Preface In the mid -seventies I discovered that my patience with most main - stream philosophy had run out . What had instead begun to seem promising was the new wave in philosophical method , which ceased to pander to " ordinary language" and which began in earnest to reverse the antiscientific bias typical of " linguistic analysis." Even here I had a major misgiving , however , because the sciences em - braced by the new wave as relevant to understanding the nature of the mind did not include neuroscience . Indeed , the best of what there was had espoused a novel and sophisticated form of dualism - theory dualism - that dismissed neuroscience as largely irrelevant to theo- ries in psychology and philosophy . Since I was a materialist and hence believed that the mind is the brain , it seemed obvious that a wider understanding of neuroscience could not fail to be useful if I wanted to know how we see , how we think and reason and decide . I therefore decided to find out in detail whether what was already known in neuroscience was of any use in understanding cognitive functions . Beginning with ..a cautious paddling at the available edges of neuroscience , I quickly found myself venturing further and further from shore, and finally setting tull sail. In the midst of the unencumbered delights of discovering what was known about nervous systems and how neurobiologists got that knowledge , questions of a distinctly philosophical nature continued to make demanding background noises: Is it possible that we could have one grand , unified theory of the mind -brain ? What would such a theory look like ? Is a reductionist strategy reasonable or not ? As a philosopher , I had found myself driven to the neurosciences, but having immersed myself in the neurosciences, I found I could not leave the philosophy alone either . For those far-reaching, wide - embracing questions asked about neuroscientific research I well rec- ognized to be philosophical questions- moreover, questions where philosophers of science and historians of science have had useful things to say. It is now evident that where one discipline ends and the other begins no longer matters, for it is in the nature of the case that x Preface the boundaries are ill defined . This book is thus the result of what I came to regard as neurophilosophicalinquiries. Given the range of topics I needed to know about, I was through - out the project necessarily dependent on the willingness of neuro- scientists to explain their research, to tell me what they thought was important and why , and to give advice on who else to talk to and what to read. My vvorst fear- that as a philosopher I would be con- sidered an utter waste of time- was virtually never realized. Invari - ably neuroscientists were exceedingly generous, often going beyond explanations asked, allowing me to observe or participate in experi- ments, explaining details of techniques, and drawing back the curtain on the wider vision that motivated their research. From time to time I found considerable disagreement among neuroscientists on fundamental issues, and at first I tacitly assumed that there must be someone who really knew what was what and who could settle for me what is the Truth . In the end I knew that I had to make up my own mind , and do it the way any neuroscientist would : find out as much as I reasonably could about the issue and go with what seemed most reasonable. A vague decision procedure, to be sure, but the only one I know of. Without the generosity and patience of many people, not only neuroscientists, but also philosophers , psychologists, and computer scientists, this book would still be a shapeless intention . To Larry Jordan I am especially indebted for giving me a basis in neurophysiol - ogy and in laboratory techniques and for convincing me that it is essential to think about how organisms move. I also owe an enor- mous debt to Rodolfo Llinas, whose unique blend of experimental understanding and drive for theory gave me a sense of what a large, unifying framework for neurobiology and psychology might look like and how known data would figure in that framework . For similar reasons, I am grateful to Francis Crick, whose general understanding of the entire field of vision and sense of how theoretical problems in neurobiology might be solved directed me in getting a grip on the functional questions . More than anyone else, Llinas and Crick have made neuroscience seem like the most exciting thing in the world and consequently rekindled - and, I suspect, realigned- my philosoph - ical preoccupations . Among philosophers , my first and greatest debt is to Paul M . Churchland , who has been a partner in the venture from the very beginning . It was he especially who convinced me of the importance of bringing science and the philosophy of science to bear on questions in the philosophy of mind , and this has made all the difference in thinking about consciousness, cognition , and subjective experience, and about the general framework needed for a unified science of the . Preface Xl mind -brain . Consistently naturalistic in his approach to philosophical questions, and robustly skeptical of folk psychology, he pointed me in the direction of the neurosciences. Dan Dennett made a difference in countless ~ ays, one of which was convincing me to write the book in the first place. In addition , by taking a blue pencil to the manu- script in several of its incarnations , he helped me avoid many mis- takes. Best of all, perhaps, he set an example of how philosophy ought to be done. Stephen Stich also gave me unstinting encourage- ment and advice, and his ruthless clarity helped keep mushiness from creeping in . To Jerry Feldman I owe a debt of thanks for a careful reading of the manuscript and for much useful criticism and advice. Cliff Hooker discussed large parts of the manuscript with me as well, and his general conception of the development of philosophy since the turn of the century provided an organizing focus. Many other people gave me ideas, advice, and invaluable conversa- tion or read some substantial section of the manuscript and suggested revisions . I should mention especially the following : Ted Bullock, Jeff Foss, Don Griffin , Alastair Hannay , Stevan Hamad , Ken Heilman , Don Herzog, Geoffrey Hinton , Marcel Kinsbourne , Marta Kutas, Michael Gazzaniga, Ron Giere, Lisa Lloyd , Vemon Mountcastle , David alton , Andras Pellionisz, Susan Schefchyk, Martin Sereno, Terry Sejnowski, Allison Shalinsky, Aaron Smith, Michael Stack, Larry Weiskrantz , Chris Wood, David Zipser, and Steve Zucker . I want also to thank Harry and Betty Stanton of MIT Press/Bradford Books for their genteel encouragement and for making the produc - tion end of publication almost fun . Gustav Szabo designed the cover, and I am grateful to him for .working out exactly the right theme. Finally , thanks to Darlene Stack for the ready supply of buck-you- uppo and for entertaining us through many a Manitoba blizzard . For financial support , my greatest debt is to the Social Sciencesand Humanities Research Council of Canada, without whose generous funding in providing release time from teaching this project would have been impossible (grants 410- 81- 0182, 451- 83- 3049). I am also grateful to the University of California at San Diego for support in the final stages of preparation of the manuscript (grants RJ111-G, RK91- G). In addition , I should like to thank the Institute for Advanced Study in Princeton for giving me a peaceful and productive year in 1982-1983, during which large portions of the book moved into posi- tion . I owe a special debt to the University of Manitoba for having the courage to support me in a host of important ways on a project that was not, by most lights , conventional . PSC La Jolla1985 N europhilosophy One ought to know that on the one hand pleasure, joy , laughter, and games, and on the other, grief , sorrow, discontent, and dissatisfaction arise only from the brain . It is especially by it that we think , comprehend, see, and hear, that we distinfl,uish the ugly from the beautiful , the bad from the good, the agreeablefrom the disagreeable. Hi ppocra tes Philosophyis like the mother who gave birth to and endowedall the other sciences. Therefore, one should not scorn her in her nakednessand poverty, but should hope, rather! that part of her Don Quixote ideal will live on in her children so that they do not sink into philistinism. Albert Einstein , 1932 GeneralIntroduction Squirming out from the primordial ooze, our evolutionary ancestors harbored within themselves a perfectly astounding invention - the excitable cell. Such is a cell that can pass a tiny electrical effect down its extent and that, in concert with clumps and configurations of similarly excitable cells, can be appropriately excited so that the or- ganism may move, thereby feeding, fleeing, fighting , or reproducing . From the very beginning , mobile creatures whose excitable cells were capable of conveying information about conditions outside the body had a survival advantage over those whose movements were inde- pendent of whatever was going on outside . Obviously , the organism that flees in the absence of predators and feeds willy -nilly is doomed to be prey for those more lucky organisms fitted out with cells coor- dinating representationsof the world with movementin the world. With increased complexity of behavioral repertoire comes increased capac- ity for representing the environment . Our own brains are massive mounds of excitable cells, which some- how contrive collectively to contain a rich representation of the out- side world , as well as to enable the muscles to accomplish such feats as catching a ball, playing the violin , and talking , in addition of course to the fundamental feeding, fleeing, fighting , and reproduc - ing .