Sentience

SENTIENCE

SENTIENCE

by WALLACE I. MATSON

UNIVERSITY OF CALIFORNIA PRESS

BERKELEY LOS ANGELES LONDON

University of California

Berkeley and Los Angeles, California

University of California Press, Ltd.

London, England

Copyright © 1976, by

The Regents of the University of California

ISBN 0-520-09538-3

Library of Congress Catalog Card Number: 75-3774

Printed in the United States of America

TO

William Ray Dennes

Contents

Contents

Acknowledgments

I PROBLEMS

II IDENTITY

III PRIVACY

IV MACHINES

V SENTIENCE

VI FREEDOM

Index

Acknowledgments

To the National Endowment for the Humanities for unbureaucratically administered support of this project.

To Renford Bambrough, the Master and Fellows of St. John’s College, and the many other friends in Cambridge who provided agreeable compensations for the agonies of composition.

To the Humanities Research Committee of the University of California for leisure to write the last chapter.

To Fred K. Beeson II and Charles Jarrett for acute, patient, thorough and constructive discussions of the work from conception to completion. Moreover, in Charles I found a research assistant on whose judicious assessment of the literature I could rely absolutely.

To Rick Doepke, William Gean, and Gonzalo Munévar for helpful comments on various drafts.

To Hubert Dreyfus, who first interrupted my analytic slumber.

To Bruce Vermazen, who gently restrained me from putting concepts into orbit.

To Warrington Colescott for Figure 1.

To Gene Thompson for the joke discussed in Chapter 5.

To Savannah Ross, Katy Dreith, Julie Martinson, and Yulia Motofuji, who were so nice about the typing.

To my wife, on general principles.

Finally, to Benedictus de Spinoza, who I believe had the truest conception of man.

I

PROBLEMS

Man said Democritus is what we all know about.

¹ Strange words to come from the father of materialism, a philosophy that might be self-evidently true if only there were no people.

In a way, we do know about man: We are men, so we know what it is to be men, as cats know what it is to be cats. We know what we do, how we do it, and why, at least sometimes. Wanting this or that, we size up our situation, devise our plans, and act accordingly. This pattern and its endless variants are indeed so familiar that the natural human tendency is to deem anything at all explained just insofar as it has been comprehended in these terms. Hence the religious world view.

We have the advantage over cats of being able to reflect articulately on our selves and our doings, to conceptualize ourselves. It is an advantage, for it can lead to knowledge even though theories are more likely to be wrong than right. Theories about man tend to split him into two parts, a grosser and a subtler. The most naive of these dualisms is a simple application of anthropomorphic explanation to man himself. In keeping with the general tendency to explain happenings by postulating a manlike agent, a man’s behavior is theorized to be due to a little man inside manipulating the grosser limbs, tongue, etc. We smile at the ka oí the Egyptians, but as we shall have occasion to note hereafter, rus progeny are not extinct.

Under the influence of meditations on the difference between the foreman or king, who sits and gives orders, and the slave who need not think but only do his bidding, the model of man is refined into a ruling part, which does the planning and issues the orders, and the visible body, which is mere apparatus for carrying out directives—but alas, like slaves and subordinates generally, is apt to be sullen, lazy, rebellious, and the enemy of reason. Division and opposition are carried to the point where the ruling element is indeed thought of as completely separate from the body and alien to it, imprisoned in it as punishment for sin but to be freed on some glorious day.

In this kind of dualism, sentience is counted on the bodily side. It is too obvious that we see with our eyes and taste with our tongues for the sense functions to be dreamed of as divorced from the flesh. Ancient speculation grapples, in vain, with the question of how the eye sees, more successfully with how the ear hears; but it does not at all perceive as a problem how it can be that any material structure can have sensations. In terms of current controversy, all the ancients must be counted as identity theorists: they held, or at any rate took for granted, that sensations, including pains, were bodily processes throughout. Only the intellect—judgment, abstract reasoning, whatever it is that we are intelligent and virtuous with—was identified with that separable ruling element.

²

Nevertheless, presages of the problems of later times are to be found in the earliest materialism. When the personal model for explanation is rejected uncompromisingly, as it is by Democritus, and in its place is put the model of causal interaction of material particles, the question leaps to prominence: What is to be done about the actual, undeniable manifestations of sentience in ourselves? If there is nothing, really, but atoms hitting one another in the void, then that is all we are, really. How are we to understand these collisions as aches and pains, colors and tastes? Democritus seems to have been on to an explanation of the right type when he tried to account for tastes in terms of atomic shape; I say right type because he explained (for example) not sour taste but the (event of) vinegar’s tasting sour; it was due, he said, to the spiky shape of the vinegar atom—that is, the disposition of that atom to prickle the tongue.

³ However, this still leaves us with the unanswered—indeed, for Democritus unasked—question why prickling the tongue should be felt at all.

Generally, and I think rightly, Descartes is credited with having invented the mind-body problem as we know it. He did this by beginning his philosophy not with a fund of common knowledge about the world and man but with what we can be absolutely certain of, which in his opinion is only the existence of the thinking self. This means that everything whose being is exhausted in my present awareness is to be put in one bin, distinguished from those items, in a second bin, that could fail to exist, at least conceivably, without altering my consciousness. The first bin, then, contains all my thoughts, feelings, aches, pains, and sensations—put now on the side of the mind, contrary to ancient practice, and contrasted with the physical which includes my body, but only as a thing in itself insentient. Thus, there are two kinds of things: mental things and physical things. The one kind can exist and be just what it is without the other (as dreams are supposed to show), and indeed the major problem bequeathed to the new philosophy is how there can be conceived to be any intercourse between them at all.

It has come about, I know not how, that this division and the problems it engenders seem natural and uncontrived to people otherwise not much inclined to give credence to the extravagances of metaphysics. For example, half a century ago E. D. Adrian (later Lord Adrian and Nobel laureate), expressed a typical puzzlement at the beginning of his book on The Basis of Sensation:

⁴

The final chapter deals briefly and timidly with the relation between the message in the sensory nerve and the sensation aroused in our consciousness; briefly because the relation is simple enough in a way, and timidly because the whole problem of the connection between the brain and the mind is as puzzling to the physiologist as it is to the philosopher. Perhaps some drastic revision of our systems of knowledge will explain how a pattern of nervous impulses can cause a thought, or show that the two events are really the same thing looked at from a different point of view. If such a revision is made, I can only hope that I may be able to understand it.

My aim in this book is to persuade you that the two events are indeed really the same thing—to return us, so to speak, to archaic innocence in our view of man, but without jettisoning whatever sophistication we may have picked up along the way. That is, I want to present a conceptualized identity theory of mind and body.

I am not alone in having this goal, which was never lost sight of entirely: No less a philosopher than Aristotle pursued it in antiquity, while as for the heroic age of modern thought, if only people would read their Spinoza, there would be little need to say anything further. In our own day, dualist views have recently gone so out of fashion that I shall not pause to criticize them here.⁵ And anyone writing after Ryle can hardly hope to do more than tidy up.

In carrying out this humble though, I hope, useful task I shall assume that a living man is a certain quantity of matter, a selection out of the ninety-two natural elements, combined in a complicated organization that functions as a unity in growth, nourishment, reproduction, and action. He lives for a time; sooner or later the unitary functioning ceases. When it does, that is the end of the man; what is left over is functionless matter which unless artificially preserved soon undergoes chemical decomposition and merges into the relatively undifferentiated reservoir of organic stuff—the dust. This view does not deny that a man has a mind or, if you prefer, a soul; it does deny, however, that mind or soul is a name for anything other than an aspect of the workings of the body.

This view is really a framework thesis, not a detailed theory, so most of the discussion can be carried on in terms of a simple, sloganlike statement:

Sensations are necessarily brain processes.

Or somewhat more exactly,

It is possible that sensations are brain processes; and if sensations are brain processes, then sensations are necessarily brain processes.

Except for modality, this thesis is the same as the contingent identity theory associated especially with Place, Smart, and Armstrong. Thus much of the work of showing its internal consistency is something that need not be done over again. The discussion can concentrate on the question of the modality in which I want to express the thesis: the claim, that is, that if sensations are brain processes then they cannot be, could not be, could not have been, anything else. This is the hard materialist line. It is traditional and also, it seems, hard to swallow, inasmuch as the resurgence of materialistic philosophy of mind seems to be due to its having been softened into the contingency view.

To many readers, especially perhaps those whose interests are more in psychology than philosophy, the question of the modality in which the identity theory is to be expressed will be of little concern. I hope they will not put the book down but will simply skip Chapter II. I have felt it necessary to include that chapter, however, for three reasons. First, I think the contingent identity theory is false, because it rests on a wrong theory of language. Second, if the contingent identity theory is true, there can be no reason to believe that it is true. For that theory is to the effect that while as a matter of fact sensations in this world are nothing but brain processes, there could be worlds in which sensations had no sort of connection with brain processes (or heart or liver processes for that matter). But if so, there can be really no way of telling that this world is not one of those worlds. It is not, nor could it be, a scientific discovery that sensations are identical with brain processes as a matter of fact, and as opposed to being ontologically different occurrences merely correlated with them.⁶ The third reason will appear when in the final chapter it is shown that the defense of freedom against objections based on determinism depends crucially on there being a necessary identity.

After this part of the argument, the remainder of the book will be concerned with answering the broad questions What is sentience? Why is there any such phenomenon? What difference does it make? These vague questions will be sharpened up when the time comes to do so. My aim is to steer a materialist theory of mind along the strait and narrow path between two bogs, on the one hand epiphenomenalism, the view that everything would go on just as it does even if there were no consciousness in the world; on the other, (Watsonian) behaviorism, the paradoxical denial that there really is any such thing as consciousness.

In the third chapter I shall try to show that sentience is not to be conceptualized as a privileged view of a set of private objects. The conclusion is hardly new, but perhaps some of my reasons supplement and strengthen those urged by others. Chapter IV is intended to relieve the anxiety of those who fear that if the mind is identified with the brain, then man is nothing but a machine, to wit, a digital computer. Here I rely heavily on the thought of my colleague Hubert Dreyfus. Having said what man is not, I try in the succeeding chapter to say what he is: to face the naive-sounding but I believe valid and important question, What is the use of sentience? What can a sentient being do that a nonsentient being could not do?

Lastly, I shall try to succeed where Epicurus failed and give a satisfactory materialist account of free will— one that does not merely reassure us that we are free as water is free to run downhill.

I think that what I am doing in this book is properly to be called philosophy, though I could face with equanimity an official ruling that it is not. But perhaps some apology ought to be made for dealing with questions that at least closely border on physiology and empirical psychology, subjects in which I claim no competence. Fortunately, the whole topic of sentience divides itself rather sharply into two parts. The neurophysiologist certainly does not wait to hear from the philosopher before proceeding on whatever line of investigation he is interested in. Nor should he. If he is, say, looking into the mode of action of the receptors for the sense of smell, all his concern is with what goes on when effluvia from a rose enter the nostrils arid make contact with the specialized cells embedded therein. If he can give a satisfactory account of the energizing of the whole path from nostril to olfactory cortex, he has done his job. That is what smelling is, he is entitled to say. He will have discovered that when such-and-such events go on in the brain, such and such olfactory sensations are experienced. The question whether the olfactory sensation is the same as the neural excitation, or a ghostly accompaniment, is one in which the physiologist no doubt will have an interest, but not a professional interest. There is nothing he can do with his ingenious apparatus and techniques to resolve it.

The philosopher, on his side, who is interested in resolving this kind of question, need not know anything about the physiological details, as long as he knows that what occurred was the transmission of a message from a point on the nervous periphery to a region more centrally located. We know now that the transmission is electrochemical. Descartes thought it was hydraulic; Aristotle didn’t think it happened in the brain at all, but in the heart. None of this bears on the philosopher’s task, which is that of trying to make sense of the very notion of a relation between what initially impress us as being such different affairs that they could hardly have anything in common: the propagated physical change, on the one hand; the feeling, on the other. The philosopher’s job will be finished when he can rightly claim to have given an intellectually satisfying account of the structure of a whole, which includes both the brain events and the feelings and which either leaves no gaps between them or, if it does, makes it clear why there must be gaps.

1 Fragment 165 (Diels).

2 For a fuller account see my paper Why Isn’t the Mind-Body Problem Ancient? in Paul K. Feyerabend and Grover Maxwell, ed., Mind, Matter, and Method (Minneapolis: University of Minnesota Press, 1966).

3 See Theophrastus, De Sensu, 65.

4 (London: Christophers, 1928).

5 Anyone requiring argumentation may turn to Lucretius, Book m, 450—850, whose twenty-odd arguments are still cumulatively conclusive.

6 Indeed, there is something unconvincing about the insistence of the contingentists that Sensations are brain processes is a scientific discovery. Who made it? When? How? There may be answers to these questions—though it is doubtful if anyone knows what they are—if the sentence is understood as filled out with and not heart or liver processes, as we formerly believed. But that is neither here nor there in the philosophical controversy.

II

IDENTITY

I shall discuss the identity theory of mind and brain in the form that has become, as it were, canonical:

Sensations are brain processes.

This perhaps does not look like much in the way of a theory, and