Further Reading

Almost every topic that arises in The Mind's I has been explored in greater detail in the explosively growing literature of "cognitive science"-philosophy of mind, psychology, artificial intelligence, and the neurosciences, to mention the central fields. There has also been a mountain of science fiction on these themes, of course, but we will not attempt to survey that literature in this catalogue of the best and most readable recent books and articles, ranging from clinical studies of strange cases through experimental work to theoretical and speculative explorations. The catalogue is organized by topics in the order in which they arise in the preceding selections. Each piece we list will in turn lead to additional relevant literature through its citations. Those who pursue these leads will discover a huge tree of intricately intertwined branches of discovery, speculation, and argument. That tree will not include everything that has been written on these topics, certainly, but whatever it neglects will have escaped the attention of most of the experts as well.

Introduction

The idea of body-switching has fascinated philosophers for centuries. John Locke, in his Essay Concerning Human Understanding (1690), asked himself what would happen if "the soul of a prince" were to

"enter and inform the body of a cobbler"-taking the prince's memq ries along with it. The theme has had dozens of variations since then Two fine anthologies, full of imagined cases of brain transplants, per son splitting, person fusing (two or more people merging into one pe son with several sets of memories and tastes), and person."duplicatin are Personal Identity (1975), edited by John Perry, and The Identities o Persons (1976), edited by Amelie O. Rorty, both in paperback from the University of California Press at Berkeley. Another good book is Ber nard Williams's Problems of the Se 4( (New York: Cambridge Universit Press, 1973).
Do minds or selves really exist-over and above the atoms an molecules? Such ontological questions (questions concerning the type of things that can be said to exist and the ways in which things can exist have been a major preoccupation of philosophers since Plato's day. Prob ably the most influential of today's hard-nosed, tough-minded scientific ontologists is Willard V. O. Quine, of Harvard University. His classic paper "On What There Is" first appeared in 1948 in the Review of Meta physics. It is reprinted in his collection of essays, From a Logical Point of View (Cambridge, Mass.: Harvard University Press, 1953). Quine's Word and Object (Cambridge, Mass.: MIT Press, 1960) and Ontological Relativity and Other Essays (New York: Columbia University Press, 1969) contain later, elaborations of his uncompromising ontological stand. An amusing dialogue in which a tough-minded materialist gets tied in knots is "Holes' by David and Stephanie Lewis, in the Australasian Journal of Philosophy (vol. 48, 1970, pp. 206-212). If holes are things that exist, what about voices. What are they? This question is discussed in the first chapter of Daniel Dennett's Content and Consciousness (London: Routledge & Kegan Paul; Atlantic Highlands, NJ.: Humanities Press, 1969), where the claim is advanced that minds enjoy the same sort of existence as voices-not problematic (like ghosts or goblins) but not just a matter of matter, either.
The literature on consciousness will be introduced by subtopics later in this chapter. The discussion of consciousness in the Introduction is drawn from an entry on that topic by Dennett forthcoming in the Oxford Companion to the Mind (New York: Oxford University Press), an encyclopedia of current understanding of the mind, edited by R. L. Gregory. The quotation of E. R. John's definition of consciousness is from R. W. Thatcher and E. R. John, Foundations of Cognitive Processes (Hillsdale, N .J.: Erlbaum, 1977, p. 294), and the dichotic listening experiment discussed is reported in J.R. Lackner and M. Garrett, "Resolving Ambiguity: Effects of Biasing Context in the Unattended Ear," Cognition (1973, pp.
359-372).

Part I. A Sense of Self
Borges draws our attention to different ways of thinking about
oneself. A good entry to the recent work in philosophy mentioned in the
Reflections is "Who, Me?" by Steven Boer and William Lycan, in The
Philosophical Review (vol. 89, 1980, pp. 427-466). It has an extensive
bibliography that includes the pioneering work of Hector-Neri Castaneda
and Peter Geach, and the fine recent work by John Perry and David Lewis.
Harding's strange ruminations on having no head find an echo in the psychological theories of the late James J. Gibson, whose last book, The Ecological Approach to Visual Perception (Boston: Houghton Mifflin, 1979), contains many striking observations-and results of experiments -about the information one gets about oneself (one's location, the orientation of one's head, even the important role of that blurry bit of nose one can see out of the corner of one's eye) from visual perception. See especially chapter 7, "The Optical Information for Self-Perception." For a recent criticism of Gibson's ideas, see Shimon Ullman, "Against Direct Perception," in The Behavioral and Brain Sciences (September, 1980, pp. 373-415). An excellent introduction to the Taoistic and Zen theory of mind and existence is Raymond Smullyan's The Tao is Silent (New York: Harper & Row, 1975). See also Paul Reps' Zen Flesh, Zen Bones (New York: Doubleday Anchor).
The physical background for the quantum-mechanical ideas presented in Morowitz's article and the accompanying Reflection is available at several levels of difficulty. A stimulating elementary presentation is that by Adolph Baker in Modern Physics and Anti-physics (Reading, Mass.: Addison-Wesley, 1970). And there is Richard Feynman's The Character of Physical Law (Cambridge, Mass.: MIT Press, 1967). At an intermediate level, using a bit of mathematics, are J. Jauch's elegant dialogues Are Quanta Real? (Bloomington: Indiana University Press, 1973) and The Feynman Lectures in Physics, vol. III, by Richard Feynman, Robert Leighton, and Matthew Sands (Reading, Mass.: Addison-Wesley, 1963). An advanced treatise is the monograph The Conceptual Development of Quantum Mechanics by Max Jammer (New York: McGraw-Hill, 1966). There is also a furtherout book, edited by Ted Bastin, called Quantum Theory and Beyond: Essays and Discussions Arising from a Colloquium (Cambridge, Eng.: -Cambridge
Univ. Press, 1971) containing many speculative selections. Eugene Wigner, one of the major figures in physics this century, has devoted an entire selection, in his book of essays entitled Symmetries and Reflections (Cambridge, Mass.: MIT press, 1970), to the subject of "Epistemology and Quantum Mechanics."

Hugh Everett's original paper is found, together with discussions b other physicists, in The Many-Worlds Interpretation of Quantum Mechanics (Princeton, N .J.: Princeton University Press, 1973), edited by B. S. Dewitt and N. Graham. A recent and much easier book on these puzzling,Splitting worlds is Paul Davies' Other Worlds (New York: Simon & Schuster, 1981).
The strange problem of personal identity under such conditions o branching has been explored, indirectly, in a high-powered but lively debate among philosophers over the claims made by the philosopher and logician Saul Kripke in his classic monograph "Naming and Necessity," which first appeared in 1972 in D. Davidson and G. Harman, eds., The Semantics of Natural Language (Hingham, Mass.: Reidel, 1972), and has just been reprinted, with additional material, as a book by Kripke, Naming and Necessity (Cambridge, Mass.: Harvard University Press, 1980). In the Reflections, an issue is raised that must have occurred to you before: If my parents hadn't met, I'd never have existed-or could I have been the child of some other parents? Kripke argues (with surprising persuasiveness) that although someone exactly like you might have been born at a different time to different parents-or even to your own parents-that person could not have been you. Where, when, and to whom you were born is part of your essence. Douglas Hofstadter, Gray Clossman, and Marsha Meredith explore this strange terrain in "Shakespeare's Plays Weren't Written by Him, but by Someone Else of the Same Name" (Indiana University Computer Science Dept. Technical Report 96) and Daniel Dennett casts some doubt on the enterprise in "Beyond Belief," forthcoming in Andrew Woodfield, ed., Thought and Object (New York: Oxford University Press, 1981). Meaning, Reference and Necessity (New York: Cambridge University Press, 1975), edited by Simon Blackburn, is, a good anthology of work on the issue, and the topic continues to be analyzed in current and forthcoming articles in major philosophy journals.
Morowitz cites recent speculation about the sudden emergence of a special sort of self-consciousness in evolution-a discontinuity in the development of our remote ancestors. Certainly the boldest and most ingeniously argued case for such a development is Julian Jaynes's The Origins of Consciousness in the Breakdown of the Bicameral Mind (Boston: Houghton Mifflin, 1976), in which he argues that consciousness of the familiar, typically human sort is a very recent phenomenon, whose onset is datable in historical times, not biological eons. The human beings told of in Homer's Iliad, Jaynes insists, were not conscious! That is not to say they were asleep, or unperceiving, of course, but that they had nothing like what we think of as our inner lives. Even if Jaynes has overstated his


Further Reading 409
case (as most commentators think), he has posed fascinating questions and drawn attention to important facts and problems hitherto unconsidered by thinkers on these topics. Incidently, Friedrich Nietzsche expressed a similar view of the relation of consciousness and social and linguistic practices in Die frohliche Wissenschaft (1882), translated by Walter Kaufmann as The Gay Science (New York: Random House, 1974).
Part II. Soul Searching
The Turing test has been the focus of many articles in philosophy and artificial intelligence. A good recent discussion of the problems it raises is "Psychologism and Behaviorism" by Ned Block, in The Philosophical Review (January 1981, pp. 5-43). Joseph Weizenbaum's famous ELIZA program, which simulates a psychotherapist with whom one can hold an intimate and therapeutic conversation (typing on a computer terminal), is often discussed as the most dramatic real-life example of a computer "passing" the Turing test. Weizenbaum himself is appalled by the idea, and in Computer Power and Human Reason (San Francisco: Freeman, 1976), he offers trenchant criticism of those who-in his opinion-misuse the Turing test. Kenneth M. Colby's program PARRY, the simulation of a paranoid patient that "passed" two versions of the Turing test, is described in his "Simulation of Belief Systems," in Roger C. Schank and Kenneth M. Colby, eds., Computer Models of Thought and Language (San Francisco: Freeman, 1973). The first test, which involved showing transcripts of PARRY's conversations to experts, was amusingly attacked by Weizenbaum in a letter published in the Communications of the Association for Computing Machinery (vol. 17, no. 9, September 1974, p. 543). Weizenbaum claimed that by Colby's reasoning, any electric typewriter is a good
scientific model of infantile autism: type in a question and it just sits there
and hums. No experts on autism could tell transcripts of genuine at
tempts to communicate with autistic children from such futile typing
exercises! The second Turing test experiment responded to that criti
cism, and is reported in J. F. Heiser, K. M. Colby, W. S. Faught, and K.
C. Parkinson, "Can Psychiatrists Distinguish a Computer Simulation of
Paranoia from the Real Thing?" in the Journal of Psychiatric Research (vol.
15, 1980, pp. 149-62).
Turing's "Mathematical Objection" has produced a flurry of litera
ture on the relation between metamathematical limitative theorems and
the possibility of mechanical minds. For the appropriate background in

logic, see Howard De Long's A Profile of Mathematical Logic (Reading, Mass.: Addison-Wesley, 1970). For an expansion of Turing's objection, see J. R. Lucas's notorious article "Minds, Machines, and Godel," reprinted in the stimulating collection Minds and Machines, edited,by Alan Ross Anderson (Engelwood Cliffs, NJ.: Prentice-Hall, 1964). De Long's excellent annotated bibliography provides pointers to the furor created by Lucas's paper. See also Godel, Escher, Bach: an Eternal Golden Braid by Douglas R. Hofstadter (New York: Basic Books, 1979) and Mechanism, Mentalism, and Metamathematics by Judson Webb (Hingham, Mass.: D. Reidel, 1980).
The continuing debate on extrasensory perception and other paranormal phenomena is now followable on a regular basis in the lively quarterly journal The Skeptical Enquirer.
The prospects of ape language have been the focus of intensive research and debate in recent years. Jane von Lawick Goodall's observations in the wild, In the Shadow of Man (Boston: Houghton Mifflin, 1971) and early apparent breakthroughs in training laboratory animals to use sign language or other artificial languages by Allen and Beatrice Gardner, David Premack, Roger Fouts, and others led to hundreds of articles and books by scores of researchers and their critics. The experiment with high school students is reported in E. H. Lenneberg, "A Neuropsychological Comparison between Man, Chimpanzee and Monkey," Neuropsychologia (vol. 13, 1975, p. 125). Recently Herbert Terrace, in Nim: A Chimpanzee Who Learned Sign Language (New York: Knopf, 1979), managed to throw a decidedly wet blanket on this enthusiasm with his detailed analysis of the failures of most of this research, including his own efforts with his chimpanzee, Nim Chimpsky, but the other side will surely fight back in forthcoming articles and books. The Behavioral and Brain Sciences (BBS) of December 1978 is devoted to these issues and contains major articles by Donald Griffin, author of The Question of Animal Awareness (New York: Rockefeller Press, 1976), by David Premack and Guy Woodruff, and by Duane Rumbaugh, Sue Savage-Rumbaugh, and Sally Boysen. Accompanying these articles are a host of critical commentaries by leading researchers in linguistics, animal behavior, psychology and philosophy, and replies by the authors. In BBS, a new interdisciplinary journal, every article is followed by dozens of commentaries by other experts and a reply by the author. In a field as yeasty and controversial as cognitive science, this is proving to be a valuable format for introducing the disciplines to each other. Many other BBS articles in addition to those mentioned here provide excellent entry points into current research.
Although there is clearly a link of great importance between consciousness and the capacity to use language, it is important to keep


Jthese issues separate. Self-consciousness in animals has been studied experimentally. In an interesting series of experiments, Gordon Gallup established that chimpanzees can come to recognize themselves in mirrors-and they recognize themselves as themselves too, as he demonstrated by putting dabs of paint on their foreheads while they slept. When they saw themselves in the mirrors, they immediately reached up to touch their foreheads and then examined their fingers. See Gordon G. Gallup, r., "Self-recognition in Primates: A Comparative Approach to the Bidirection Properties of Consciousness," American Psychologist (vol. 32, (5), 1977, pp. 329-338). For a recent exchange of views on the role of language in human consciousness and the study of human thinking, see Richard Nisbett and Timothy De Camp Wilson, "Telling More Than We Know: Verbal Reports on Mental Processes," Psychological Review (vol. 84, (3), 1977, pp. 321-359) and K. Anders Ericsson and Herbert Simon, "Verbal Reports as Data," Psychological Review (vol. 87, (3), May 1980, pp. 215-250).
Many robots like the Mark III Beast have been built over the years. One at Johns Hopkins University was in fact called the Hopkins Beast. For a brief illustrated review of the history of robots and an introduction to current work on robots and artificial intelligence, see Bertram Raphael, The Thinking Computer: Mind Inside Matter (San Francisco: Freeman, 1976). Other recent introductions to the field of Al are Patrick Winston's Artificial Intelligence (Reading, Mass.: Addison-Wesley, 1977), Philip C. Jackson's Introduction to Artificial Intelligence (Princeton, N .J.: Petrocelli Books, 1975), and Nils Nilsson's Principles ofArticial Intelligence (Menlo Park,Ca.: Tioga, 1980). Margaret Boden's Artificial Intelligence and Natural Man (New York: Basic Books, 1979) is a fine introduction to Al from a philosopher's point of view. A new anthology on the conceptual issues confronted by artificial intelligence is John Haugeland, ed., Mind Design: Philosophy, Psychology, Artificial Intelligence (Montgomery, Vt.: Bradford, 1981), and an earlier collection is Martin Ringle, ed., Philosophical Perspectives on Artificial Intelligence (Atlantic Highlands, NJ.: Humanities Press, 1979). Other good collections on these issues are C. Wade Savage, ed., Perception and Cognition: Issues in the Foundations of Psychology (Minneapolis: University of Minnesota Press, 1978) and Donald E. Norman, ed., Perspectives on Cognitive Science (Norwood, N .J.: Ablex, 1980).
One shouldn't ignore the critics of AI. In addition to Weizenbaum, who devotes several chapters of Computer Power and Human Reason to an attack on Al, there is the philosopher Hubert Dreyfus, whose What Computers Can't Do (New York: Harper & Row, 2nd ed., 1979) is the most sustained and detailed criticism of the methods and presuppositions of the field. An entertaining and informative history of the birth of the field

is Pamela McCorduck's Machines Who Think: A Personal Inquiry into History and Prospects ofArticial Intelligence (San Francisco: Freeman, 197
Part III. From Hardware to Software
Dawkins's provocative views on genes as the units of selection hav
received considerable attention from biologists and philosophers of biol
ogy. Two good and relatively accessible discussions are William Wi
satt's "Reductionistic Research Strategies and Their Biases in the Unt
of Selection Controversy," in Thomas Nickles, ed., Scientific Discovery, vo
2, Case Studies (Hingham, Mass.: Reidel, 1980, pp. 213-59), and Elliot
Sober's "Holism, Individualism, and the Units of Selection," in Proceed',
ings of the Philosophy of Science Association (vol. 2, 1980).
There have been many attempts to establish different levels of de• scription of the brain and to describe the relations between them. Som pioneering attempts by neuroscientists are Karl Pribram's The Languages of the Brain (Engelwood Cliffs, NJ.: Prentice-Hall, 1971), Michael Arbib's
The Metaphorical Brain (New York: Wiley Interscience, 1972), and R. W Sperry's "A Modified Concept of Consciousness" in Psychological Review, (vol. 76, (6), 1969, pp. 532-536). Consciousness and Brain: A Scientific an Philosophical Inquiry (New York: Plenum, 1976), edited by G. Globus, G Maxwell, and I. Savodnick, includes several discussions of the problems faced by anyone who tries to relate brain-talk to mind-talk. An earlier work, yet still full of fresh insight, is Dean Wooldridge's Mechanical Man: The Physical Basis of Intelligent Life (New York: McGraw-Hill, 1968).
The general problem of levels of explanation in discussing mind and brain is one of the central themes of Hofstadter's Godel, Escher, Bach It is also the topic of the books The Sciences of the Artificial by Herbert Simon (Cambridge, Mass.: MIT Press, 2nd ed., 1981) and Hierarchy Theory, edited by Howard H. Pattee (New York: George Braziller, 1973).
Reduction and holism in biological systems such as ant colonies have been under debate for many decades. Back in 1911, William Morton Wheeler wrote an influential article entitled "The Ant-Colony as an Organism" in theJournal of Morphology (vol. 22, no. 2, 1911, pp. 307-325). More recently, Edward O. Wilson has written a remarkably thorough treatise on social insects, called The Insect Societies (Cambridge, Mass.: Harvard Univ. Press, Belknap Press, 1971). We are not aware of any literature exploring the intelligence of societies; for example, can an ant colony learn new tricks?


er Reading 473
The explicitly antireductionistic sentiment has been put forward vehemently by an international group whose most outspoken member is the novelist and philosopher Arthur Koestler. Together with J.R. Smythies, he has edited a volume called Beyond Reductionism (Boston: Beacon Press, 1969) and has stated his own position eloquently in Janus: A Summing Up (New York: Vintage, 1979), particularly the chapter entitled "Free Will in a Hierarchic Context."
join tjoin The quotations in the Reflections on "Prelude, Ant Fugue" are from Richard D. Mattuck, A Guide to Feynman Diagrams in the Many-Body Problem (New York: McGraw-Hill, 1976), and Inside the Brain (New York: Mentor, 1980), by William H. Calvin and George A. Ojemann. Aaron Sloman, who was probably the first person trained as a philosopher to he field of artificial intelligence, is the author of The Computer Revolution in Philosophy (Brighton, England: Harvester, 1979). Like many revolutionary manifestos, Sloman's book vacillates between declaring victory, declaring that victory is inevitable, and exhorting the reader to a difficult and uncertain campaign. Sloman's vision of the accomplishments and prospects of the movement is rose-tinted, but insightful. Other landmark work on systems of knowledge representation can be found in Lee W. Gregg, ed., Knowledge and Cognition (New York: Academic Press, 1974); Daniel G. Bobrow and Allan Collins, eds., Representation and Understanding (New York: Academic Press, 1975); Roger C. Schank and Robert P. Abelson, Scripts, Plans, Goals and Understanding (Hillsdale, NJ.: Erlbaum, 1977); Nicholas V. Findler, ed., Foundations of Semantic Networks (New York: Academic Press); Donald A. Norman and David Rumelhart, eds. Explorations in Cognition (San Francisco: W. H. Freeman, 1975); Patrick Henry Winston, The Psychology of Computer Vision (New York: McGraw-Hill, 1975); and the other books and articles on artificial intelligence mentioned in this chapter.
The strategy of speaking figuratively of homunculi, little people in the brain whose joint activity composes the activity of a single mind, is explored in detail in Daniel C. Dennett's Brainstorms (Montgomery, Vt.: Bradford Books, 1978). An early article in this vein was F. Attneave's "In Defense of Homunculi," in W. Rosenblith, ed., Sensory Communication,
(Cambridge, Mass.: MIT Press, 1960, pp. 777-782). William Lycan advances the cause of homunculi in "Form, Function, and Feel," in the Journal of Philosophy (vol. 78, (1), 1981, pp. 24-50). See also Ronald de
Sousa's "Rational Homunculi" in Rorty's The Identities of Persons.
Disembodied brains have long been a favorite philosophical fantasy.
In his Meditations (1641), Descartes presents the famous thought experi
ment of the evil demon or evil genius. "How do I know," he asks himself
in effect, "that I am not being tricked by an infinitely powerful evil demon

who wants to deceive me into believing in the existence of the external world (and my own body)?" Perhaps, Descartes supposes, the only thing that exists aside from the demon is his own immaterial mind-the minimal victim of the demon's deceit. In these more materialistic times the same question is often updated: How do I know that evil scientists haven't removed my brain from my head while I slept and put it in a life-support vat, where they are tricking it-me-with phony stimulation? Literally hundreds of articles and books have been written about Descartes's thought experiment with the evil demon. Two good recent books are Anthony Kenny's Descartes: A Study of his Philosophy (Random House,
1968), and Harry Frankfurt's Demons, Dreamers, and Madmen: The Defense of
Reason in Descartes' Meditations (Indianapolis: Bobbs-Merrill, 1970). A fine anthology is Willis Doney, ed., Descartes: a Collection of Critical Essays (New York: Macmillan, 1968). A particularly memorable and amusing discussion is O. K. Bouwsma's "Descartes' Evil Genius," in the Philosophical Review (vol. 58, 1949, pp. 141-151).
The "brain in the vat" literature, of which ZubotTs strange tale is a previously unpublished instance, has recently been rejuvenated with some new critical slants. See Lawrence Davis's "Disembodied Brains," in the Australasian Journal of Philosophy (vol. 52, 1974, pp. 121-132), and Sydney Shoemaker's "Embodiment and Behavior," in Rorty's The Identities of Persons. Hilary Putnam discusses the case at length in his new book, Reason, Truth and History (New York: Cambridge University Press, 1981), and argues that the supposition is not just technically outrageous but deeply, conceptually incoherent.
Part IV. Mind as Program
The theme of duplicate people-atom-for-atom replicas-has been picked up from fiction by philosophers, most notably by Hilary Putnam, who imagines a planet he calls Twin Earth, where each of us has an exact duplicate or Doppelganger, to use the German term Putnam favors. Putnam first presented this literally outlandish thought experiment in "The Meaning of `Meaning'," in Keith Gunderson, ed., Language, Mind and Knowledge (Minneapolis: University of Minnesota Press, 1975, pp. 131193), where he uses it to establish a surprising new theory of meaning. It is reprinted in the second volume of Putnam's collected papers, Mind, Language and Reality (New York: Cambridge University Press, 1975). While it seems that almost no philosopher takes Putnam's argument


urther Reading 475
jusseriously-that's what they all say-few can resist trying to say, at length, t where he has gone wrong. A provocative and influential article that exploits Putnam's fantasy is Jerry Fodor's intimidatingly entitled "Methodological Solipsism Considered as a Research Strategy in Cognitive Psychology," published, along with much furious commentary and rebuttal, in The Behavioral and Brain Sciences (vol. 3, no. 1, 1980, pp. 63-73). His comment on Winograd's SHRDLU, quoted in the Reflections on "Non Serviam," comes from this article, which is reprinted in Haugeland's
Mind Design.
Prosthetic vision devices for the blind, mentioned in the Reflections on both "Where Am I?" and "What is it Like to be a Bat?", have been under development for many years, but the best systems currently available are still crude. Most of the research and development has been done in Europe. A brief survey can be found in Gunnar Jansson's "Human Locomotion Guided by a Matrix of Tactile Point Stimuli," in G. Gordon, ed., Active Touch (Elmsford, N.Y.: Pergamon Press, 1978, pp. 263-271). The topic has been subjected to philosophical scrutiny by David Lewis in "Veridical Hallucination and Prosthetic Vision," in the Australasian Journal of Philosophy (vol. 58, no. 3, 1980, pp. 239-249).
Marvin Minsky's article on telepresence appeared in Omni in May 1980, pp. 45-52, and contains references to further reading.
When Sanford speaks of the classic experiment with inverting lenses, he is referring to a long history of experiments that began before the turn of the century when G. M. Stratton wore a device for several days that blocked vision in one eye and inverted it in the other. This and more recent experiments are surveyed in R. L. Gregory's fascinating and beautifully illustrated book, Eye and Brain (London: Weidenfeld and Nicolson, 3rd ed., 1977). Also see No Kohler's "Experiments with Goggles," in Scientific American (vol. 206, 1962, pp. 62-72). An up-to-date and very readable book on vision is John R. Frisby's Seeing: Illusion, Brain, and Mind
(Oxford: Oxford Univ. Press, 1980).
Godel sentences, self-referential constructions, "strange loops," and their implications for the theory of the mind are explored in great
detail in Hofstadter's Godel, Escher, Bach, and with some different twists
in Dennett's "The Abilities of Men and Machines," in Brainstorms. That
Godel's Theorem is a bulwark of materialism rather than of mentalism
is a thesis forcefully propounded in judson Webb's Mechanism, Mentalism,
and Metamathematics. A lighter but no less enlightening exploration of
such ideas is Patrick Hughes's and George Brecht's Vicious Circles and
Paradoxes (New York: Doubleday, 1975). C. H. Whitely's refutation of
Lucas's thesis is found in his article "Minds, Machines and GOdel: A
Reply to Mr. Lucas," published in Philosophy (vol. 37, 1962, p. 61).

Fictional objects have recently been the focus of considerable atten tion from philosophers of logic straying into aesthetics. See Terence Parsons, Nonexistent Objects (New Haven, Conn.: Yale University Press, 1980); David Lewis, "Truth in Fiction," in American Philosophical Quarterly (vol. 15, 1978, pp. 37-46); Peter van Inwagen, "Creatures of Fiction," also in American Philosophical Quarterly (vol. 14, 1977, pp. 299-308); Robert Howell, "Fictional Objects," in D. F. Gustafson and B. L. Tapscott, eds., Body, Mind, and Method: Essays in Honor of Virgil C. Aldrich (Hingham, Mass.: Reidel, 1979); Kendall Walton, "How Remote are Fictional Worlds from the Real World?" in TheJournal ofAesthetics andArt Criticism (vol. 37, 1978, pp. 11-23); and the other articles cited in them. Literary dualism, the view that fictions are real, has had hundreds of explorations in fiction. One of the most ingenious and elegant is Borges's "Tlon, Uqbar, Orbis Tertius," in Labyrinths (New York: New Directions, 1964), from which the selections by Borges in The Mind's I are all drawn.
All of the books on artificial intelligence mentioned earlier have detailed discussions of simulated worlds rather like the world described in "Non Serviam," except the worlds are much smaller (hard reality has a way of cramping one's style). See especially the discussion in Raphael's book, pp. 266-269. The vicissitudes of such "toy worlds" are also discussed by Jerry Fodor in "Tom Swift and his Procedural Grandmother," in his new collection of essays, RePresentations (Cambridge, Mass.: Bradford Books/MIT Press, 1981), and by Daniel Dennett in "Beyond Belief." The game of Life and its ramifications are discussed with verve by Martin Gardner in the "Mathematical Games" column of the October, 1970 issue of Scientific American (vol. 223, no.4, pp. 120-123).
Free will has of course been debated endlessly in philosophy. An anthology of recent work that provides a good entry into the literature is Ted Honderich, ed., Essays on Freedom of Action (London: Routledge & Kegan Paul, 1973). Two more recent articles that stand out appear together in the Journal of Philosophy (March 1980): Michael Slote's "Understanding Free Will," (vol. 77, pp. 136-151) and Susan Wolf's "Asymmetrical Freedom," (vol. 77, pp. 151-166). Even philosophers are often prone to lapse into the pessimistic view that no one can ever get anywhere in debates about free will-the issues are interminable and insoluble. This recent work makes that pessimism hard to sustain; perhaps one can


objbegin to see the foundations of a sophisticated new way of conceiving of ourselves both as free and rational agents, choosing and deciding our courses of action, and as entirely physical denizens of a physical environment, as much subject to the "laws of nature" as any plant or inanimate ect.
For more commentary on Searle's "Minds, Brains and Programs," see the September 1980 issue of The Behavioral and Brain Sciences in which it appeared. Searle's references are to the books and articles by Weizenbaum, Winograd, Fodor, and Schank and Abelson already mentioned in this chapter, and to Allen Newell and Herbert Simon, "GPS: A Program that Simulates Human Thought," in E. Feigenbaum and J. Feldman, eds., Computers and Thought (New York: McGraw Hill, 1963); John McCarthy, "Ascribing Mental Qualities to Machines," in Ringle's Philosophical Perspectives in Artificial Intelligence, and Searle's own papers, "Intentionality and the Use of Language," in A. Margolit, ed., Meaning and Use (Hingham, Mass.: Reidel, 1979), and "What is an Intentional State?" in Mind (vol. 88, 1979, pp. 74-92).
What it means to think in a language (or in several) is explored from a literary perspective in George Steiner's After Babel (New York: Oxford Univ. Press, 1975) and from a scientific perspective in The Bilingual Brain, by Martin L. Albert and Loraine K. Obler (New York: Academic Press, 1978). Simulation and emulation in computer science are lucidly explained in Andrew Tanenbaum's excellent text, Structured Computer Organization (Englewood Cliffs, NJ.: Prentice-Hall, 1976).
Bennett and Chaitin's mathematical theory of the limits on the speed of evolution of complex systems is sketched in G. J. Chaitin, "Algorithmic Information Theory," IBM Journal of Research and Development (vol. 21, no. 4, 1977, pp. 350-359).
For recent versions of dualism, see Karl Popper and John Eccles, The Self and Its Brain (New York: Springer-Verlag, 1977), and- Dennett's (caustic) review, in the Journal of Philosophy (vol. 76, (2), 1979, pp. 91-98). A keystone of Eccles's dualistic theory is Benjamin Libet's experimental work on the timing of the perception of stimuli (Science, vol. 158, 1967, pp. 1597-1600). This work has been vigorously criticized by Patricia Churchland in "On the Alleged Backwards Referral of Experiences and its Relevance to the Mind-Body Problem," in Philosophy of Science (vol. 48, no. 1, 1981). See Libet's response to Churchland: "The Experimental Evidence for a Subject Referral of a Sensory Experience, Backwards in Time: Reply to P. S. Churchland" (vol. 48, (2), 1981) and Churchland's Response to Libet (vol. 48, (3), 1981). Libet's work is also critically discussed by Chris Mortensen in "Neurophysiology and Experiences" in the Australasian Journal of Philosophy (1980, pp. 250-264).
Part V. Created Selves and Free Will

Two other recent attempts to provide empirical grounds for dualism have appeared in The Behavioral and Brain Sciences (with the usual barrage of expert counterattack and rejoinder): Roland Puccetti and Robert Dykes's "Sensory Cortex and the Mind-Brain Problem," BBS (vol. 3, 1978, pp. 337-376), and Roland Puccetti, "The Case for Mental Duality: Evidence from Split-Brain Data and other Considerations," BBS (1981).
Nagel addresses his musings on what it is like to be a bat against a "recent wave of reductionist euphoria," and cites as examples: J. J. C. Smart, Philosophy and Scientific Realism (London: Routledge & Kegan Paul, 1963); David Lewis, "An Argument for the Identity Theory," in Journal of Philosophy (vol. 63, 1966); Hilary Putnam, "Psychological Predicates," in Art, Mind, and Religion, edited by W. H. Capitan and D. D. Merrill (Pittsburgh: University of Pittsburgh Press, 1967), and reprinted in Putnam's Mind, Language and Reality; D. M. Armstrong, A Materialist Theory of the Mind (London: Routledge & Kegan Paul, 1968); and Daniel Dennett, Content and Consciousness. On the opposing side of the issue he cites Kripke's "Naming and Necessity," M. T. Thornton, "Ostensive Terms and Materialism," The Monist (vol. 56, 1972, pp. 193-214), and his own earlier reviews of Armstrong, in Philosophical Review (vol. 79, 1970, pp. 394-403), and Dennett, in Journal of Philosophy (vol. 69, 1972). Three other important papers in the philosophy of mind are cited by him: Donald Davidson, "Mental Events," in L. Foster and J. W. Swanson, eds. Experience and Theory (Amherst: University of Massachusetts Press, 1970),
,
Richard Rorty, "Mind-Body, Identity, Privacy, and Categories," in Review of Metaphysics (vol. 19, 1965, pp. 37-38); and Nagel's own "Physicalism," in Philosophical Review (vol. 74, 1965, pp. 339-356).
Nagel has extended his imaginative work on subjectivity in "The Limits of Objectivity," three lectures published in The Tanner Lectures on Human Values (New York: Cambridge University Press, and Salt Lake City: University of Utah Press, 1980), edited by Sterling McMurrin. Other imaginative work on the topic includes Adam Morton's Frames of Mind (New York: Oxford University Press, 1980) and Zeno Vendler's "Thinking of Individuals," in Nous (1976, pp. 35-46).
The questions raised by Nagel have been explored in many recent works. Some of the best discussion is reprinted in Ned Block's twovolume anthology, Readings in Philosophy of Psychology (Cambridge, Mass.:


Further Reading 479
Harvard University Press, 1980, 1981), along with many other articles and chapters on the topics encountered in The Mind's I. For some fascinating thought experiments about how a different understanding of science might change what it is like to be us, see Paul Churchland's Scientific Realism and the Plasticity of Mind (New York: Cambridge University Press, 1979).
A careful discussion of the mirror problem is Ned Block's "SrwoU\qU JoI4 bru 1391\tdBiA 9z-i9v9A zoo-niM oU ydW" in the Jour
nal of Philosophy (1974, pp. 259-277).
The perception of color, which Smullyan exploits in "An Epistemological Nightmare," has often been discussed by philosophers in the guise of the inverted spectrum thought experiment, which is at least as old as John Locke's Essay Concerning Human Understanding (1690, book 2, chap. 32, par. 15). How do I know that I see what you see (in the way of color) when we both look at a clear "blue" sky? We both learned the word "blue" by being shown things like clear skies, so our color-term use will be the same, even if what we see is different! For recent work on this ancient conundrum, see Block's anthology, and Paul and Patricia Churchland's "Functionalism, Qualia, and Intentionality," in Philosophical Topics
(vol. 12, no.1, spring 1981). Stranger than Fiction
The fantasies and thought experiments in this book are designed to make one think about the hard-to-reach corners of our concepts, but sometimes perfectly real phenomena are strange enough to shock us into a new perspective on ourselves. The facts about some of these strange cases are still hotly disputed, so one should read these apparently straightforward factual accounts with a healthy helping of skepticism.
Cases of multiple personalities-two or more persons "inhabiting" one body for alternating periods of time-have been made famous in two popular books, The Three Faces of Eve (New York: McGraw-Hill, 1957), by Corbett H. Thigpen and Hervey M. Cleckley, and Sybil (Warner paperbacks, 1973), by Flora Rheta Schreiber. Both books have been made into motion pictures. It should be apparent that nothing in the theories sketched or implied by the fantasies and reflections in this book would rule out multiple personality as impossible. Still, it may be that the recorded cases, however scrupulously described in the literature, have been too much the products of their observers' theoretical expectations, rather
Part VI. The Inner Eye

than phenomena that had a crisp and well-defined existence before being studied.
Every experimentalist knows the insidious dangers of the inherent
and inescapable bias with which a curious scientist faces the phenomena
to be studied. We usually know what we hope to discover (for we usually
know what our pet theory predicts), and unless we take great pains to
prevent it, that hope may fool our eyes and ears, or lead us to lay down
a subtle trail of hints to our subjects about what we expect from them
without us or our subjects realizing it. Laundering these "demand charac
teristics" out of experiments and using "double-blind" techniques of experimentation (where neither the subject nor the experimenter knows, at the time, which condition-test or control-is in effect) takes care and effort, and requires a highly artificial and constrained environment. Clinicians-psychoanalysts and doctors-exploring the strange and often tragic afflictions of their patients simply cannot and must not try to conduct their dealings with their patients under such strict laboratory conditions. Thus it is very likely that much of what has been honestly and conscientiously reported by clinicians is due not just to wishful thinking, but to wishful seeing and hearing, and to the Clever Hans effect. Clever Hans was a horse who astonished people in turn-of-the-century. Berlin with his apparent ability to do arithmetic. Asked for the sum of four and seven, for instance, Hans would stamp a hoof eleven times and stopwith no apparent coaching from his master, and with success over a wide variety of problems. After exhaustive testing, skeptical observers determined that Hans was being cued to stop stamping by a virtually imperceptible (and quite possibly entirely innocent and unintended) intake of breath by his trainer when Hans arrived at the correct number. The Clever Hans effect has been proven to occur in many psychological experiments with human beings (a faint smile on the experimenter's face tells the subjects they're on the right track, for instance, though they don't realize why they think so, and the experimenter doesn't realize he's smiling).
Clinical marvels such as Eve and Sybil, then, 6ught to be studied under laboratory conditions before we embark on serious efforts to accommodate our theories to them, but in general that has not proven to be in the best interests of the patients. There was, however, at least one striking study of Eve's dissociated personality, a partially "blind" study of her-their?-verbal associations, by a method that revealed three very different "semantic differentials" for Eve White, Eve Black, and Jane (the apparently fused person at the close of therapy). This is reported in C. E. Osgood, G. J. Suci, and P. H. Tannenbaum's The Measurement of Meaning (Champaign: University of Illinois Press, 1957). A recent report of a


Further Reading 481
newly discovered apparent case of multiple personality is Deborah Winer's "Anger and Dissociation: A Case Study of Multiple Personality," in the Journal of Abnormal Psychology (vol. 87, (3), 1978, pp. 368-372).
The famous split-brain subjects are another matter, for they have been investigated intensively and rigorously in laboratory settings for years. In certain forms of epilepsy a suggested treatment is a commissurotomy, an operation that almost cuts the brain in half-producing a left brain and a right brain that are almost independent. Amazing phenomena result-often strongly suggestive of the interpretation that commissurotomy splits the person or se V, in two. The huge literature that has sprung up in recent years about the split-brain subjects and the implications of their cases is lucidly and carefully discussed in Michael Gazzaniga's The Bisected Brain (New York: Appleton-Century-Crofts, 1970); in Michael Gazzaniga and Joseph Ledoux's The Integrated Mind (New York: Plenum, 1978); and by a well-informed philosopher, Charles Marks, in Commissurotomy, Consciousness and the Unity of Mind (Montgomery, Vt.: Bradford Books, 1979). Thomas Nagel has written one of the most provocative articles on the topic, "Brain Bisection and the Unity of Consciousness," which first appeared in Synthese (1971) and is reprinted in his Mortal Questions (New York: Cambridge University Press, 1979) along with "What Is It Like to Be a Bat?" and many other compelling essays, including several on topics raised by The Mind's I.
Another well-documented case that has recently interested philoso
phers and psychologists is that of a man who, due to brain damage, is
blind in a portion of his visual field. He claims (not surprisingly) that he
cannot see or experience anything in that portion of his visual field but
(surprisingly) he can "guess" with excellent reliability the shape and
orientation of certain symbols placed in his (rather large) "blind" area.
This has come to be called "blind sight," and it is reported in L. Weis
krantz, E. K. Warrington, M. D. Saunders, and J. Marshall, "Visual Capac
ity in the Hemianopic Field Following a Restricted Occipital Ablation,"
in Brain (vol. 97, 1974, pp. 709-728).
Howard Gardner's The Shattered Mind: The Patient After Brain Damage,
(New York: Knopf, 1974) is a highly readable and carefully researched
survey of other remarkable phenomena, and contains an excellent bibli
ography.
Classical accounts of particular individuals who should be familiar to
anyone seriously embarking on an attempt to theorize about conscious
ness and the self are to be found in two books by the great Soviet
psychologist A. R. Luria: The Mind of a Mnemonist (New York: Basic Books,
1968), the story of a man with an abnormally vivid and compendious
memory, and The Man with a Shattered World (New York: Basic Books,

1972), a harrowing and fascinating account of a man who suffered extensive brain damage in World War II, but who struggled heroically for years to put his mind back together and even managed to write an autobiographical account of what it was like to be him-probably as strange as anything a literate bat could tell us.
Helen Keller, who lost her sight and hearing when she was less than two years old, wrote several books that not only are moving documents but are full of fascinating observations for the theorist. The Story of My Life (New York: Doubleday, 1903, reprinted in 1954 with an introductory essay by Ralph Barton Perry) and The World I Live In (Century, 1908) give her version of what it was like to be her.
In Awakenings (New York: Doubleday, 1974) Oliver Sacks describes the histories of some real twentieth-century Rip Van Winkles or Sleeping Beauties, who in 1919 fell into profound sleeplike states as a result of an encephalitis epidemic and who in the mid-1960s were "awakened" by the administration of the new drug L-Dopa-with both wonderful and terrible results.
Another strange case is to be found in The Three Christs of Ypsilanti (New York: Knopf, 1964) by Milton Rokeach, which tells the true story of three inmates in a mental institution in Ypsilanti, Michigan, each of whom proclaimed himself to be Jesus Christ. They were introduced to each other, with interesting results.

This list of books and articles would be obsolete before anyone could read them all, and following up all the citations would soon turn into a life of scholarship in cognitive science and related fields. This is then a gateway into a garden of forking paths where you are free, happily, to choose your own trajectory, looping back when necessary, and even forward in time into the literature on these topics that is still to be written.

D.C.D. D.R.H.

ACKNOWLEDGMENTS

Cover: Magritte, Ren6, The False Mirror. (1928). Oil on canvas, 21 x 31/S". Collection, The Museum of Modern Art, New York. Purchase. Pages 35, 37, and 40 illustrations by Victor Juhasz. Page 45 illustration reprinted from The ManyWorlds of Interpretation of Quantum Mechanics, edited by Bryce S. DeWitt and Neill Graham (Princeton: Princeton University Press, 1973), p. 156. Page 48 illustration by Rick Granger. Pages 148, 157, and 175 lithographs and woodcuts of M. C. Escher are reproduced by permission of the Escher Foundation, Haags Gemeentemuseum, The Hague; copyright © the Escher Foundation, 1981; reproduction rights arranged courtesy of the Vorpal Galleries: New York, Chicago, San Francisco, and Laguna Beach. Page 189 illustration courtesy of C. W. Rettenmeyer. Pages 278 and 279 illustrations from Vicious Circles and Infinity: A Panoply of Paradoxes, by Patrick Hughes and George Brecht (New York: Doubleday, 1975). Page 349 illustration by John Tenniel from Alice in Wonderland and Through the Looking Glass (New York: Grosset & Dunlap, 1946), copyright © by Grosset & Dunlap. Page 405 illustration by Jim Hull.

In addition to the credit line appearing on the first page of each selection, the following publishers are also acknowledged for having given permission to reprint selections in Britain and the British Commonwealth countries: selections 6, 18, and 19 are reprinted courtesy of Martin Secker Sc Warburg Limited; selections 7 and 8 are reprinted courtesy of the author and the author's agents, Scott Meredith Literary Agency, Inc., 845 Third Avenue, New York, New York 10022.

Excerpt from "Why Can't He Be You" by Hank Cochran is reprinted courtesy of Tree Publishers, Inc.