal forms in which those events appear to the senses of members of the other species. Thus it is a condition of their referring to a common reality that their more particular viewpoints are not part of the common reality that they both apprehend. The reduction can succeed only if the species-specific viewpoint is omitted from what is to be reduced.
But while we are right to leave this point of view aside in seeking a fuller understanding of the external world, we cannot ignore it permanently, since it is the essence of the internal world, and not merely a point of view on it. Most of the neobehaviorism of recent philosophical psychology results from the effort to substitute an objective concept of mind for the real thing, in order to have nothing left over which cannot be reduced. If we acknowledge that a physical theory of mind must account for the subjective character of experience, we must admit that no presently available conception gives us a clue how this could be done. The problem is unique. If mental processes are indeed physical processes, then there is something it is like, intrinsically,* to undergo certain physical pro

*The relation would therefore not be a contingent one, like that of a cause and its distinct effect. It would be necessarily true that a certain physical state felt a certain way. Kripke (1972) argues that causal behaviorist and related analyses of the mental fail because they construe, for example, "pain" as a merely contingent name of pains. The subjective character of an experience ("its immediate phenomenological quality," Kripke calls it [p. 340]) is the essential property left out by such analyses, and the one in virtue of which it is, necessarily, the experience it is. My view is closely related to his. Like Kripke, I find the hypothesis that a certain brain state should necessarily have a certain subjective character

cesses. What it is for such a thing to be the case remains a mystery
What moral should be drawn from these reflections, and what should be done next? It would be a mistake to conclude that physicalism mu be false. Nothing is proved by the inadequacy of physicalist hypothesis that assume a faulty objective analysis of mind. It would be truer tcp say that physicalism is a position we cannot understand because we do not at present have any conception of how it might be true. Per haps it will be thought unreasonable to require such a conception as a condition of understanding. After all, it might be said, the meaning of physicalism is clear enough: mental states are states of the body, mental events are physical events. We do not know which physical states and events they are, but that should not prevent us from undo standing the hypothesis. What could be clearer than the words "is and "are"?
But I believe it is precisely this apparent clarity of the word "is" that is deceptive. Usually, when we are told that X Is Y we know how it is supposed to be true, but that depends on a conceptual or theoretical background and is not conveyed by the "is" alone. We know how both -X" and "Y" refer, and the kinds of things to which they refer, and we, have a rough idea how the two referential paths might converge on a single thing, be it an object, a person, a process, an event or whatever.. But when the two terms of the identification are very disparate it may not

incomprehensible without further explanation. No such explanation emerges from theories which view the mind-brain relation as contingent, but perhaps there are other alternatives, not yet discovered.
A theory that explained how the mind-brain relation was necessary would still leave us with Kripke's problem of explaining why it nevertheless appears contingent. That difficult seems to me surmountable, in the following way. We may imagine something by representing it to ourselves either perceptually, sympathetically, or symbolically. I shall not try to say how symbolic imagination works, but part of what happens in the other two cases is this. To imagine something perceptually, we put ourselves in a conscious state resembling the state we would be in if we perceived it. To imagine something sympathetically, we put ourselves in a conscious state resembling the thing itself. (This method can be used only to imagine mental events and states-our own or another's.) When we try to imagine a mental state occurring without its associated brain state, we first sympathetically imagine the occurrence of the mental state: that is, we put ourselves into a state that resembles it mentally. At the same time, we attempt perceptually to imagine the nonoccurrence of the associated physical state, by putting ourselves into another state unconnected with the first: one resembling that which we would be in if we perceived the nonoccurrence of the physical state. Where the imagination of physical features is perceptual and the imagination of mental features is sympathetic, it appears to us that we can imagine any experience occurring without its associated brain state, and vice versa. The relation between them will appear contingent even if it is necessary, because of the independence of the disparate types of imagination.
(Solipsism, incidentally, results if one misinterprets sympathetic imagination as if it worked like perceptual imagination: It then seems impossible to imagine any experience that is not one's own.)

be so clear how it could be true. We may not have even a rough idea of how the two referential paths could converge, or what kind of things they might converge on, and a theoretical framework may have to be supplied to enable us to understand this. Without the framework, an air of mysticism surrounds the identification.
This explains the magical flavor of popular presentations of fundamental scientific discoveries, given out as propositions to which one must subscribe without really understanding them. For example, people are now told at an early age that all matter is really energy. But despite the fact that they know what "is" means, most of them never form a conception of what makes this claim true, because they lack the theoretical background.
At the present time the status of physicalism is similar to that which the hypothesis that matter is energy would have had if uttered by a pre-Socratic philosopher. We do not have the beginnings of a conception of how it might be true. In order to understand the hypothesis that a mental event is a physical event, we require more than an understanding of the word "is." The idea of how a mental and a physical .term might refer to the same thing is lacking, and the usual analogies with theoretical identification in other fields fail to supply it. They fail because if we construe the reference of mental terms to physical events on the usual model, we either get a reappearance of separate subjective events as the effects through which mental reference to physical events is secured, or else we get a false account of how mental terms refer (for example, a causal behaviorist one).
Strangely enough, we may have evidence for the truth of something we cannot really understand. Suppose a caterpillar is locked in a sterile safe by someone unfamiliar with insect metamorphosis, and weeks later the safe is reopened, revealing a butterfly. If the person knows that the safe has been shut the whole time, he has reason to believe that the butterfly is or was once the caterpillar, without having any idea in what sense this might be so. (One possibility is that the caterpillar contained a tiny winged parasite that devoured it and grew into the butterfly.)
It is conceivable that we are in such a position with regard to physicalism. Donald Davidson has argued that if mental events have physical causes and effects, they must have physical descriptions. He holds that we have reason to believe this even though we do not-and in fact could not -have a general psychophysical theory.* His argument applies to intentional mental events, but I think we also have some reason to believe that

*See Davidson (1970); though I do not understand the argument against psychophysical
laws.

sensations are physical processes, without being in a position to unde stand how. Davidson's position is that certain physical events have irreducibly mental properties, and perhaps some view describable in this way is correct. But nothing of which we can now form a conception corresponds to it; nor have we any idea what a theory would be like that enabled us to conceive of it.
Very little work has been done on the basic question (from which mention of the brain can be entirely omitted) whether any sense can be made of experiences' having an objective character at all. Does it make, sense, in other words, to ask what my experiences are really like, as~ opposed to how they appear to me? We cannot genuinely understand the hypothesis that their nature is captured in a physical description unless we understand the more fundamental idea that they have an objective nature (or that objective processes can have a subjective nature).t
I should like to close with a speculative proposal. It may be possible to approach the gap between subjective and objective from another direction. Setting aside temporarily the relation between the mind and th brain, we can pursue a more objective understanding of the mental in its own right. At present we are completely unequipped to think about the subjective character of experience without relying on the imagination without taking up the point of view of the experiential subject. This should be regarded as a challenge to form new concepts and devise a new method-an objective phenomenology not dependent on empathy or the imagination. Though presumably it would not capture everything, its goal would be to describe, at least in part, the subjective character o experiences in a form comprehensible to beings incapable of having those experiences.
We would have to develop such a phenomenology to describe th sonar experiences of bats; but it would also be possible to begin with humans. One might try, for example, to develop concepts that could be used to explain to a person blind from birth what it was like to see. One would reach a blank wall eventually, but it should be possible to devise a method of expressing in objective terms much more than we can at present, and with much greater precision. The loose intermodal analogies-for example, "Red is like the sound of a trumpet"-which crop up in discussions of this subject are of little use. That should be clear to anyone who has both heard a trumpet and seen red. But structural fea

*Similar remarks apply to Nagel (1965).

This question also lies at the heart of the problem of other minds, whose close connection with the mind-body problem is often overlooked. If one understood how subjective experience could have an objective nature, one would understand the existence of subjects other than oneself.

tures of perception might be more accessible to objective description, even though something would be left out. And concepts alternative to those we learn in the first person may enable us to arrive at a kind of understanding even of our own experience which is denied us by the very ease of description and lack of distance that subjective concepts afford.
Apart from its own interest, a phenomenology that is in this sense objective may permit questions about the physical* basis of experience to assume a more intelligible form. Aspects of subjective experience that admitted this kind of objective description might be better candidates for objective explanations of a more familiar sort. But whether or not this guess is correct, it seems unlikely that any physical theory of mind can be contemplated until more thought has been given to the general problem of subjective and objective. Otherwise we cannot even pose the mind-body problem without sidestepping it.

Thomas Nagel

Reflections

He does all the things that you would never do;
He loves me, too-His love is true.Why can't he be you?
-Hank Cochran, ca. 1955

Twinkle, twinkle, little bat,.
How I wonder what you're at,
Up above the world you fly,Like a tea-tray in the sky.
-Lewis Carroll, ca. 1865

There is a famous puzzle in mathematics and physics courses. It asks, "Why does a mirror reverse left and right, but not up and down?" It gives many people pause for thought, and if you don't want to be told the answer, skip the next two paragraphs.
The answer hinges on what we consider a suitable way to project ourselves onto our mirror images. Our first reaction is that by walking forward a few steps and then spinning' around on our heels, we could step into the shoes of "that person" there in the mirror-forgetting that the heart, appendix, and so forth of "that person" are on the wrong side. The

*1 have not defined the term "physical." Obviously it does not apply just to what can be described by the concepts of contemporary physics, since we expect further developments. Some may think there is nothing to prevent mental phenomena from eventually being recognized as physical in their own right. But whatever else may be said of the physical, it has to be objective. So if our idea of the physical ever expands to include mental phenomena, it will have to assign them an objective character-whether or not this is done by analyzing them in terms of other phenomena already regarded as physical. It seems to me more likely, however, that mental-physical relations will eventually be expressed in a theory whose fundamental terms cannot be placed clearly in either category.

language hemisphere of the brain is, in all probability, on the nonstandard side. On a gross anatomical level, that image is actually of a nonperson. Microscopically, the situation is even worse. The DNA molecules coil the wrong way, and the mirror-"person" could no more mate with a real person than could a nosrep!
But wait-you can get your heart to stay on the proper side if, instead, you flip yourself head over heels, as if swinging over a waist-high horizontal bar in front of you. Now your heart is on the same side as the mirror-person's heart-but your feet and head are in the wrong places, and your stomach, although at approximately the right height, is upsidedown. So it seems a mirror can be perceived as reversing up and down, provided you're willing to map yourself onto a creature whose feet are above its head. It all depends on the ways that you are willing to slip yourself onto another entity. You have a choice of twirling around a horizontal or a vertical bar, and getting the heart right but not the head and feet, or getting the head and feet right but not the heart. It's simply that, because of the external vertical symmetry of the human body, the vertical self-twirling yields a more plausible-seeming you-to-image mapping. But mirrors intrinsically don't care which way you interpret what they do. And in fact, all they really reverse is back and front!
There is something very beguiling about this concept of mapping, projection, identification, empathy-whatever you want to call it. It is a basic human trait, practically irresistible. Yet it can lead us down very strange conceptual pathways. The preceding puzzle shows the dangers of over facile self-projection. The refrain quoted from the country-western ballad reminds us more poignantly of the futility of taking such mapping too seriously. Yet we can't stop our minds from doing it. So since we can't, let's go whole hog and indulge ourselves in an orgy of extravagant variations on the theme set by Nagel in his title.

What is it like to work at McDonald's? To be thirty-eight? To be in London today?

What is it like to climb Mount Everest? To be an Olympic gold-medal winner in
gymnastics?

What would it be like to be a good musician? To be able to improvise fugues at
the keyboard? To be J. S. Bach? To be J. S. Bach writing the last movement of the Italian Concerto?

What is it like to believe the earth is flat?

What is it like to be someone inconceivably more intelligent than yourself?
Inconceivably less intelligent?

What is it like to hate chocolate (or your personal favorite flavor)?

What is it like to bat a bee? What is it like to be a bee being batted? What is it like to be a batted bee? (Illustration by Jim Hull.)

What is it like to hear English (or one's native language) without understanding tt?

What is it like to be of the opposite sex? (See selection 15, "Beyond Rejection")
What would it be like to be your mirror image? (See the movie Journey to the Far
Side o/ the Sun)

What would it be like to be Chopin's brother (he had none)? The present King of France?

What is it like to be a dreamed person? To be a dreamed person when the alarm rings? To be Holden Caulfield? To be the subsystem ofJ. D. Salinger's brain that represents the character of Holden Caulfield?

What is it like to be a molecule? A collection of molecules? A microbe? A mosquito? An ant? An ant colony? A beehive? China? The United States? Detroit? General Motors? A concert audience? A basketball team? A married couple? A two-headed cow? Siamese twins? A split-brain person? One half of a split-brain person? The head of a guillotined person? The body? The visual cortex of Picasso? The pleasure center of a rat? The jerking leg of a dissected frog? A bee's eye? A retinal cell in Picasso? A DNA molecule of Picasso?

What is it like to be a running Al program? An operating system in a computer? An operating system at the moment the system "crashes"?

What is it like to be under a general anesthetic? To be electrocuted? To be a Zen master who has attained a satori-like state in which no more subject ("I," ego, self) exists?

What is it like to be a pebble? A wind chime? A human body? The Rock of Gibraltar? The Andromeda Galaxy? God?

The image conjured up by the phrase "What is it like to be X"? IS so seductive and tempting.... Our minds are so flexible, so willing to accept this notion, this idea that there is "something it is, like to be a bat.' Furthermore, we also willingly buy the idea that there are certain things that it is "like something to be"-"be-able things," or "BATs" for short -such as bats, cows, people; and other things for which this doesn't hold -such as balls, steaks, galaxies (even though a galaxy may contain innumerable be-able things). What is the criterion for "BAT-itude"?
In philosophical literature, many phrases have been used to try to evoke the right flavors for what being sentient really is ("being sentient" is one of them). Two old terms are "soul" and "anima." These days, an "in" word is "intentionality." There is the old standby, "consciousness." Then there is "being a subject," "having an inner life," "having experience," "having a point of view," having "perceptual aboutness" or "personhood" or a "self" or "free will." In some people's eyes, "having a mind," "being intelligent," and just plain old "thinking" have the right flavors. In Searle's article (selection 22), the contrast was drawn between "form" (hollow and mechanical) and "content" (alive and intentional); the words "syntactic" and "semantic" (or "meaningless" and "meaningful") were also used to characterize this distinction. All of the terms in this huge showcase are nearly synonymous. They all have to do with the emotional issue of whether it makes sense to project ourselves onto the object in question: "Is this object a BAT, or not?" But is there really some thing to which they refer?
Nagel makes it clear that the "thing" he is after is a distillation of tha which is common to the experiences of all bats; it is not the set o experiences of some particular bat. Thus, Searle might say Nagel is a "dualist," since Nagel believes in some abstraction made from all those individuals' experiences.
Surprisingly enough, a look at the grammar of sentences that invite the reader to perform a mental mapping yields some insights into these tricky matters. Consider, for instance, the contrast between the questions "What would it be like to be Indira Gandhi?" and "What is it like to be Indira Gandhi?" The conditional sentence forces you to project yourself into the "skin," so to speak, of another human, whereas the indicative sentence seems to be asking what it is like for Indira Gandhi to be Indira Gandhi. The question might still be asked, "Described in whose terms?" Were Indira Gandhi to try to tell you what it is like to be Indira Gandhi, she might try to explain matters of political life in India by referring to things she considered vaguely analogous in your own experience. Would you protest and say, "No, don't translate it into my terms! Say it in your

own terms! Tell me what it is like-to Indira Gandhi-for Indira Gandhi to be Indira Gandhi!" In that case, of course, she might as well speak in Hindi and leave it to you to learn the language. And yet even then you would just be in the position of millions of native Hindi speakers who have no idea what it would be like to be Indira Gandhi-much less what it is like for Indira Gandhi to be Indira Gandhi....
Something seems very wrong here. Nagel is insistent that he wants his verb "be" to be subjectless, in effect. Not "What would it be like for me to be X"? but "What is it like, objectively, to be X?" There is a "be-ee" here, with no ; `be-er"-a living beast without a head, as it were. Perhaps we ought to go back to the conditional version: "What would it be like to be Indira Gandhi?" Well, for me, or for her? Poor Indira-where does she go while I'm being her? Or if we turn it around (identity being a symmetric relationship), we get "What would it be like for Indira Gandhi to be me?" Once again, where would I be if she were me? Would we have traded places? Or would we have temporarily collapsed two separate "souls" into one?
Note that we tend to say "If she were me" rather than "If she were I." Many European languages are somewhat skittish about equations of this type. It sounds funny to use the nominative case in both the subject and complement positions. People prefer to use "be" with the accusative case, as if it were somehow a transitive verb! "Be" is not a transitive verb, but a symmetric one-yet language tilts us away from that symmetric vision.
We can see this in German, where one has interesting alternatives for constructing such identity-asserting sentences. Two examples follow, adapted from the German translation of a Stanislaw Lem dialogue in which an exact molecule-for-molecule replica of a doomed person is about to be constructed. In that spirit, we provide (nearly) exact word-for-word replicas in English of the German originals:

1. Ob die Kopie wirklich du bist, dafur mul3 der Beweis noch erbracht werden.
(As-to-whether the copy really you are, thereof must the proof still provided be.)

2. Die Kopie wird behaupten, dab sie du ist. (The copy will claim that it you is.)

Observe that in both identity-asserting clauses, "the copy" (or "it") appears first, then "you," then the verb. But notice-in the first clause, "are" is the verb, which retroactively implies that "you" was the subject and "the copy" was the complement, whereas in the second clause, the verb is "is," retroactively implying that the subject was "it" and the

complement was "you." The fact that the verb comes at the end gives these clauses a sort of surprise-ending quality. In English we can't achieve precisely the same effect comfortably, but we can ask for the difference in shades of meaning between the sentences "Is the copy really you?" and "Are you really the copy?" These two questions "slip" in our minds along different dimensions. The former slips into "Or is the copy really some one else-or perhaps no one at all?" The latter slips into "Or are you somewhere else-or are you anywhere?" Our book's title, incidentally, can be construed not only as a possessive, but equally as a short full sentence reply to the two questions "Who am l?" and "Who is me?" Notice how the transitive usage-strictly speaking, an ungrammatical usage of "to be"-gives the second question a quite different "flavor" from the first.
[D.C.D. to D.R.H.: If I were you, I'd mention how curious it woul be to preface some advice with "If you were me, I'd ..." but if you were me, would I suggest that you mention it?]
All of these examples show how suggestible we are. We just fall like a ton of bricks for the notion that there's a "soul" in there-a flamelike soul that can flicker on or off, or even be transferred between bodies as a flame between candles. If a candle blows out and is relit, is it "the same flame"? Or, if it stays lit, is it even "the same flame" from moment to moment? The Olympic Torch is carefully kept burning as it is carried by runners thousands of miles from Athens to its destination every four years. There is powerful symbolism to the idea that this is "the very flame that was lit in Athens." Even the shortest break in the chain, however, would ruin the symbolism for people who knew. For people who didn't know, of course, no harm done! How on earth could it possibly matter? Yet emotionally it seems to. It will not easily be extinguished, that "soulflame" notion. Yet it leads us into so much hot water.
We certainly intuit that only things of approximately the "same-sized souls" can slip into each other. The science-fiction story Flowers for Algernon by Daniel Keyes is about a retarded young man who by a miracle medical treatment slowly gains in intelligence and becomes a great genius -but then it turns out that the effects of the treatment cannot last, and "he" witnesses his own mental crumbling back into his retarded state. This fictional story has its counterpart in the real-life tragedy of people who, having grown from a state of zero mind to normal adult intelligence, witness themselves growing senile or who suffer serious brain damage. Can they answer for us the question "What is it like to have your soul slip out from under you?" any better than someone with vivid imagination can, though?

Franz Kafka's Metamorpho sis is the story of a young man who wakes

up one morning transformed into a giant beetle. But the beetle thinks like a person. It would be interesting to combine the Flowers for Algernon idea with the Metamorphosis idea and imagine the experiences of an insect whose intelligence rises to the level of a human genius (why not superhuman, for that matter?), then sinks back to the insect level. Yet this is virtually impossible for us to conceive. To borrow electrical-engineering argon, the "impedance match" of the minds involved is too poor. In fact, impedance match may well be the main criterion for the plausibility of questions of the form Nagel poses. Which is it easier for you to imagine being-the totally fictional character Holden Caulfield or some particular, actual bat? Of course it is much easier to map yourself onto a fictional human than onto a real bat-much easier, much realer. This is slightly surprising. It seems that Nagel's verb "be" acts very strangely sometimes. Perhaps, as was suggested in the dialogue on the Turing test, the verb "be" is being extended. Perhaps it is even being stretched beyond its limits!
There's something very fishy about this whole idea. How can something be something that it isn't? And how is it rendered any more plausible when both things can "have experience"? It makes almost no sense for us to ask ourselves such questions as, "What would it be like for that black spider over there to be that mosquito trapped in its web?" Or worse yet, "What would it be like for my violin to be my guitar?" or "What would this sentence be like if it were a hippopotamus?" Like for whom? For the various objects concerned, sentient or not? For us the perceivers? Or, again, "objectively"?
This is the sticking-point of Nagel's article. He wants to know if it is possible to give, in his own words, "a description [of the real nature of human experience] in terms accessible to beings that could not imagine what it was like to be us." Put so starkly, it sounds like a blatant contradiction-and indeed, that is his point. He doesn't want to know what it's like for him to be a bat. He wants to know objectively what it is subjectively like. It wouldn't be enough for him to have had the experience of donning a "batter's helmet"-a helmet with electrodes that would stimulate his brain into batlike experiences-and to have thereby experienced "batitude." This would, after all, merely be what it would be like for Nagel to be a bat. What, then, would satisfy him? He's not sure that anything would, and that's what worries him. He fears that this notion of "having experience" is beyond the realm of the objective.
Now perhaps the most objective-sounding of the various synonyms earlier listed for BAT-itude is "having a point of view." After all, even the most dogmatic of disbelievers in machine intelligence would probably begrudgingly impute a "point of view" to a computer program that

represents some facts about the world and about its own relationship t the world. There is no arguing with the fact that a computer can b programmed to describe the world around it in terms of a frame of reference centered on the machine itself, as in this: "Three minutes ago, the Teddy bear was thirty-five leagues due east of here." Such a "here centered, now-centered" frame of reference constitutes a rudimentary "egocentric" point of view. "Being here now" is a central experience for any "I." Yet how can you define "now" and "here" without making reference to some "I"? Is circularity inevitable?
Let us ponder for a moment on the connection of "I" and `,now." What would it be like to be a person who had grown up normally, thus with ordinary perceptual and linguistic capacities, but who then suffered some brain damage and was left without the capacity to convert the reverberating neural circuits of short-term memory into long-term memories? Such a person's sense of existence would extend to only a few seconds on either side of "now." There would be no large-scale sense of continuity of self-no internal vision of a chain of selves stretching both directions in time, making one coherent person.
When you get a concussion, the few instants before it happened are obliterated from your mind, as if you had never been conscious at that time. Just think-if you were knocked on the head at this moment, there would be no permanent trace left in your brain of your having read these past few sentences. Who, then, has been experiencing them? Does an experience only become part of you once it has been committed to longterm memory? Who is it that has dreamt all those many dreams you don't remember one bit of?
Just as "now" and "I" are closely related terms, so are "here" and "I." Consider the fact that you are now experiencing death, in a curious way. Not being in Paris right now, you know what it is like to be dead in Paris. No lights, no sounds-nothing. The same goes for Timbuctu. In fact, you are dead everywhere-except for one small spot. Just think how close you are to being dead everywhere! And you are also dead in all other moments than right now. That one small piece of space-time you-are alive in doesn't just happen to be where your body is now-it is defined by your body and by the concept of "now." Our languages all have words that incorporate a rich set of associations with "here" and "now" namely, "I" and "me" and so on.
Now to program a computer to use words like "I" and "me" and "my" in describing its own relation to the world is a common thing. Of course, behind those words there need not stand any sophisticated self-concept-but there may. In essence, any physical representational system, as defined earlier in the commentary on the "Prelude, Ant Fugue"

(selection 11), is an embodiment of some point of view, however modest. This explicit connection between "having a point of view" and "being a representational system" now provides a step forward in thinking about BAT-itude, for if we can equate BATs with physical representational systems of sufficient richness in their repertoire of categories and sufficiently well-indexed memories of their worldlines, we will have objectified at least some of subjectivity.
It should be pointed out that what is strange about the idea of "being a bat" is not that bats sense the outside world in a bizarre way-it is that bats clearly have a highly reduced collection of conceptual and perceptual categories, compared to what we humans have. Sensory modalities are surprisingly interchangeable and equivalent, in some sense. For instance, it is possible to induce visual experiences in both blind and sighted people through the sensation of touch. A grid of over a thousand stimulators driven by a television camera is placed against a person's back. The sensations are carried to the brain where their processing can induce the having of visual experiences. A sighted woman reports on her experience of prosthetic vision:

I sat blindfolded in the chair, the TSR cones cold against my back. At first I felt only formless waves of sensation. Collins said he was just waving his hand in front of me so that I could get used to the feeling. Suddenly I felt or saw, I wasn't sure which, a black triangle in the lower left corner of a square. The sensation was hard to pinpoint. I felt vibrations on my back, but the triangle appeared in a square frame inside my head. (Nancy Hechinger, "Seeing Without Eyes," Science 81, March 1981, p. 43.)

Similar transcending of modality in sensory input is well known. As has been pointed out in earlier selections, people who wear prism-shaped glasses that turn everything upside down can, after two or three weeks, get quite used to seeing the world this way. And, on a more abstract plane, people who learn a new language still experience the world of ideas in pretty much the same way.
So it is really not the mode of transduction of stimuli into percepts or the nature of the thought-supporting medium that makes the "bat Weltanschauung" different from ours. It is the severely limited set of categories, together with the stress on what is important in life and what is not. It is the fact that bats cannot form notions such as "the human Weltanschauung" and joke about them, because they are too busy, always being in raw-survival mode.
What Nagel's question forces us to think about-and think very hard about-is how we can map our mind onto that of a bat. What kind of representational system is the mind of a bat? Can we empathize with a

bat? In this view, Nagel's question seems intimately connected to the wa in which one representational system emulates another, as discussed in the Reflections on selection 22. Would we learn something by asking a Sigma-5, "What is it like to be a DEC?" No, that would be a silly question. The reason it would be silly is this. An unprogrammed computer is not a representational system. Even when one computer has a program allow_ ing it to emulate another, this does not give it the representational power to deal with the concepts involved in such a question. For that it would need a very sophisticated AI program-one that, among other things, could use the verb "be" in all the ways we do (including Nagel's extended sense). The question to ask would be, rather, "What is it like for you, as a self-understanding Al program, to emulate another such program?" But then this question starts to resemble very strongly the question "What is it like for one person to empathize strongly with another?"
As we pointed out earlier, people do not have the patience or accuracy to emulate a computer for any length of time. When trying to put themselves in the shoes of other BATs, people tend to empathize, not to emulate. They "subvert" their own internal symbol systems by voluntarily adopting a global set of biases that modify the cascades of symbolic activity in their brains. It is not quite the same as taking LSD, although that too creates radical changes in the way that neurons communicate with one another. LSD does so unpredictably. Its effects depend on how it is spread about inside the brain, and that has nothing to do with what symbolizes what. LSD affects thought in somewhat the same way that having a bullet shot through your brain would affect thought-neither intrusive substance pays any regard to the symbolic power of the stuff in the brain.
But a bias established through symbolic channels-"Hey, let me think about how it would feel to be a bat"-sets up a mental context. Translated into less mentalistic and more physical terms, the act of trying to project yourself into a bat's point of view activates some symbols in your brain. These symbols, as long as they remain activated, will contribute to the triggering patterns of all the other symbols that are activated. And the brain is sufficiently sophisticated that it can treat certain activations as stable-that is, as contexts-and other symbols then are activated in a subordinate manner. So when we attempt to "think bat," we subvert our brains by setting up neural contexts that channel our thoughts along different pathways than they usually follow. (Too bad we can't just "think Einstein" when we want!)
All this richness, however, cannot get us all the way to batitude. Each person's self-symbol-the "personal nucleus," or "gemma" in Lem's personetics-has become, over his or her life, so large and complicated

and idiosyncratic that it can no longer, chameleonlike, just assume the identity of another person or being. Its individual history is just too wound up in that little "knot" of a self-symbol.
It is interesting to think about two systems that are so alike that they have isomorphic, or identical, self-symbols-say a woman and an atomby-atom replica of her. If she thinks about herself, is she also thinking about her replica? Many people fantasize that somewhere out there in the heavens, there is another person just like them. When you think about yourself, are you also thinking, without being aware of it, about that person? Who is that person thinking about right now? What would it be like to be that person? Are you that person? If you had a choice, would you let that person be killed, or yourself?
The one thing that Nagel seems not to have acknowledged in his article is that language (among other things) is a bridge that allows us to cross over into territory that is not ours. Bats don't have any idea of "what it is like to be another bat" and don't wonder about it, either. And that is because bats do not have a universal currency for the exchange of ideas, which is what language, movies, music, gestures, and so on give us. These media aid in our projection, aid us in absorbing foreign points of view. Through a universal currency, points of view become more modular, more transferable, less personal and idiosyncratic.
Knowledge is a curious blend of objective and subjective. Verbalizable knowledge can be passed around and shared, to the extent that words really "mean the same thing" to different people. Do two people ever speak the same language? What we mean by "speak the same language" is a prickly issue. We accept and take for granted that the hidden subterranean flavors are not shared. We know what comes with and what is left out of linguistic transactions, more or less. Language is a public medium for the exchange of the most private experiences. Each word is surrounded, in each mind, by a rich and inimitable cluster of concepts, and we know that no matter how much we try to bring to the surface, we always miss something. All we can do is approximate. (See George Steiner's After Babel for an extended discussion of this idea.)
By means of meme-exchange media (see selection 10, "Selfish Genes and Selfish Memes") such as language and gestures, we can experience (vicariously sometimes) what it is like to be or do X. It's never genuine, but then what is genuine knowledge of what it is like to be X? We don't even quite know what it was like to be ourselves ten years ago. Only by rereading diaries can we tell-and then, only by projection! It is still vicarious. Worse yet, we often don't even know how we could possibly have done what we did yesterday. And, when you come right down to it, it's not so clear just what it is like to be me, right now.

Language is what gets us into this problem (by allowing us to see th question) and what helps to get us out as well (by being a universal thought-exchange medium, allowing experiences to become sharable and more objective). However, it can't pull us all the way.
In a sense, Gödel’s Theorem is a mathematical analogue of the fact that I cannot understand what it is like not to like chocolate, or to be a bat, except by an infinite sequence of ever-more-accurate simulation processes that converge toward, but never reach, emulation. I am trapped inside myself and therefore can't see how other systems are. Gödel’s Theorem follows from a consequence of that general fact: I am trapped inside myself and therefore can't see how other systems see me. Thus the objectivity-subjectivity dilemmas that Nagel has sharply posed are some= how related to epistemological problems in both mathematical logic, and as we saw earlier, the foundations of physics. These ideas are developed in more detail in the last chapter of Gödel, Escher, Bach by Hofstadter

D.R.H.

Part VI: The Inner Eye

2007-02-14T05:56:00.001-08:00

Chapter 23: An Unfortunate Dualist

2007-02-14T05:54:00.000-08:00

Once upon a time there was a dualist. He believed that mind and matter are separate substances. Just how they interacted he did not pretend to know-this was one of the "mysteries" of life. But he was sure they were quite separate substances.
This dualist, unfortunately, led an unbearably painful life-not because of his philosophical beliefs, but for quite different reasons. And he had excellent empirical evidence that no respite was in sight for the rest of his life. He longed for nothing more than to die. But he was deterred from suicide by such reasons as: (1) he did not want to hurt other people by his death; (2) he was afraid suicide might be morally wrong; (3) he was afraid there might be an afterlife, and he did not want to risk the possibility of eternal punishment. So our poor dualist was quite desperate.
Then came the discovery of the miracle drug! Its effect on the taker was to annihilate the soul or mind entirely but to leave the body functioning exactly as before. Absolutely no observable change came over the taker; the body continued to act just as if it still had a soul. Not the closest friend or observer could possibly know that the taker had taken the drug, unless the taker informed him.
Do you believe that such a drug is impossible in principle? Assuming you believe it possible, would you take it? Would you regard it as immoral? Is it tantamount to suicide? Is there anything in Scriptures forbid

"An Unfortunate Dualist" from This Book Needs No Title by Raymond M. Smullyan. Copyright © 1980 by Raymond M. Smullyan. Published by Prentice-Hall, Inc., Englewood Cliffs, N J.

ding the use of such a drug? Surely, the body of the taker can still fulfill all its responsibilities on earth. Another question: Suppose your spouse took such a drug, and you knew it. You would know that she (or he) no longer had a soul but acted just as if she did have one. Would you love your mate any less?
To return to the story, our dualist was, of course, delighted! Now he could annihilate himself (his soul, that is) in a way not subject to any of the foregoing objections. And so, for the first time in years, he went to bed with a light heart, saying: "Tomorrow morning I will go down to the drugstore and get the drug. My days of suffering are over at last!" With these thoughts, he fell peacefully asleep.
Now at this point a curious thing happened. A friend of the dualist who knew about this drug, and who knew of the sufferings of the dualist, decided to put him out of his misery. So in the middle of the night, while the dualist was fast asleep, the friend quietly stole into the house and injected the drug into his veins. The next morning the body of the dualist awoke-without any soul indeed-and the first thing it did was to go to the drugstore to get the drug. He took it home and, before taking it, said, "Now I shall be released." So he took it and then waited the time interval in which it was supposed to work. At the end of the interval he angrily exclaimed: "Damn it, this stuff hasn't helped at all! I still obviously have a soul and am suffering as much as ever!"
Doesn't all this suggest that perhaps there might be something just a little wrong with dualism?

Raymond M. Smullyan

Reflections

"O Seigneur, s''il y a un Seigneur, sauvez mon âme, si j´ai um âme. "

"0 Lord, if there is a Lord, save my soul, if I have a soul."
--Ernest Renan
Prière d´un sceptique

Smullyan provides a provocative riposte to Searle's thrust-an intentionality-killing potion. The soul of a sufferer is annihilated and yet, to all , external eyes, the suffering goes on unabated. What about to the inner "I"? Smullyan leaves no doubt as to how he feels.

The point of this little fable is the logical absurdity of such a potion. But why is this? Why can't the soul depart and leave behind a soulless, feelingless, yet living and normal-seeming being?
Soul represents the perceptually unbreachable gulf between principles and particles. The levels in between are so many and so murky that we not only see in each person a soul but are unable to unsee it. "Soul" is the name we give to that opaque yet characteristic style of each individual. Put another way, your soul is the "incompressible core" that determines how you are, hence who you are. But is this incompressible core a set of moral principles or personality traits, or is it something that we can speak of in physical terms-in brain language?
The brain's neurons respond only to "local" stimuli-local in both space and time. At each instant (as in the Game of Life, described in the Reflections on "Non Serviam"), the neighboring neurons' influences are added together and the neuron in question either fires or doesn't. Yet somehow all of this "local" behavior can add up to a Grand Style-to a set of "global" principles that, seen on the level of human behavior, embody long-term goals, ideals, interests, tastes, hopes, fears, morals, and so on. So somehow all of these long-term global qualities have to be coded into the neurons in such a way that, from the neurons' firings, the proper global behavior will emerge. We can call this a "flattening" or "compressing" of the global into the local. Such coding of many longterm, high-level goals into the. synaptic structures of billions of neurons has been partially done for us by our millions of ancestors, way back in the evolutionary tree. We owe much not only to those who survived, but also to those who perished, since it is only thanks to the multiple branchings at every stage that evolution could work its miracles to give rise to a creature of such complexity as a person.
Consider a simpler animal, such as a newborn calf. An hour-old calf not only can see and walk, but will instinctively shy away from people. Such behavior comes from ancient sources-namely, the higher survival rate of "protocows" that had genes for this kind of behavior. Such behavior, along with a million other successful adaptations, has been "flattened" into neural patterns coded for in the bovine genes, and is now a ready-made feature of each calf as it comes off the assembly line. Seen on its own, the set of cow genes or human genes seems a miracle-nearly inexplicable. So much history has been flattened into molecular patterns. In order to demystify this, you would have to work backward, reconstruct ing the evolutionary tree-and not just the branches that survived! But we don't see the whole tree of predecessors, successful and otherwise, when we look at an individual cow, and so we can be amazed by the

long-term purposes, goals, and so forth that we see flattened in its brain structure. Our amazement is particularly great when we try to image how, inside its head, millions of individually purposeless local neural firings are adding up to a coherent purposive style-the soul of one c
In humans, by contrast, the mind and character continue to shaped for years after birth, and over this long time span neurons absorb feedback from the environment and self-modify in such a way as to but up a set of styles. The lessons of childhood are flattened into unconscious firing patterns, and when all of these tiny learned neural patterns act in concert with the myriad tiny neural patterns coded for in genes, a human perceiver will see one large pattern emerge-the soul of one human. is why the idea of a potion that "kills the soul" and yet leaves the behavior patterns invariant makes no sense.
Under pressure, of course, a soul-a set of principles-may party fold. What might have seemed "incompressible" may in fact yield t greed, fame, vanity, corruption, fear, torture, or whatever. In this way, "soul" can be broken. Orwell's novel 1984 gives a vivid description of the mechanics of soul breaking. People who are brainwashed by cults o terrorist groups that hold them captive for long periods of time can lose the global coherence of drives so carefully compressed over years into, their neurons. And yet there is a kind of resilience, a tendency to return to some sort of "resting position"-the central soul, the innermost core -even after horrendous, grueling episodes. This could be called "ho meostasis of the spirit."
Let us move to a jollier note. Imagine a soul-free universe, a mechanistic universe with nary a speck of free will or consciousness to be found not a perceiver anywhere. This universe might be deterministic or mi be filled with arbitrary, random, capricious, and causeless events. It i law-governed enough, though, that stable structures can emerge an(( evolve. In this universe, then, are swarming many distinct, tightly knit self-sufficient little objects, each one with an internal representation system of enough complexity as to engender a deep, rich self-image. In each one of them this will give rise to (and here we onlookers must be pardoned for smiling with wry amusement) the illusion of free will-when in fact, of course, this is just a cold universe and these objects that populate, it are just robotlike, rule-bound machines, moving around in deterministic (or capricio-deterministic) trajectories, and kidding themselves that they're exchanging meaningful ideas when in reality they're just mechanically chattering back and forth by emitting and absorbing long trains of empty, hollow, meaningless electromagnetic or perhaps acoustical waves.
Having imagined this strange universe filled with illusions, one can

now take a look out at this universe and see all of humanity in thin disorienting light. One can de-soul-ify everyone in the world, so that they're all like Smullyan's zombie or Searle's Chinese-speaking robo~ seeming to have an inner life but in fact as devoid of soul as is a clacking typewriter driven by a cold, feelingless computer. Life then seems a crud hoax on all those soul-free shells, erroneously "convinced" (although how can a heap of dead atoms be convinced?) that they are conscious:
And this would be the best possible way to look at people, were not for one tiny fact that seems to mess it up: I, the observer, am one of them, yet am undeniably conscious! The rest of them are, for all I know just bundles of empty reflexes that feign consciousness-but not this one After I've died-well, then this vision will be an accurate accounting of the way things are. But until that moment, one of the objects will remai special and different, because it is not being fooled! Or ... might there be something just a little wrong with dualism?
Dualists maintain, as Smullyan puts it, that mind and matter ai separate substances. That is, there are (at least) two kinds of stuff: physic stuff and mental stuff. The stuff our minds are made of has no mass, r physical energy-perhaps not even a location in space. This view is : mysterious, so systematically immune to clarification, that one may well wonder what attracts anyone to it. One broad highway leading to dualism goes through the following (bad) argument:

Some facts are not about the properties, circumstances, and relations of physic objects.
Therefore some facts are about the properties, circumstances, and relations nonphysical objects.

What's wrong with this argument? Try to think of examples of facts that are not about physical objects. The fact that the narrator in Moby Dick called Ishmael is a fact in good standing, but what is it about? One mid want to insist (implausibly) that it is really about certain ink shapes certain bound stacks of printed pages; or one might say (somewhat mysteriously) that it is a fact all right, but it is not about anything at all; waving one's hands a bit, one might say that it is a fact about an abstract object-in much the way the fact that 641 is a prime number is a fact about an abstract object. But almost no one (we suppose) is attracted the view that it is a fact about a perfectly real but nonphysical person named Ishmael. This last view takes novel writing to be a method of ghost manufacture; it takes too literally the familiar hyperbole about an author’s characters coming to life, having wills of their own, rebelling against the creator. It is literary dualism. (Anybody might seriously wonder if Jack the

Ripper was really the Prince of Wales, for they were both real people -- or maybe a single real person. A literary dualist might seriously wonder if Professor Moriarty were really Dr. Watson.) Dualists believe that over, and above the physical things and events there are other, nonphysical things and events that have some sort of independent existence.
When asked to say more, dualists divide into two schools: those who hold that the occurrence or existence of a mental event has no effect whatsoever on subsequent physical events in the brain, and those who deny this and hold that mental events do have effects on physical events in the brain. The former are called epiphenomenalists and the latter are called interactionists. Smullyan's fable nicely disposes of epiphenomenalism (doesn't it?), but what of interactionism?
Ever since Descartes first struggled with it, interactionists have ha the apparently insuperable problem of explaining how an event with no physical properties-no mass, no charge, no location, no velocity-could make a physical difference in the brain (or anywhere else). For a nonphysical event to make a difference, it must make some physical event happen that wouldn't have happened if the nonphysical event hadn't happened. But if we found a sort of event whose occurrence had this sort of effect, why wouldn't we decide for that very reason that we had discovered a new sort of physical event? When antimatter was first postulated, by physicists, dualists didn't react with glee and taunts of "I told you so!"' Why not? Hadn't physicists just supported their claim that the universe had two radically different sorts of stuff in it? The main trouble with antimatter, from the dualists' point of view, was that however exotic it was, it was still amenable to investigation by the methods of the phys, sciences. Mind-stuff, on the other hand, was supposed to be off limit/ science. But if it is, then we have a guarantee that the mystery will never go away. Some people like that idea.

D.R.H.

Chapter 22: Minds, Brains and Programs

2007-02-14T05:52:00.000-08:00

What psychological and philosophical significance should we attach to recent efforts at computer simulations of human cognitive capacities? In answering this question, I find it useful to distinguish what I will call "strong" Al from "weak" or "cautious" Al (artificial intelligence). According to weak Al, the principal value of the computer in the study of the mind is that it gives us a very powerful tool. For example, it enables us to formulate and test hypotheses in a more rigorous and precise fashion. But according to strong AI, the computer is not merely a tool in the study of the mind; rather, the appropriately programmed computer really is a mind, in the sense that computers given the right programs can be literally said to understand and have other cognitive states. In strong AI, because the programmed computer has cognitive states, the pro. grams are not mere tools that enable us to test psychological explanations; rather, the programs are themselves the explanations.
I have no objection to the claims of weak Al, at least as far as thi., article is concerned. My discussion here will be directed at the claims I have defined as those of strong Al, specifically the claim that the appropriately programmed computer literally has cognitive states and that that the

"Minds, Brains, and Programs," by John R. Searle, from The Behavioral and Brain Sciences Vol. 3. Copyright © 1980 Cambridge University Press. Reprinted by permission of Cambridge University Press.

programs thereby explain human cognition. When I hereafter refer, I have in mind the strong version, as expressed by these two claims.
I will consider the work of Roger Schank and his colleagues at (Schank and Abelson 1977), because I am more familiar with it than with any other similar claims, and because it provides a very clear example of the sort of work I wish to examine. But nothing that follows depends upon the details of Schank's programs. The same arguments would apply to Winograd's SHRDLU (Winograd 1973), Weizenba ELIZA (Weizenbaum 1965), and indeed any Turing machine simulation of human mental phenomena. [See "Further Reading" for Searle’s references.]

Very briefly, and leaving out the various details, one can des Schank's program as follows: The aim of the program is to simulate human ability to understand stories. It is characteristic of human being story-understanding capacity that they can answer questions about story even though the information that they give was never explicitly stated in the story. Thus, for example, suppose you are given the following story: "A man went into a restaurant and ordered a hamburger. When the hamburger arrived it was burned to a crisp, and the man stormed of the restaurant angrily, without paying for the hamburger or leaving a tip." Now, if you are asked "Did the man eat the hamburger?" you presumably answer, "No, he did not." Similarly, if you are given following story: "A man went into a restaurant and ordered a hamburger when the hamburger came he was very pleased with it; and as he left restaurant he gave the waitress a large tip before paying his bill," and are asked the question, "Did the man eat the hamburger?" you presumably answer, "Yes, he ate the hamburger." Now Schank's machines can similarly answer questions about restaurants in this fashion To do this, they have a "representation" of the sort of information t human beings have about restaurants, which enables them to answer such questions as those above, given these sorts of stories. When the machine is given the story and then asked the question, the machine will print out answers of the sort that we would expect human beings to give if told similar stories. Partisans of strong Al claim that in this question and answer sequence the machine is not only simulating a human ability but also (1) that the machine can literally be said to understand the story and provide the answers to questions, and (2) that what the machine and its program do explains the human ability to understand the story and answer questions about it.
Both claims seem to me to be totally unsupported by Schank's work as I will attempt to show in what follows. (I am not, of course, saying Schank himself is committed to these claims.)

One way to test any theory of the mind is to ask oneself what it would be like if my mind actually worked on the principles that the theory says all minds work on. Let us apply this test to the Schank program with the following Gedankenexperiment. Suppose that I'm locked in a room and given a large batch of Chinese writing. Suppose furthermore (as is indeed the case) that I know no Chinese, either written or spoken, and that I'm not even confident that I could recognize Chinese writing as Chinese writing distinct from, say, Japanese writing or meaningless squiggles. To me, Chinese writing is just so many meaningless squiggles. Now suppose further that after this first batch of Chinese writing I am given a second batch of Chinese script together with a set of rules for correlating the second batch with the first batch. The rules are in English, and I understand these rules as well as any other native speaker of English. They enable me to correlate one set of formal symbols with another set of formal symbols, and all that "formal" means here is that I can identify the symbols entirely by their shapes. Now suppose also that I am given a third batch of Chinese symbols together with some instructions, again in English, that enable me to correlate elements of this third batch with the first two batches, and these rules instruct me how to give back certain Chinese symbols with certain sorts of shapes in response to certain sorts of shapes given me in the third batch. Unknown to me, the people who are giving me all of these symbols call the first batch a "script," they call the second batch a "story," and they call the third batch "questions." Furthermore, they call the symbols I give them back in response to the third batch "answers to the questions," and the set of rules in English that they gave me, they call the "program." Now just to complicate the story a little, imagine that these people also give me stories in English, which I understand, and they then ask me questions in English about these stories, and I give them back answers in English. Suppose also that after a while I get so good at following the instructions for manipulating the Chinese symbols and the programmers get so good at writing the programs that from the external point of view-that is, from the point of view of somebody outside the room in which I am locked-my answers to the questions are absolutely indistinguishable from those of native Chinese speakers. Nobody just looking at my answers can tell that I don't speak a word of Chinese. Let us also suppose that my answers to the English questions are, as they no doubt would be, indistinguishable from those of other native English speakers, for the simple reason that I am a native English speaker. From the external point of view-from the point of view of someone reading my "answers"-the answers to the Chinese questions and the English questions are equally good. But in the Chinese case, unlike the English case, I produce the answers by manipulating uninter-

preted formal symbols. As far as the Chinese is concerned, I simply behave like a computer: I pet form computational operations on formally specified elements. For the purposes of the Chinese, I am simply an instantiation of the computer program.
Now the claims made by strong Al are that the programmed computer understands the stories and that the program in some sense explains human understanding. But we are now in a position to examine . these claims in light of our thought experiment.
1. As regards the first claim, it seems to me quite obvious in the example that I do not understand a word of the Chinese stories. I have inputs and outputs that are indistinguishable from those of the native Chinese speaker, and I can have any formal program you like, but I still understand nothing. For the same reasons, Schank's computer understands nothing of any stories, whether in Chinese, English, or whatever, since in the Chinese case the computer is me, and in cases where the computer is not me, the computer has nothing more than I have in the case where I understand nothing.
2. As regards the second claim, that the program explains human understanding, we can see that the computer and its program do not provide sufficient conditions of understanding since the computer and the program are functioning, and there is no understanding. But does it even provide a necessary condition or a significant contribution to understanding? One of the claims made by the supporters of strong Al is that when I understand a story in English, what I am doing is exactly the same -or perhaps more of the same-as what I was doing in manipulating the Chinese symbols. It is simply more formal symbol manipulation that distinguishes the case in English, where I do understand, from the case in Chinese, where I don't. I have not demonstrated that this claim is false, but it would certainly appear an incredible claim in the example. Such plausibility as the claim has derives from the supposition that we can construct a program that will have the same inputs and outputs as native speakers, and in addition we assume that speakers have some level of description where they are also instantiations of a program. On the basis of these two assumptions we assume that even if Schank's program isn't the whole story about understanding, it may be part of the story. Well, I suppose that is an empirical possibility, but not the slightest reason has so far been given to believe that it is true, since what is suggested though certainly not demonstrated-by the example is that the computer program is simply irrelevant to my understanding of the story. In the Chinese case I have everything that artificial intelligence can put into me by way of 'a program, and I understand nothing: in the English case I

understand everything, and there is so far no reason at all to suppose that my understanding has anything to do with computer programs, that is, if, computational operations on purely formally specified elements. As long as the program is defined in terms of computational operations on purely formally defined elements, what the example suggests is that these by themselves have no interesting connection with understanding. They are certainly not sufficient conditions, and not the slightest reason has been given to suppose that they are necessary conditions or even that the, make a significant contribution to understanding. Notice that the force of the argument is not simply that different machines can have the same input and output while operating on different formal principles that is not the point at all. Rather, whatever purely formal principles you put into the computer, they will not be sufficient for understanding, since a human will be able to follow the formal principles without understanding anything. No reason whatever has been offered to suppose that such principles are necessary or even contributory, since no reason has been given to suppose that when I understand English I am operating with any formal program at all.
Well. then, what is it that I have in the case of the English sentences that 1 do not have in the case of the Chinese sentences? The obvious answer is that I know what the former mean, while I haven't the faintest idea what the latter mean. But in what does this consist and why couldn't we give it to a machine, whatever it is? I will return to this question later, but first I want to continue with the example.
I have had the occasions to present this example to several workers in artificial intelligence, and, interestingly, they do not seem to agree on 1, hat the proper reply to it is. I get a surprising variety of replies, and in what follows I will consider the most common of these (specified along with their geographic origins).
But first I want to block some common misunderstandings about "understanding": In many of these discussions one finds a lot of fancy footwork about the word "understanding." My critics point out that there are many different degrees of understanding; that "understanding" is not a simple two-place predicate; that there are even different kinds and levels of understanding, and often the law of excluded middle doesn't ev en apply in a straightforward way to statements of the form "x understands that in many cases it is a matter for decision and not a simple matter of fact whether x understands v: and so on. To all of these points t \ -lit to say: of course, of course. But they have nothing to do with the Points at issue. There are clear cases in which "understanding" literally applies and clear cases in which it does not apply; and these two sorts of

cases are all I need for this argument.* I understand stories in E to a lesser degree I can understand stories in English, to a lesser degree I can understand stories in French; to a still lesser degree, stories in German; and in Chinese, not at all. My car and my adding machine, on the other hand, understand nothing: nothing: they are not in that line of business. We often attribute "understanding" and other cognitive predicates by metaphor and analogy to cars, adding machines and other artifacts, but nothing is proved by such attributions. We say “The door knows when to open because of its photoelectric cell.” The adding machine knows how (understands how, is able) to do addition and subtraction but not division," and "The thermostat perceives changes in the temperature.” The reason we make these attributions is quite interesting and it has to do with the fact that in artifacts we extend ours own intentional our tools are extensions of our purposes and so we find it natural to make metaphorical attributions of intentionality to them; but I take it no philosophical ice is cut by such examples The sense in which an automatic door "understands instructions" from its photoelectric cell is not a the sense in which I understand English If the sense in which Schank’s programmed computers understand stories is supposed to be the metaphorical sense in which the door understands and not the sense in which I understand English, the issue would not be worth discussing. But well and Simon (1963) write that the kind of cognition they claim for computers is exactly the same as for human beings. I like the straightforwardness of this claim, and it is the sort of claim I will be considering. I will argue that in the literal sense the programmed computer understands what the car and the adding machine understand, namely, exactly nothing. The computer understanding is not just like my understanding of German) partial or incomplete; it is zero
Now to the replies:

L The Systems Reply (Berkeley) "While it is true that the individual person who is locked in the room does not understand the story, the fact is that he is merely part of a whole system; and the system does understand the story. The person has a large ledger in front of him in which are written the rules, he has a lot of scratch paper and pencils for doing calculations, he has `data banks' of sets of Chinese symbols. Now, understanding is not being ascribed to the mere individual; rather it is being ascribed to this whole system of which he is a part."

*Also, "understanding" implies both the possession of mental (intentional) states and truth (validity, success) of these states. For the purposes of this discussion we arew concerned only with the possession of the states.
Intentionality is by definition that feature of certain mental states by which they are directed at or about objects and states of affairs in the world. Thus, beliefs, desires and intentions are intentional states; undirected forms of anxiety and depression are not.

My response to the systems theory is quite simple: Let the individual internalize all of these elements of the system. He memorizes the rules in the ledger and the data banks of Chinese symbols, and he does all the calculations in his head. The individual then incorporates the entire system. There isn’t anything at all to the system that he does not encompass. We can even get rid of the room and suppose he works outdoors. All the same, he understands nothing of the Chinese, and a fortiori neither does the system, because there isn t anything in the system that isn't in him. If he doesn't understand, then there is no way the system could understand because the system is just a part of him.
Actually I feel somewhat embarrassed to give even this answer to the systems theory because the theory seems to me so implausible to start with. The idea is that while a person doesn't understand Chinese, somehow the conjunction of that person and bits of paper might understand Chinese. It is not easy for me to imagine how someone who was not in the grip of an ideology would find the idea at all plausible. Still, I think many people who are committed to the ideology of strong AI will in the end be inclined to say something very much like this; so let us pursue it a bit further. According to one version of this view, while the man in the internalized systems example doesn't understand Chinese in the sense that a native Chinese speaker does (because, for example, he doesn't know that the story refers to restaurants and hamburgers, etc.), still "the man as a formal symbol manipulation system" really does understand Chinese. The subsystem of the man that is the formal symbol manipulation system for Chinese should not be confused with the subsystem for English.
So there are really two subsystems in the man; one understands English, the other Chinese, and "it's just that the two systems have little to do with each other." But, I want to reply, not only do they have little to do with each other, they are not even remotely alike. The subsystem that understands English (assuming we allow ourselves to talk in this jargon of "subsystems" for a moment) knows that the stories are about restaurants and eating hamburgers, he knows that he is being asked questions about restaurants and that he is answering questions as best he can by making various inferences from the content of the story, and so on. But the Chinese system knows none of this. Whereas the English subsystem knows that "hamburgers" refers to hamburgers, the Chinese subsystem knows only that "squiggle squiggle" is followed by "squoggle squoggle." All he knows is that various formal symbols are being introduced at one end and manipulated according to rules written in English, and other symbols are going out at the other end. The whole point of the original example was to argue that such symbol manipulation by itself couldn't be sufficient for understanding Chinese in any literal sense be-

cause the man could write "squoggle squoggle" after "squiggle gle" without understanding anything in Chinese. And it doesn't me argument to postulate subsystems within the man, because the s terns are no better off than the man was in the first place; they still have anything even remotely like what the English-speaking man subsystem) has. Indeed, in the case as described, the Chinese subsystem is simply a part of the English subsystem, a part that engages in mea less symbol manipulation according to rules in English.
Let us ask ourselves what is supposed to motivate the systems in the first place; that is, what independent grounds are there supposed be for saying that the agent must have a subsystem within him literally understands stories in Chinese? As far as I can tell the o grounds are that in the example I have the same input and output native Chinese speakers and a program that goes from one to the o But the whole point of the examples has been to try to show that that couldn’t be sufficient for understanding, in the sense in which I understand stories in English, because a person, and hence the set of systems that go to make up a person, could have the right combination of input, output, and program and still not understand anything in the relevant literal sense in which I understand English. The only motivation for saying there must be a subsystem in me that understands Chinese is that I have a program and I can pass the Turing test; I can fool native Chi speakers. But precisely one of the points at issue is the adequacy of Turing test. The example shows that there could be two "systems," of which pass the Turing test, but only one of which understands; an is no argument against this point to say that since they both pass Turing test they must both understand, since this claim fails to meet argument that the system in me that understands English has a great d more than the system that merely processes Chinese. In short, the ,s terns reply simply begs the question by insisting without argument the system must understand Chinese.
Furthermore, the systems reply would appear to lead to consequences that are independently absurd. If we are to conclude that the must be cognition in me on the grounds that I have a certain sort of in and output and a program in between, then it looks like all sorts noncognitive subsystems are going to turn out to be cognitive. For ex ple, there is a level of description at which my stomach does information processing, and it instantiates any number of computer programs, but take it we do not want to say that it has any understanding (cf. Pylyshyn 1980). But if we accept the systems reply, then it is hard to see how we avoid saying that stomach, heart, liver, and so on are all understanding subsystems, since there is no principled way to distinguish the motivation

For saying the Chinese subsystem understands from saying that the stomach understands. It is, by the way, not an answer to this point to say that the Chinese system has information as input and output and the stomach has food and food products as input and output, since from the point of view of the agent, from my point of view, there is no information in either the food or the Chinese-the Chinese is just so many meaningless squiggles. The information in the Chinese case is solely in the eyes of the programmers and the interpreters, and there is nothing to prevent them from treating the input and output of my digestive organs as information if they so desire.
This last point bears on some independent problems in strong Al, and it is worth digressing for a moment to explain it. If strong Al is to be a branch of psychology, then it must be able to distinguish those systems that are genuinely mental from those that are not. It must be able to distinguish the principles on which the mind works from those on which nonmental systems work; otherwise it will offer us no explanations of what is specifically mental about the mental. And the mental-nonmental distinction cannot be just in the eye of the beholder but it must be intrinsic to the systems; otherwise it would be up to any beholder to treat people as nonmental and, for example, hurricanes as mental if he likes. But quite often in the AI literature the distinction is blurred in ways that would in the long run prove disastrous to the claim that AI is a cognitive inquiry. McCarthy, for example, writes. "Machines as simple as thermostats can be said to have beliefs, and having beliefs seems to be a characteristic of most machines capable of problem solving performance" (McCarthy 1979). Anyone who thinks strong AI has a chance as a theory of the mind ought to ponder the implications of that remark. We are asked to accept it as a discovery of strong AI that the hunk of metal on the wall that we use to regulate the temperature has beliefs in exactly the same sense that we, our spouses, and our children have beliefs, and furthermore that "most" of the other machines in the room-telephone, tape recorder, adding machine, electric light switch-also have beliefs in this literal sense. It is not the aim of this article to argue against McCarthy's point, so I will simply assert the following without argument The study of the mind starts with such facts as that humans have beliefs while thermostats, telephones, and adding machines don't. If you get theory that denies this point you have produced a counterexample to the theory and the theory is false. One gets the impression that people in Al who write this sort of thing think they can get away with it because the don't really take it seriously, and they don't think anyone else will either I propose, for a moment at least, to take it seriously. Think hard for one Minute about what would be necessary to establish that that hunk of metal

on the wall over there had real beliefs, beliefs with direction of fit, propositional content, and conditions of satisfaction; beliefs that had the possibility of being strong beliefs or weak beliefs; nervous, anxious, or beliefs; dogmatic, rational, or superstitious beliefs; blind faiths or hesitant cogitations; any kind of beliefs. The thermostat is not a candidate. Neither is stomach, liver, adding machine, or telephone. However, since we are taking the idea seriously, notice that its truth would be fatal to strong Al's claim to be a science of the mind. For now the mind is everywhere. What we wanted to know is what distinguishes the mind thermostats and livers. And if McCarthy were right, strong Al would have a hope of telling us that.

2. The Robot Reply (Yale). "Suppose we wrote a different kind program from Schank's program. Suppose we put a computer ins' robot, and this computer would not just take in formal symbols as in and give out formal symbols as output, but rather would actually ope the robot in such a way that the robot does something very much perceiving, walking, moving about, hammering nails, eating, drinking anything you like. The robot would, for example, have a television era attached to it that enabled it to see, it would have arms and legs enabled it to `act,' and all of this would be controlled by its compu `brain.' Such a robot would, unlike Schank's computer, have genus understanding and other mental states."
The first thing to notice about the robot reply is that it tacitly c cedes that cognition is not solely a matter of formal symbol manipulation since this reply adds a set of causal relations with the outside world Fodor 1980). But the answer to the robot reply is that the addition of "perceptual" and "motor" capacities adds nothing by way of understanding, in particular, or intentionality, in general, to Schank's original gram. To see this, notice that the same thought experiment applies to robot case. Suppose that instead of the computer inside the robot, put me inside the room and, as in the original Chinese case, you give more Chinese symbols with more instructions in English for match' Chinese symbols to Chinese symbols and feeding back Chinese symbol to the outside. Suppose, unknown to me, some of the Chinese sym that come to me come from a television camera attached to the robot other Chinese symbols that I am giving out serve to make the mot inside the robot move the robot's legs or arms. It is important to emphasize that all I am doing is manipulating formal symbols: I know none these other facts. I am receiving "information" from the robot's "perceptual" apparatus, and I am giving out "instructions" to its motor apparatus, without knowing either of these facts. I am the robot's homunculus, but

unlike the traditional homunculus, I don't know what's going on. I don't understand anything except the rules for symbol manipulation. Now in this case I want to say that the robot has no intentional states at all; it is Simply moving about as a result of its electrical wiring and its program. And furthermore, by instantiating the program I have no intentional states of the relevant type. All I do is follow formal instructions about manipulating formal symbols.

3. The Brain Simulator Reply (Berkeley and M.I.T.). "Suppose we design a program that doesn't represent information that we have about the world, such as the information in Schank's scripts, but simulates the actual sequence of neuron firings at the synapses of the brain of a native Chinese speaker when he understands stories in Chinese and gives answers to them. The machine takes in Chinese stories and questions about them as input, it simulates the formal structure of actual Chinese brains in processing these stories, and it gives out Chinese answers as outputs. We can even imagine that the machine operates, not with a single serial program, but with a whole set of programs operating in parallel, in the manner that actual human brains presumably operate when they process natural language. Now surely in such a case we would have to say that the machine understood the stories; and if we refuse to say that, wouldn't we also have to deny that native Chinese speakers understood the stories? At the level of the synapses, what would or could be different about the program of the computer and the program of the Chinese brain?"
Before countering this reply I want to digress to note that it is an odd reply for any partisan of artificial intelligence (or functionalism, etc.) to make: I thought the whole idea of strong AI is that we don't need to know how the brain works to know how the mind works. The basic hypothesis, or so I had supposed, was that there is a level of mental operations consisting of computational processes over formal elements that constitute the essence of the mental and can be realized in all sorts of different brain processes, in the same way that any computer program can be realized in different computer hardwares: On the assumptions of strong Al, the mind is to the brain as the program is to the hardware, and thus we can understand the mind without doing neurophysiology. If we had to know how the brain worked to do AI, we wouldn't bother with AI. However, even getting this close to the operation of the brain is still not sufficient to produce understanding. To see this, imagine that instead of a monolingual man in a room shuffling symbols we have the man operate an elaborate set of water pipes with valves connecting them. When the man receives the Chinese symbols, he looks up in the program, written In English, which valves he has to turn on and off. Each water connection

corresponds to a synapse in the Chinese brain, and the whole system is rigged up so that after doing all the right firings, that is after turning on all the right faucets, the Chinese answers pop out at the output end out of the series of pipes.
Now where is the understanding in this system? It takes Chinese as input, it simulates the formal structure of the synapses of the Chin brain, and it gives Chinese as output. But the man certainly does understand Chinese, and neither do the water pipes, and if we tempted to adopt what I think is the absurd view that somehow t conjunction of man and water pipes understands, remember that in principle the man can internalize the formal structure of the water pipes do all the "neuron firings" in his imagination. The problem with the b simulator is that it is simulating the wrong things about the brain. As lo as it simulates only the formal structure of the sequence of neuron fin at the synapses, it won't have simulated what matters about the bra namely its causal properties, its ability to produce intentional states. A that the formal properties are not sufficient for the causal properties shown by the water pipe example: we can have all the formal property carved off from the relevant neurobiological causal properties.

4. The Combination Reply (Berkeley and Stanford). "While each the previous three replies might not be completely convincing by it as a refutation of the Chinese room counterexample, if you take all th together they are collectively much more convincing and even decisive Imagine a robot with a brain-shaped computer lodged in its cranial cavity imagine the computer programmed with all the synapses of a hum brain, imagine the whole behavior of the robot is indistinguishable fro human behavior, and now think of the whole thing as a unified system a not just as a computer with inputs and outputs. Surely in such a case would have to ascribe intentionality to the system."
I entirely agree that in such a case we would find it rational a indeed irresistible to accept the hypothesis that the robot had intentionality, as long as we knew nothing more about it. Indeed, besides appearance and behavior, the other elements of the combination are really irrelevant. If we could build a robot whose behavior was indistinguishable over large range from human behavior, we would attribute intentionality to t pending some reason not to. We wouldn't need to know in advance th its computer brain was a formal analogue of the human brain.
But I really don't see that this is any help to the claims of strong and here's why: According to strong Al, instantiating a formal pro with the right input and output is a sufficient condition of, indeed constitutive of, intentionality. As Newell (1979) puts it, the essence of

mental is the operation of a physical symbol system. But the attributions of intentionality that we make to the robot in this example have nothing to do with formal programs. They are simply based on the assumption that if the robot looks and behaves sufficiently like us, then we would suppose, until proven otherwise, that it must have mental states like ours that cause and are expressed by its behavior and it must have an inner mechanism capable of producing such mental states. If we knew independently how to account for its behavior without such assumptions we would not attribute intentionality to it, especially if we knew it had a formal program. And this is precisely the point of my earlier reply to objection II.
Suppose we knew that the robot's behavior was entirely accounted for by the fact that a man inside it was receiving uninterpreted formal symbols from the robot's sensory receptors and sending out uninterpreted formal symbols to its motor mechanisms, and the man was doing this symbol manipulation in accordance with a bunch of rules. Furthermore, suppose the man knows none of these facts about the robot, all he knows is which operations to perform on which meaningless symbols. In such a case we would regard the robot as an ingenious mechanical dummy. The hypothesis that the dummy has a mind would now be unwarranted and unnecessary, for there is now no longer any reason to ascribe intentionality to the robot or to the system of which it is a part (except of course for the man's intentionality in manipulating the symbols). The formal symbol manipulations go on, the input and output are correctly matched, but the only real locus of intentionality is the man, and he doesn't know any of the relevant intentional states; he doesn't, for example, see what comes into the robot's eyes, he doesn't intend to move the robot's arm, and he doesn't understand any of the remarks made to or by the robot. Nor, for the reasons stated earlier, does the system of which man and robot are a part.
To see this point, contrast this case with cases in which we find it completely natural to ascribe intentionality to members of certain other primate species such as apes and monkeys and to domestic animals such as dogs. The reasons we find it natural are, roughly, two: We can't make sense of the animal's behavior without the ascription of intentionality, and we can see that the beasts are made of similar stuff to ourselves-that is an eye, that a nose, this is its skin, and so on. Given the coherence of the animal's behavior and the assumption of the same causal stuff underlying it, we assume both that the animal must have mental states underlying its behavior, and that the mental states must be produced by mechanisms made out of the stuff that is like our stuff. We would certainly make similar assumptions about the robot unless we had some reason not to,

but as soon as we knew that the behavior was the result of a formal program, and that the actual causal properties of the physical subs were irrelevant we would abandon the assumption of intentionality
There are two other responses to my example that come up frequently (and so are worth discussing) but really miss the point.

5. The Other Minds Reply (Yale). "How do you know that other people understand Chinese or anything else? Only by their behavior. Now computer can pass the behavioral tests as well as they can (in principle so if you are going to attribute cognition to other people you must principle also attribute it to computers."
This objection really is only worth a short reply. The problem in discussion is not about how I know that other people have cognitive states, but rather what it is that I am attributing to them when I attrib cognitive states to them. The thrust of the argument is that it couldn't just computational processes and their output because the computational processes and their output can exist without the cognitive state. It is answer to this argument to feign anesthesia. In "cognitive sciences" o presupposes the reality and knowability of the mental in the same w that in physical sciences one has to presuppose the reality and knowability of physical objects.

6. The Many Mansions Reply (Berkeley). "Your whole argument p supposes that Al is only about analog and digital computers. But that just happens to be the present state of technology. Whatever these causal processes are that you say are essential for intentionality (assuming y are right), eventually we will be able to build devices that have these causal processes, and that will be artificial intelligence. So your arguments are in no way directed at the ability of artificial intelligence produce and explain cognition."
I really have no objection to this reply save to say that it in effect trivializes the project of strong Al by redefining it as whatever artificial produces and explains cognition. The interest of the original claim ma on behalf of artificial intelligence is that it was a precise, well defined thesis: mental processes are computational processes over forma defined elements. I have been concerned to challenge that thesis. If claim is redefined so that it is no longer that thesis, my objections longer apply because there is no longer a testable hypothesis for them to apply to.
Let us now return to the question I promised I would try to answer Granted that in my original example I understand the English and I not understand the Chinese, and granted therefore that the machine

doesn't understand either English or Chinese, still there must be something about me that makes it the case that I understand English and a corresponding something lacking in me that makes it the case that I fail to understand Chinese. Now why couldn't we give those somethings, whatever they are, to a machine?
I see no reason in principle why we couldn't give a machine the capacity to understand English or Chinese, since in an important sense our bodies with our brains are precisely such machines. But I do see very strong arguments for saying that we could not give such a thing to a machine where the operation of the machine is defined solely in terms of computational processes over formally defined elements; that is, where the operation of the machine is defined as an instantiation of a computer program. It is not because I am the instantiation of a computer program that I am able to understand English and have other forms of intentionality (I am, I suppose, the instantiation of any number of computer programs), but as far as we know it is because I am a certain sort of organism with a certain biological (i.e., chemical and physical) structure, and this structure, under certain conditions, is causally capable of producing perception, action, understanding, learning, and other intentional phenomena. And part of the point of the present argument is that only something that had those causal powers could have that intentionality. Perhaps other physical and chemical processes could produce exactly these effects; perhaps, for example, Martians also have intentionality but their brains are made of different stuff. That is an empirical question, rather like the question whether photosynthesis can be done by something with a chemistry different from that of chlorophyll.
But the main point of the present argument is that no purely formal model will ever be sufficient by itself for intentionality because the formal properties are not by themselves constitutive of intentionality, and they have by themselves no causal powers except the power, when instantiated, to produce the next stage of the formalism when the machine is running. And any other causal properties that particular realizations of the formal model have, are irrelevant to the formal model because we can always put the same formal model in a different realization where those causal properties are obviously absent. Even if, by some miracle, Chinese speakers exactly realize Schank's program, we can put the same program in English speakers, water pipes, or computers, none of which understand Chinese, the program notwithstanding.
What matters about brain operations is not the formal shadow cast by the sequence of synapses but rather the actual properties of the sequences. All the arguments for the strong version of artificial intelligence that I have seen insist on drawing an outline around the shadows cast

by cognition and then claiming that the shadows are the real thing.

By way of concluding I want to try to state some of the general philosophical points implicit in the argument For clarity I will try to do it in a question-and-answer fashion, and I begin with that old chestnut a question:
"Could a machine think?"
The answer is, obviously, yes. We are precisely such machines "Yes, but could an artifact a man-made machine, think?" Assuming it is possible to produce artificially a machine with a nervous system, neurons with axons and dendrites, and all the rest of it, sufficiently like ours again the answer to the question seems to be obviously, yes. If you can exactly duplicate the causes, you could duplicate effects. And indeed it might be possible to produce consciousness, intentionality, and all the rest of it using some other sorts of chemical principles than those that human beings use. It is, as I said, an empire question.
"OK, but could a digital computer think?"
If by "digital computer" we mean anything at all that has a level of decryption where it can correctly be described as the instantiation of a computer program, then again the answer is, of course, yes, since we are the instantiations of any number of computer programs and we can think.
"But could something think, understand, and so on solely in virtue of being a computer with the right sort o program? Could instantiating a program, the right program of course, by itself be a sufficient condition of understanding?"
This I think is the right question to ask though it is usually confused with one or more of the earlier questions, and the answer to it is no
"Why not
Because the formal symbol manipulations by themselves don't ha any intentionality; they are quite meaningless; they aren't even symbol manipulations, since the symbols don't symbolize anything. In the linguistic jargon, they have only a syntax but no semantics. Such intentionality as computers appear to have is solely in the minds of those w program tem and those who use them, those who send in the input a those who interpret the output
.
The aim of the Chinese room example was to try to show this showing that as soon as we put something into the system that really does have intentionality (a man), and we program him with the formal program, you can see that the formal program carries no additional intentionality . It adds nothing for example to a mans ability to understand Chinese.

Precisely that feature of Al that seemed so appealing-the distinction between the program and the realization-proves fatal to the claim that simulation could be duplication. The distinction between the program and its realization in the hardware seems to be parallel to the distinction between the level of mental operations and the level of brain operations. And if we could describe the level of mental operations as a formal program, then it seems we could describe what was essential about the mind without doing either introspective psychology or neurophysiology of the brain. But the equation "mind is to brain as program is to hardware" breaks down at several points, among them the following three:
First, the distinction between program and realization has the consequence that the same program could have all sorts of crazy realizations that had no form of intentionality. Weizenbaum (1976, Ch. 2), for example, shows in detail how to construct a computer using a roll of toilet paper and a pile of small stones. Similarly, the Chinese story understanding program can be programmed into a sequence of water pipes, a set of wind machines, or a monolingual English speaker, none of which thereby acquires an understanding of Chinese. Stones, toilet paper, wind, and water pipes are the wrong kind of stuff to have intentionality in the first place-only something that has the same causal powers as brains can have intentionality-and though the English speaker has the right kind of stuff for intentionality you can easily see that he doesn't get any extra intentionality by memorizing the program, since memorizing it won't teach him Chinese.
Second, the program is purely formal, but the intentional states are not in that way formal. They are defined in terms of their content, not their form. The belief that it is raining, for example, is not defined as a certain formal shape, but as a certain mental content with conditions of satisfaction, a direction of fit (see Searle 1979), and the like. Indeed the belief as such hasn't even got a formal shape in this syntactic sense, since one and the same belief can be given an indefinite number of different syntactic expressions in different linguistic systems.
Third, as I mentioned before, mental states and events are literally a product of the operation of the brain, but the program is not in that way a product of the computer.
"Well if programs are in no way constitutive of mental processes, why have so many people believed the converse? That at least needs some explanation."
I don't really know the answer to that one. The idea that computer simulations could be the real thing ought to have seemed suspicious in the first place because the computer isn't confined to simulating mental

operations, by any means. No one supposes that computer simulations of a five-alarm fire will burn the neighborhood down or that a comp simulation of a rainstorm will leave us all drenched. Why on earth w anyone suppose that a computer simulation of understanding act understood anything? It is sometimes said that it would be frightfully hard to get computers to feel pain or fall in love, but love and are neither harder nor easier than cognition or anything else. For stimulation, all you need is the right input and output and a program the middle that transforms the former into the latter. That is all computer has for anything it does. To confuse simulation with duplication is the same mistake, whether it is pain, love, cognition, fires rainstorms.
Still, there are several reasons why AI must have seemed-an many people perhaps still does seem-in some way to reproduce thereby explain mental phenomena, and I believe we will not succeed removing these illusions until we have fully exposed the reasons that rise to them.
First, and perhaps most important, is a confusion about the no of "information processing": many people in cognitive science be that the human brain, with its mind, does something called "inform processing," and analogously the computer with its program does information processing; but fires and rainstorms, on the other hand, don't information processing at all. Thus, though the computer can simulate the formal features of any process whatever, it stands in a special relation to the mind and brain because when the computer is properly programmed, ideally with the same program as the brain, the information processing is identical in the two cases, and this information process is really the essence of the mental. But the trouble with this argument that it rests on an ambiguity in the notion of "information." In the se in which people "process information" when they reflect, say, on problems in arithmetic or when they read and answer questions about sto the programmed computer does not do "information processing Rather, what it does is manipulate formal symbols. The fact that programmer and the interpreter of the computer output use the sym to stand for objects in the world is totally beyond the scope of computer. The computer, to repeat, has a syntax but no semantics. Tb if you type into the computer "2 plus 2 equals?" it will type out "4." it has no idea that "4" means 4 or that it means anything at all. And point is not that it lacks some second-order information about the interpretation of its first-order symbols, but rather that its first-order sym don't have any interpretations as far as the computer is concerned. the computer has is more symbols. The introduction of the notion

information processing" therefore produces a dilemma: either we construe the notion of "information processing" in such a way that it implies intentionality as part of the process or we don't. If the former, then the programmed computer does not do information processing, it only manipulates formal symbols. If the latter, then, though the computer does information processing, it is only doing so in the sense in which adding machines, typewriters, stomachs, thermostats, rainstorms, and hurricanes do information processing; namely, they have a level of description at which we can describe them as taking information in at one end, transforming it, and producing information as output. But in this case it is up to outside observers to interpret the input and output as information in the ordinary sense. And no similarity is established between the computer and the brain in terms of any similarity of information processing.
Second, in much of AI there is a residual behaviorism or operationalism. Since appropriately programmed computers can have input-output patterns similar to those of human beings, we are tempted to postulate mental states in the computer similar to human mental states. But once we see that it is both conceptually and empirically possible for a system to have human capacities in some realm without having any intentionality at all, we should be able to overcome this impulse. My desk adding machine has calculating capacities, but no intentionality, and in this paper I have tried to show that a system could have input and output capabilities that duplicated those of a native Chinese speaker and still not understand Chinese, regardless of how it was programmed. The Turing test is typical of the tradition in being unashamedly behavioristic and operationalistic, and I believe that if Al workers totally repudiated behaviorism and operationalism much of the confusion between simulation and duplication would be eliminated.
Third, this residual operationalism is joined to a residual form of dualism; indeed strong Al only makes sense given the dualistic assumption that, where the mind is concerned, the brain doesn't matter. In strong Al (and in functionalism, as well) what matters are programs, and programs are independent of their realization in machines; indeed, as far as AI is concerned, the same program could be realized by an electronic machine, a Cartesian mental substance, or a Hegelian world spirit. The single most surprising discovery that I have made in discussing these issues is that many AI workers are quite shocked by my idea that actual human mental phenomena might be dependent on actual physical-chemical properties of actual human brains. But if you think about it a minute You can see that I should not have been surprised; for unless you accept some form of dualism, the strong Al project hasn't got a chance. The

project is to reproduce and explain the mental by designing programs but unless the mind is not only conceptually but empirically independent of the brain you couldn't carry out the project, for the program is completely independent of any realization. Unless you believe that the nit is separable from the brain both conceptually and empirically-dualism in a strong form-you cannot hope to reproduce the mental by writing and running programs since programs must be independent of brains any other particular forms of instantiation. If mental operations cons in computational operations on formal symbols, then it follows that they have no interesting connection with the brain; the only connection would be that the brain just happens to be one of the indefinitely many types of machines capable of instantiating the program. This form of dualism is not the traditional Cartesian variety that claims there are two sorts substances, but it is Cartesian in the sense that it insists that what is specifically mental about the mind has no intrinsic connection with the act properties of the brain. This underlying dualism is masked from us by the fact that AI literature contains frequent fulminations against "dualism what the authors seem to be unaware of is that their position presuppose a strong version of dualism.
"Could a machine think?" My own view is that only a machine could think, and indeed only very special kinds of machines, namely brains a machines that had the same causal powers as brains. And that is the main reason strong Al has had little to tell us about thinking, since it h nothing to tell us about machines. By its own definition, it is about programs, and programs are not machines. Whatever else intentionality is, it is a biological phenomenon, and it is as likely to be as causally dependent on the specific biochemistry of its origins as lactation, photosynthesis, or any other biological phenomena. No one would suppose that we could produce milk and sugar by running a computer simulation of the formal sequences in lactation and photosynthesis, but where the mind is concerned many people are willing to believe in such a miracle because of a deep and abiding dualism: the mind they suppose is a matte of formal processes and is independent of quite specific material causes in the way that milk and sugar are not.
In defense of this dualism the hope is often expressed that the brain is a digital computer (early computers, by the way, were often call "electronic brains"). But that is no help. Of course the brain is a dig, computer. Since everything is a digital computer, brains are too. The point is that the brain's causal capacity to produce intentionality cannot consist in its instantiating a computer program, since for any program you like it is possible for something to instantiate that program and still

not have any mental states. Whatever it is that the brain does to produce intentionality, it cannot consist in instantiating a program since no program, by itself, is sufficient for intentionality.

John R. Searle

Reflections

This article originally appeared together with twenty-eight responses from assorted people. Many of the responses contained excellent commentary, but reprinting them would have overloaded this book, and in any case some were a little too technical. One of the nice things about Searle's article is that it is pretty much understandable by someone without special training in Al, neurology, philosophy, or other disciplines that have a bearing on it.
Our position is quite opposed to Searle's, but we find in Searle an eloquent opponent. Rather than attempt to give a thorough rebuttal to his points, we will concentrate on a few of the issues he raises, leaving our answers to his other points implicit, in the rest of this book.
Searle's paper is based on his ingenious "Chinese room thought experiment," in which the reader is urged to identify with a human being executing by hand the sequence of steps that a very clever AI program would allegedly go through as it read stories in Chinese and answered questions about them in Chinese in a manner sufficiently human-seeming as to be able to pass the Turing test. We think Searle has committed a serious and fundamental misrepresentation by giving the impression that it makes any sense to think that a human being could do this. By buying this image, the reader is unwittingly sucked into an impossibly unrealistic concept of the relation between intelligence and symbol manipulation.
The illusion that Searle hopes to induce in readers (naturally he doesn't think of it as an illusion!) depends on his managing to make readers overlook a tremendous difference in complexity between two systems at different conceptual levels. Once he has done that, the rest is a piece of cake. At the outset, the reader is invited to identify with Searle

'I am indebted to a rather large number of people for discussion of these matters and for their patient attempts to overcome my ignorance of artificial intelligence. I would especially like to thank Ned Block, Hubert Dreyfus, John Haugeland, Roger Schank, Robert Wilensky, and Terry Winograd.

as he hand-simulates an existing AI program that can, in a limited w answer questions of a limited sort, in a few limited domains. Now, for person to hand-simulate this, or any currently existing AI program-that is, to step through it at the level of detail that the computer does-would involve days, if not weeks or months, of arduous, horrendous boredom But instead of pointing this out, Searle-as deft at distracting the reader' attention as a practiced magician-switches the reader's image to a hypothetical program that passes the Turing test! He has jumped up man levels of competency without so much as a passing mention. The reader is again invited to put himself or herself in the shoes of the person carrying out the step-by-step simulation, and to "feel the lack of under, standing" of Chinese. This is the crux of Searle's argument.
Our response to this (and, as we shall show later, Searle's response as well, in a way) is basically the "Systems Reply": -that it is a mistake to try to impute the understanding to the (incidentally) animate simulator; rather it belongs to the system as a whole, which includes what Searle casually characterizes as "bits of paper." This offhand comment,, w feel, reveals how Searle's image has blinded him to the realities of t situation. A thinking computer is as repugnant to John Searle as no Euclidean geometry was to its unwitting discoverer, Gerolamo Saccher who thoroughly disowned his own creation. The time-the late 1700s was not quite ripe for people to accept the conceptual expansion caused by alternate geometries. About fifty years later, however, non-Euclidea geometry was rediscovered and slowly accepted.
Perhaps the same will happen with "artificial intentionality"-if it ever created. If there ever came to be a program that could pass th Turing test, it seems that Searle, instead of marveling at the power an depth of that program, would just keep on insisting that it lacked sour marvelous "causal powers of the brain" (whatever they are). To point o the vacuity of that notion, Zenon Pylyshyn, in his reply to Searle, won dered if the following passage, quite reminiscent of Zuboff's "Story of Brain" (selection 12), would accurately characterize Searle's viewpoint

If more and more of the cells in your brain were to be replaced by integrated circuit chips, programmed in such a way as to keep the input-output function each unit identical to that of the unit being replaced, you would in all likelihood just keep right on speaking exactly as you are doing now except that you would eventually stop meaning anything by it. What we outside observers might take t be words would become for you just certain noises that circuits caused you t make.

The weakness of Searle's position is that he offers no clear way to to when genuine meaning-or indeed the genuine "you"-has vanished

from this system. He merely insists that some systems have intentionality by virtue of their "causal powers" and that some don't. He vacillates about what those powers are due to. Sometimes it seems that the brain is composed of "the right stuff," but other times it seems to be something else. It is whatever seems convenient at the moment-now it is the slippery essence that distinguishes "form" from "content," now another essence that separates syntax from semantics, and so on.
To the Systems-Reply advocates, Searle offers the thought that the human being in the room (whom we shall from now on refer to as "Searle's demon") should simply memorize, or incorporate all the material on the "bits of paper." As if a human being could, by any conceivable stretch of the imagination, do this. The program on those "bits of paper" embodies the entire mind and character of something as complex in its ability to respond to written material as a human being is, by virtue of being able to pass the Turing test. Could any human being simply "swallow up" the entire description of another human being's mind? We find it hard enough to memorize a written paragraph; but Searle envisions the demon as having absorbed what in all likelihood would amount to millions, if not billions, of pages densely covered with abstract symbols-and moreover having all of this information available, whenever needed, with no retrieval problems. This unlikely aspect of the scenario is all lightly described, and it is not part of Searle's key argument to convince the reader that it makes sense. In fact, quite the contrary a key part of his argument is in glossing over these questions of orders of magnitude, for otherwise a skeptical reader will realize that nearly all of the understanding must lie in the billions of symbols on paper, and practically none of it in the demon. The fact that the demon is animate is an irrelevant-indeed, misleading-side issue that Searle has mistaken for a very significant fact.
We can back up this argument by exhibiting Searle's own espousal of the Systems Reply. To do so, we should first like to place Searle's thought experiment in a broader context. In particular, we would like to show how Searle's setup is just one of a large family of related thought experiments, several of which are the topics of other selections in this book. Each member of this family of thought experiments is defined by a particular choice of "knob settings" on a thought-experiment generator. Its purpose is to create-in your mind's eye-various sorts of imaginary simulations of human mental activity. Each different thought experiment is an "intuition pump" (Dennett's term) that magnifies one facet or other of the issue, tending to push the reader toward certain conclusions. We see approximately five knobs of interest, although it is possible that someone else could come up with more.

Knob 1. This knob controls the physical "stuff" out of which the simulation be constructed. Its settings include: neurons and chemicals; wat pipes and water; bits of paper and symbols on them; toilet paper a stones; data structures and procedures; and so on.

Knob 2. This knob controls the level of accuracy with which the simulation attempts to mimic the human brain. It can be set at an arbitrarily fi level of detail (particles inside atoms), at a coarser level such as tha of cells and synapses, or even at the level that AI researchers an cognitive psychologists deal with: that of concepts and ideas, representations and processes.

Knob 3. This knob controls the physical size of the simulation. Our assumption is that microminiaturization would allow us to make a teeny-weeny network of water pipes or solid-state chips that would fit inside a thimble, and conversely that any chemical process could be blown up to the macroscopic scale.

Knob 4. This critical knob controls the size and nature of the demon wh carries out the simulation. If it is a normal-sized human being, we shall call it a "Searle's demon." If it is a tiny elflike creature that can sit inside neurons or on particles, then we shall call it a "Haugeland's demon," after John Haugeland, whose response to Searle featured this notion, The settings of this knob also determine whether the demon is animate or inanimate.

Knob 5. This knob controls the speed at which the demon works. It can be set to make the demon work blindingly fast (millions of operations p microsecond) or agonizingly slowly (maybe one operation every few seconds).

Now, by playing with various knob settings, we can come up wi various thought experiments. One choice yields the situation described in selection 26, "A Conversation with Einstein's Brain." Another choice yields Searle's Chinese room experiment. In particular, that involves the following knob settings:

Knob 1: paper and symbols Knob 2: concepts and ideas
Knob 3: room size
Knob 4: human-sized demon
Knob 5: slow setting (one operation every few seconds)
Note that in principle Searle is not opposed to assuming that a simulation with these parameters could pass the Turing test. His dispute is only with what that would imply.
There is one final parameter that is not a knob but a point of view

from which to look at the experiment. Let us add a little color to this drab experiment and say that the simulated Chinese speaker involved is a woman and that the demons (if animate) are always male. Now we have a choice between the demon's-eye view and the system's-eye view. Remember that by hypothesis, both the demon and the simulated woman are equally capable of articulating their views on whether or not they are understanding, and on what they are experiencing. Searle is insistent, nonetheless, that we see this experiment only from the point of view of the demon. He insists that no matter what the simulated woman claims (in Chinese, of course) about her understanding, we should disregard her claims, and pay attention to the demon inside, who is carrying out the symbol manipulation. Searle's claim amounts to the notion that actually there is only one point of view, not two. If one accepts the way Searle describes the whole experiment, this claim has great intuitive appeal, since the demon is about our size, speaks our language, and works at about our speed-and it is very hard to identify with a "woman" whose answers come at the rate of one per century (with luck)-and in "meaningless squiggles and squoggles," to boot.
But if we change some of the knob settings, we can also alter the ease with which we change point of view. In particular, Haugeland's variation involves switching various knobs as follows:

Knob 1: neurons and chemicals Knob 2: neural-firing level
Knob 3: brain size
Knob 4: eensy-weensy demon
Knob 5: dazzlingly fast demon
What Haugeland wants us to envision is this: A real woman's brain is, unfortunately, defective. It no longer is able to send neurotransmitters from one neuron to another. Luckily, however, this brain is inhabited by an incredibly tiny and incredibly speedy Haugeland's demon, who intervenes every single time any neuron would have been about to release neurotransmitters into a neighboring neuron. This demon "tickles" the appropriate synapse of the next neuron in a way that is functionally indistinguishable, to that neuron, from the arrival of genuine neurotransmitters. And the H-demon is so swift that he can jump around from synapse to synapse in trillionths of a second, never falling behind schedule. In this way the operation of the woman's brain proceeds exactly as it would have, if she were healthy. Now, Haugeland asks Searle, does the woman still think-that is, does she possess intentionality-or, to recall the words of Professor Jefferson as cited by Turing, does she merely "artificially signal"?

You might expect Searle to urge us to listen to and identify with demon, and to eschew the Systems Reply, which would be, of course, t listen to and identify with the woman. But in his response to Haugeland„ , Searle surprises us-he chooses to listen to her this time and to ignore the demon who is cursing us from his tiny vantage point, yelling up to us, "Fools! Don't listen to her! She's merely a puppet whose every action is caused by my tickling, and by the program embedded in these many neurons that I zip around among." But Searle does not heed the H. demon's warning cries. He says, "Her neurons still have the right causal powers; they just need some help from the demon."
We can construct a mapping between Searle's original setup and this modified setup. To the "bits of paper" now correspond all the synapses in the woman's brain. To the AI program written on these "bits of paper" corresponds the entire configuration of the woman's brain; this amounts to a gigantic prescription telling the demon when and how to know which synapses to tickle. To the act of writing "meaningless squiggles and squoggles of Chinese" on paper corresponds the act, o tickling her synapses. Suppose we take the setup as is, except that we'll vary the size and speed knobs. We'll blow the woman's brain up to the size of the Earth, so that the demon becomes an "us-sized" S-demon, instead of a tiny H-demon. And let's also have the S-demon act at speed reasonable for humans, instead of zipping thousands of miles throughout this bulbous brain in mere microseconds. Now which level does Searle wish us to identify with? We won't speculate, but it seems to us that if the Systems Reply was compelling in the previous case, it should still be so, in this case.
It must be admitted that Searle's thought experiment vividly raises. the question of what understanding a language really is. We would like: to digress for a moment on that topic. Consider the question: "What kind of ability to manipulate the written or spoken symbols of a language amounts to a true understanding of that language?" Parrots who parro English do not understand English. The recorded voice of a woman announcing the exact time of day on the telephone time service is not th mouthpiece of a system that understands English. There is no mentality behind that voice-it has been skimmed off of its mental substrate, yet retains a human-seeming quality. Perhaps a child would wonder. how anyone could have so boring a job, and could do it so reliably. This would amuse us. It would be another matter, of course, if her voice were being driven by a flexible AI program that could pass the Turing test!
Imagine you are teaching a class in China. Further, imagine that you are aware of formulating all your thoughts in English and then of applying last-minute transformation rules (in reality, they would be last-split-.

second rules) that convert the English thoughts into instructions for moving your mouth and vocal cords in strange, "meaningless" ways -- and yet, all your pupils sit there and seem quite satisfied with your performance. When they raise their hands, they utter exotic sounds that, although they are completely meaningless to you, you are equipped to deal with, as you quickly apply some inverse rules and recover the English meanings underlying them.... Would you feel you were actually speaking Chinese? Would you feel you had gained some insight into the Chinese mentality? Or-can you actually imagine this situation? Is it realistic? Could anyone actually speak a foreign language well using this method?
The standard line is "You must learn to think in Chinese. " But in what does this consist? Anyone who has experienced it will recognize this description: The sounds of the second language pretty soon become "unheard"-you hear right through them, rather than hearing them, as you see right through a window, rather than seeing the window. Of course, you can make yourself hear a familiar language as pure uninterpreted sound if you try very hard, just as you can look at a windowpane if you want; but you can't have your cake and eat it too-you can't hear the sounds both with and without their meanings. And so most of the time people hear mainly meaning. For those people who learn a language because of enchantment with its sounds, this is a bit disappointing-and yet mastery of those sounds, even if one no longer hears them naively, is a beautiful, exhilarating experience. (It would be an interesting thing to try to apply this same kind of analysis to the hearing of music, where the distinction between hearing bare sounds and hearing their "meanings" is far less well understood, yet seems very real.)
Learning a second language involves transcending one's own native language. It involves mixing the new language right in with the medium in which thought takes place. Thoughts must be able to germinate as easily (or nearly as easily) in the new language as in one's native language. The way in which a new language's habits seep down level by level and finally get absorbed into neurons is a giant mystery still. But one thing for certain is that mastery of a language does not consist in getting your "English subsystem" to execute for you a program of rules that enable you to deal with a language as a set of meaningless sounds and marks. Somehow, the new language must fuse with your internal representational system-your repertoire of concepts, images, and so on-in the same intimate way as English is fused with it. To think precisely about this, one must develop a very clear notion of the concept of levels of implementation, a computer-science concept of great power.
Computer scientists are used to the idea that one system can "emu-

late" another system. In fact, it follows from a theorem proven in 1 by Alan Turing that any general-purpose digital computer can take on guise of any other general-purpose digital computer, and the only difference to the outside world will be one of speed. The verb "emulate reserved for simulations, by a computer, of another computer, while "simulate" refers to the modeling of other phenomena, such as hurricanes, population curves, national elections, or even computer users.
A major difference is that simulation is almost always approximate, depending on the nature of the model of the phenomenon in question whereas emulation is in a deep sense exact. So exact is it that when, say a Sigma-5 computer emulates a computer with different architecture say a DEC PDP-10-the users of the machine will be unaware that they - are not dealing with a genuine DEC. This embedding of one architecture in another gives rise to so-called "virtual machines"-in this case, virtual DEC-10. Underneath every virtual machine there is always some; other machine. It may be a machine of the same type, it may even be another virtual machine. In his book Structured Computer Organization, Andrew Tanenbaum uses this notion of virtual machines to explain ho large computer systems can be seen as a stack of virtual machines implemented one on top of the other-the bottommost one being, of course a real machine! But in any case, the levels are sealed off from each other in a watertight way, just as Searle's demon was prevented from talking to the Chinese speaker he was part of. (It is intriguing to imagine what ki of conversation would take place-assuming that there were an interpreter present, since Searle's demon knows no Chinese!)
Now in theory, it is possible to have any two such levels communicate with each other, but this has traditionally been considered bad style level-mingling is forbidden. Nonetheless, it is probable that this forbid den fruit-this blurring of two implementational levels-is exactly what goes on when a human "system" learns a second language. The second language does not run on top of the first one as a kind of software parasite, but rather becomes equally fundamentally implanted in ,.she hardware (or nearly so). Somehow, absorption of a second language, involves bringing about deep changes in one's underlying "machine" a vast and coherent set of changes in the ways that neurons fire, so sweeping a set of changes that it creates new ways for the higher-level entities-the symbols-to trigger one another.
To parallel this in a computer system, a higher-level program would have to have some way of creating changes inside the "demon" that is carrying its program out. This is utterly foreign to the present style i computer science of implementing one level above another in a strictly vertical, sealed-off fashion. The ability of a higher level to loop back and

affect lower levels-its own underpinnings-is a kind of magic trick which we feel is very close to the core of consciousness. It will perhaps one day prove to be a key element in the push toward ever-greater flexibility in computer design, and of course in the approach toward artificial intelligence. In particular, a satisfactory answer to the question of what "understanding" really means will undoubtedly require a much sharper delineation of the ways in which different levels in a symbol-manipulating system can depend on and affect one another. All in all, these concepts have, proven elusive, and a clear understanding of them is probably a good ways off yet.
In this rather confusing discussion of many levels, you may have started to wonder what in the world "level" really means. It is a most difficult question. As long as levels are sealed off from each other, like Searle's demon and the Chinese-speaking woman, it is fairly clear. When they begin to blur, beware! Searle may admit that there are two levels in his thought experiment, but he is reluctant to admit that there are two occupied points of view-two genuine beings that feel and "have experience." He is worried that once we admit that some computational systems might have experiences, that would be a Pandora's box and all of a sudden "mind would be everywhere"-in the churning of stomachs, livers, automobile engines, and so on.
Searle seems to believe that any system whatsoever can be ascribed beliefs and feelings and so on, if one looks hard enough for a way to describe the system as an instantiation of an AI program. Obviously, that would be a disturbing notion, leading the way to panpsychism. Indeed, Searle believes that the Al people have unwittingly committed themselves to a panpsychic vision of the world.
Searle's escape from his self-made trap is to maintain that all those "beliefs" and "feelings" that you will uncover in inanimate objects and so forth when you begin seeing mind everywhere are not genuine but "pseudo." They lack intentionality! They lack the causal powers of the brain! (Of course, Searle would caution others to beware of confusing these notions with the naively dualistic notion of "soul.")
Our escape is to deny that the trap exists at all. It is incorrect to see minds everywhere. We say: minds do not lurk in car engines or livers any more than brains lurk in car engines and livers.
It is worthwhile expanding on this a little. If you can see all the complexity of thought processes in a churning stomach, then what's to prevent you from reading the pattern of bubbles in a carbonated beverage as coding for the Chopin piano concerto in E minor? And don't the holes in pieces of Swiss cheese code for the entire history of the United States? Sure they do-in Chinese as well as in English. After all, all things

are written everywhere! Bach's Brandenburg concerto no. 2 is coded for in the structure of Hamlet-and Hamlet was of course readable (if you' only known the code) from the structure of the last piece of birthday cake you gobbled down.
The problem is, in all these cases, that of specifying the code without knowing in advance what you want to read. For otherwise, you could pull a description of anyone's mental activity out of a baseball game or a blade of grass by an arbitrarily constructed a posteriori code. But this is not science.
Minds come in different grades of sophistication, surely, but minds worth calling minds exist only where sophisticated representational systems exist, and no describable mapping that remains constant in time will reveal a self-updating representational system in a car engine or a liver. Perhaps one could read mentality into a rumbling car engine in somewhat the way that people read extra meanings into the structures of the Great Pyramids or Stonehenge, the music of Bach, Shakespeare's plays, and so on-namely, by fabricating far-fetched numerological mapping schemes that can be molded and flexed whenever needed to fit the desires of the interpreter. But we doubt that that is what Searle intends (we do grant that he intends).
Minds exist in brains and may come to exist in programmed machines. If and when such machines come about, their causal powers will derive not from the substances they are made of, but from their design and the programs that run in them. And the way we will know they have those causal powers is by talking to them and listening carefully to what they have to say.

D.R.H.

Chapter 21: The Circular Ruins

2007-02-14T05:50:00.000-08:00

And if he left off dreaming about you . . .
--Through the Looking Glass VI

No one saw him disembark in the unanimous night, no one bamboo canoe sinking into the sacred mud, but within a few days was unaware that the silent man came from the South and that was one of the infinite villages upstream, on the violent moue where the Zend tongue is not contaminated with Greek and w rosy is infrequent. The truth is that the obscure man kissed came up the bank without pushing aside (probably without f brambles which dilacerated his flesh, and dragged himself, nauseous and bloodstained, to the circular enclosure crowned by a stone tiger which once was the color of fire and now was that of ashes. was a temple, long ago devoured by fire, which the malarial jungle had profaned and whose god no longer received the homage of stranger stretched out beneath the pedestal. He was awakened by high above. He evidenced without astonishment that his wounds had closed; he shut his pale eyes and slept, not out of bodily weakness of determination of will. He knew that this temple was the place, by his invincible purpose; he knew that, downstream, the incessant trees had not managed to choke the ruins of another propitious temple gods were also burned and dead; he knew that his immediate obligation

"The Circular Ruins," translated by James E. Irby, from Labyrinths: Selected Stories and Others Writings, edited by Donald E. Yates and James E. Irby. Copyright © 1962 by New Publishing Corporation. Reprinted by permission of New Directions, New York.

Was to sleep• Towards midnight he was awakened by the disconsolate cry bird. Prints of bare feet, some figs and a jug told him that men of the region had respectfully spied upon his sleep and were solicitous of favor or feared his magic. He felt the chill of fear and sought out a al niche in the dilapidated wall and covered himself with some unknown leaves.
The purpose which guided him was not impossible, though it was supernatural. He wanted to dream a man: he wanted to dream him with .1inute integrity and insert him into reality. This magical project had exhausted the entire content of his soul; if someone had asked him his own name or any trait of his previous life, he would not have been able to answer. The uninhabited and broken temple suited him, for it was a minimum of visible world; the nearness of the peasants also suited him, for they would see that his frugal necessities were supplied. The rice and fruit of their tribute were sufficient sustenance for his body, consecrated to the sole task of sleeping and dreaming.
At first, his dreams were chaotic; somewhat later, they were of a dialectical nature. The stranger dreamt that he was in the center of a circular amphitheater which in some way was the burned temple: clouds of silent students filled the gradins; the faces of the last ones hung many centuries away and at a cosmic height, but were entirely clear and precise. The man was lecturing to them on anatomy, cosmography, magic; the countenances listened with eagerness and strove to respond with understanding, as if they divined the importance of the examination which would redeem one of them from his state of vain appearance and interpolate him into the world of reality. The man, both in dreams and awake, considered his phantoms' replies, was not deceived by impostors, divined a growing intelligence in certain perplexities. He sought a soul which would merit participation in the universe.
After nine or ten nights, he comprehended with some bitterness that he could expect nothing of those students who passively accepted his doctrines, but that he could of those who, at times, would venture a reasonable contradiction. The former, though worthy of love and affection, could not rise to the state of individuals; the latter pre-existed somewhat more. One afternoon (now his afternoons too were tributaries of sleep, now he remained awake only for a couple of hours at dawn) he dismissed the vast illusory college forever and kept one single student. lie was a silent boy, sallow, sometimes obstinate, with sharp features which reproduced those of the dreamer. He was not long disconcerted by his companions' sudden elimination; his progress, after a few special lessons, astounded his teacher. Nevertheless, catastrophe ensued. The man emerged from sleep one day as if from a viscous desert, looked at

the vain light of afternoon, which at first he confused with and understood that he had not really dreamt. All that night the intolerable lucidity of insomnia weighed upon him. He plore the jungle, to exhaust himself, amidst the hemlocks, he was scarcely able to manage a few snatches of feeble sleep, fleetingly mottled with some rudimentary visions which were useless. He tried to convoke the college and had scarcely uttered a few brief words of exhortation when it became deformed and was extinguished. In his almost perpetual sleeplessness, his old eyes burned with tears of anger.
He comprehended that the effort to mold the incoherent and vertiginous matter dreams are made of was the most arduous task a man could undertake, though he might penetrate all the enigmas of the upper and lower orders: much more arduous than weaving a rope of sand or coining the faceless wind. He comprehended that an initial failure was; inevitable. He swore he would forget the enormous hallucination which had misled him at first, and he sought another method. Before putting it in effect he dedicated a month to replenishing the powers his delirium had wasted. He abandoned any premeditation of dreaming and, almost at o able to sleep for a considerable part of the day. The few times he dreamt during this period, he did not take notice of the dreams. To take up his task again, he waited until the moon's disk was perfect. Then in the afternoon, he purified himself in the waters of the river, worshipped the planetary gods, uttered the lawful syllables of a powerful name a Almost immediately, he dreamt of a beating heart.
He dreamt it as active, warm, secret, the size of a closed fist, o color in the penumbra of a human body as yet without face or sex with minute love he dreamt it, for fourteen lucid nights. Each night he perceived it with greater clarity. He did not touch it, but limited himself to witnessing it, observing it, perhaps correcting it with his eyes perceived it, lived it, from many distances and many angles. On the fourteenth night he touched the pulmonary artery with his finger, and then the whole heart, inside and out. The examination satisfied him. Deliberately, he did not dream for a night; then he took the heart again, the name of a planet and set about to envision another of the principal organs. Within a year he reached the skeleton, the eyelids. The innumerable hair was perhaps the most difficult task. He dreamt a complete man, a youth, but this youth could not rise nor did he speak nor could his eyes. Night after night, the man dreamt him as asleep.
In the Gnostic cosmogonies, the demiurgi knead and mold a red Adam who cannot stand alone; as unskillful and crude and elementary as this Adam of dust was the Adam of dreams fabricated by the magician’s nights of effort. One afternoon, the man almost destroyed his work, but

then repented. (It (It would have been better for him had he destroyed it.) Once he had completed his supplications to the numina of the earth and the river, he threw himself down at the feet of the effigy which was perhaps a tiger and perhaps a horse, and implored its unknown succor. That twilight, he dreamt of the statue. He dreamt of it as a living, tremulous thing: it was not an atrocious mongrel of tiger and horse, but both these vehement creatures at once and also a bull, a rose, a tempest. This multiple god revealed to him that its earthly name was Fire, that in the circular temple (and in others of its kind) people had rendered it sacrifices and cult and that it would magically give life to the sleeping phantom, in such a way that all creatures except Fire itself and the dreamer would believe him to be a man of flesh and blood. The man was ordered by the divinity to instruct his creature in its rites, and send him to the other broken temple whose pyramids survived downstream, so that in this deserted edifice a voice might give glory to the god. In the dreamer's dream, the dreamed one awoke.
The magician carried out these orders. He devoted a period of time (which finally comprised two years) to revealing the arcana of the universe and of the fire cult to his dream child. Inwardly, it pained him to be separated from the boy. Under the pretext of pedagogical necessity, each day he prolonged the hours he dedicated to his dreams. He also redid the right shoulder, which was. perhaps deficient. At times, he was troubled by the impression that all this had happened before . . . In general, his days were happy; when he closed his eyes, he would think:
Now I shall be with my son. Or, less often: The child I have engendered awaits me and will not exist if I do not go to him.
Gradually, he accustomed the boy to reality. Once he ordered him to place a banner on a distant peak. The following day, the banner flickered from the mountain top. He tried other analogous experiments, each more daring than the last. He understood with certain bitterness that his son was ready-and perhaps impatient-to be born. That night he kissed him for the first time and sent him to the other temple whose debris showed white downstream, through many leagues of inextricable jungle and swamp. But first (so that he would never know he was a phantom, so that he would be thought a man like others) he instilled into him a complete oblivion of his years of apprenticeship.
The man's victory and peace were dimmed by weariness. At dawn and at twilight, he would prostrate himself before the stone figure, imagining perhaps that his unreal child was practicing the same rites, in other circular ruins, downstream; at night, he would not dream, or would dream only as all men do. He perceived the sounds and forms of the universe with a certain colorlessness: his absent son was being nurtured

with these diminutions of his soul. His life's purpose was complete; man persisted in a kind of ecstasy. After a time, which some narrators of his story prefer to compute in years and others in lustra, he was awakened one midnight by two boatmen; he could not see their faces, but they him of a magic man in a temple of the North who could walk upon and not be burned. The magician suddenly remembered the words o god. He recalled that, of all the creatures of the world, fire was the one that knew his son was a phantom. This recollection, at first soot finally tormented him. He feared his son might meditate on his abnormal privilege and discover in some way that his condition was that of a mere image. Not to be a man, to be the projection of another man's dream what a feeling of humiliation, of vertigo! All fathers are interested in children they have procreated (they have permitted to exist) in confusion or pleasure; it was natural that the magician should fear for future of that son, created in thought, limb by limb and feature by feature in a thousand and one secret nights.
The end of his meditations was sudden, though it was foretold to certain signs. First (after a long drought) a faraway cloud on a hill, light and rapid as a bird; then, toward the south, the sky which had the rose color of the leopard's mouth; then the smoke which corroded the metallic nights; finally, the panicky flight of the animals. For what was happening had happened many centuries ago. The ruins of the fire god's sanctuary were destroyed by fire. In a birdless dawn the magician saw the concentric blaze close round the walls. For a moment, he thought of taking refuge in the river, but then he knew that death was coming to crown his old-age; and absolve him of his labors. He walked into the shreds of flame. But they did not bite into his flesh, they caressed him and engulfed him without heat or combustion. With relief, with humiliation, with terror he understood that he too was a mere appearance, dreamt by another.

Jorge Luis Borges

Reflections

Borges's epigraph is drawn from a passage in Lewis Carroll's Through the Looking Glass worth quoting in full.

Here she checked herself in some alarm, at hearing something that sounded to her like the puffing of a large steam-engine in the wood near them, though she

feared it was more likely to be a wild beast. "Are there any lions or tigers about
here?" she asked timidly.
"It's only the Red King snoring," said Tweedledee.
"Come and look at him!" the brothers cried, and they each took one of Alice's hands, and led her up to where the King was sleeping.
"Isn't he a lovely sight?" said Tweedledum.
Alice couldn't say honestly that he was. He had a tall red night-cap on, with a tassel, and he was lying crumpled up into a sort of untidy heap, and snoring loud-"fit to snore his head off!" as Tweedledum remarked.
"I'm afraid he'll catch cold with lying on the damp grass," said Alice, who
was a very thoughtful little girl.
"He's dreaming now," said Tweedledee: "and what do you think he's dreaming about?"
Alice said "Nobody can guess that."
"Why, about you!" Tweedledee exclaimed, clapping his hands triumphantly.
"And if he left off dreaming about you, where do you suppose you'd be?" "Where I am now, of course," said Alice.
"Not you!" Tweedledee retorted contemptuously. "You'd be nowhere. Why you're only a sort of thing in his dream!"
"If that there King was to wake," added Tweedledum, "you'd go out-bang!
just like a candle!"
"I shouldn't!" Alice exclaimed indignantly. "Besides, if I'm only a sort of
thing in his dream, what are you, I should like to know?"
"Ditto," said Tweedledum.
"Ditto, ditto!" cried Tweedledee.
He shouted this so loud that Alice couldn't help saying "Hush! You'll be
waking him, I'm afraid, if you make so much noise."
"Well, it's no use your talking about waking him," said Tweedledum, "when you're only one of the things in his dream. You know very well you're not real."
"I am real!" said Alice, and began to cry.
"You won't make yourself a bit realler by crying," Tweedledee remarked: there's nothing to cry about."

"If I wasn't real," Alice said-half-laughing through her tears, it all seem so ridiculous-"I shouldn't be able to cry."
"I hope you don't suppose those are real tears?" Tweedledum interrupt in a tone of great contempt.

Rene Descartes asked himself whether he could tell for certain he wasn't dreaming. "When I consider these matters carefully, I realize so clearly that there are no conclusive indications by which waking can be distinguished from sleep that I am quite astonished, and bewilderment is such that it is almost able to convince me that I sleeping."
It did not occur to Descartes to wonder if he might be a character in someone else's dream, or, if it did, he dismissed the idea out of hand Why? Couldn't you dream a dream with a character in it who was not you but whose experiences were a part of your dream? It is not easy to know how to answer a question like that. What would be the difference between dreaming a dream in which you were quite unlike your waking self-much older or younger, or of the opposite sex-and dreaming a dream in which the main character (a girl named Renee, let's say), the character from whose "point of view" the dream was "narrated," was simply not you b merely a fictional dream character, no more real than the dream-drag chasing her? If that dream character were to ask Descartes's question, a wonder if she were dreaming or awake, it seems the answer would be the she was not dreaming, nor was she really awake; she was just dream When the dreamer, the real dreamer, wakes up, she will be annihilated But to whom would we address this answer, since she does not really ex! at all, but is just a dream character?
Is this philosophical play with the ideas of dreaming and reality just idle? Isn't there a no-nonsense "scientific" stance from which we objectively distinguish between the things that are really there and mere fictions? Perhaps there is, but then on which side of the divide we put ourselves? Not our physical bodies, but our selves?
Consider the sort of novel that is written from the point of view a fictional narrator-actor. Moby Dick begins with the words "Call Ishmael," and then we are told Ishmael's story by Ishmael. Call whom Ishmael? Ishmael does not exist. He is just a character in Melville's novel Melville is, or was, a perfectly real self, and he created a fictional self who calls himself Ishmael-but who is not to be numbered among the real things, the things that really are. But now imagine, if you can, a novel writing machine, a mere machine, without a shred of consciousness selfhood. Call it the JOHNNIAC. (The next selection will help you imagine me such a machine, if you cannot yet convince yourself you can do it)

Suppose the novel that clattered out of the JOHNNIAC on its high-speed printer started: "Call me Gilbert," and proceeded to tell Gilbert's story from Gilbert's point of view. Call whom Gilbert? Gilbert is just a fictional character, a nonentity with no real existence, though we can go along with the fiction and talk about, learn about, worry about "his" adventures, problems, hopes, fears, pains. In the case of Ishmael, we may have supposed his queer, fictional, quasi-existence depended on the real existence of Melville's self. No dream without a dreamer to dream it seems to be Descartes' discovery. But in this case we do seem to have a dream-a fiction, in any case-with no real dreamer or author, no real self with whom we might or might not identify Gilbert. So in such an extraordinary case as the novel-writing machine there might be created a merely fictional self with no real self behind the act of creation. (We can even suppose the JOHNNIAC's designers had no idea what novels it would eventually write.)
Now suppose our imagined novel-writing machine is not just a sedentary, boxy computer, but a robot. And suppose-why not?-that the text of the novel is not typed but "spoken" from a mechanical mouth. Call this robot the SPEECHIAC. And suppose, finally, the tale we learn from the SPEECHIAC about the adventures of Gilbert is a more or less true story of the "adventures" of the SPEECHIAC. When it is locked in a closet, it says: "I am locked in the closet! Help me!" Help whom? Help Gilbert. But Gilbert does not exist; he is just a fictional character in the SPEECHIAC's peculiar narration. Why, though, should we call this account fiction, since there is a quite obvious candidate in sight to be Gilbert: the person whose body is the SPEECHIAC? In "Where Am I?" Dennett called his body Hamlet. Is this a case of Gilbert having a body called the SPEECHIAC, or of the SPEECHIAC calling itself Gilbert?
Perhaps we are being tricked by the name. Naming the robot "Gilbert" may be just like naming a sailboat "Caroline" or a bell "Big Ben" or a program "ELIZA." We may feel like insisting that there is no person named Gilbert here. What, though, aside from bio-chauvinism, grounds our resistance to the conclusion that Gilbert is a person, a person created, in effect, by the SPEECHIAC's activity and self-presentation in the world?
"Is the suggestion then that I am my body's dream? Am 1 just a fictional character in a sort of novel composed by my body in action?" That would be one way of getting at it, but why call yourself fictional? Your brain, like the unconscious novel-writing machine, cranks along, doing its physical tasks, sorting the inputs and the outputs without a glimmer of what it is up to. Like the ants that compose Aunt Hillary in "Prelude, Ant Fugue,"

it doesn't "know" it is creating you in the process, but there you emerging from its frantic activity almost magically.
This process of creating a self at one level out of the relatively mindless and uncomprehending activities amalgamated at another 1evel is vividly illustrated in the next selection by John Searle, though he firmly resists that vision of what he is showing.

D.C.D