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Mario Bunge, The Mind-Body Problem, a Psychobiological Approach, Pergamon Press, 1980; xvi + 250 pp.

The author's purpose in writing this comprehensive book is to "offer an examination of rival doctrines of mind as well as a general framework for building specific theories of mental abilities". Since the mind-body prob- lem is at present under intensive study, this goal is admirable. The current interest in the subject needs no justification, since (i) the problem of mind is a central philosophical issue, and (ii) recent advances in neurophysiology and technology have provided us with new ideas and methods for attack- ing the relevant sub-problems. Professor Bunge's book is thus a timely contribution to the intellectual scene.

The book's ten chapters divide neatly into two consecutive parts. The first three chapters contain a systematic review of various historically fa- miliar solutions, 1 as well as a philosophical and mathematical introduction to the author's preferred solution: emergentist materialism. Bunge's theses are presented in set-theoretical terms, by exploiting the apparatus of his ear- lier Treatise on Basic Philosophy, Volume 3 (Reidel, 1977-1979). Philoso- phers and scientists interested in emergentist ideas can profit from these three chapters, although the text is not free of conceptual and technical inaccuracies. I will discuss Bunge's emergentism below.

Chapters four through ten contain sketches for emergentist materialist descriptions of specific kinds of mental activity. Some possible biological bases of sensing, perceiving, learning, thinking, knowing, being conscious, and association are discussed in depth, with copious references to the scien- tific and philosophical literature. This part is intended to show that the program of the first part can in principle be fulfilled.

Erkenntnis 17 (1982) 399-403. 0165-0106/82/0173-0399 $00.50. Copyright �9 1982 by D. Reidel Publishing Co., Dordrecht,'Holland, and Boston, U.S.A.

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II

Bunge argues for his version of emergentism by contrasting it with some other popular 'solutions' to the mind-body problem. Idealism and various species of dualism are rejected as manifestly inadequate, ad hoc, or openly antiscientific (i.e. irrationalistic). For our purposes, the most interesting competitor to emergentist materialism is what Bunge calls 'physicalism' (p. 9). This view identifies each mental state with a sole physical state, and claims that mental states are in fact reducible to physical states (although reducibility-relations are not explored in detail). This is a version of the identity theory and is dubbed "reductive materialism". 2 It is rejected, on the grounds that "it does not square with the qualitative variety of real- i ty. . ." (p. 6). I take this to mean that even concepts from an optimal and definitive physical theory of inorganic nature cannot fully describe the cognitive, sentient, and conative activities of living organisms. It is claimed (p. 10) that only emergentist materialism can "account for the specificity of the mental" (my italics). No emergent properties, no mental life. In par- ticular, this view holds that nothing in a world devoid of emergent prop- erties can be sentient or conscious.

Suppose that not all brain properties (or properties of parts of brains) in which we are interested are items described by ideal physics. These properties, e.g. being conscious, are said to be emergent brain properties. They can 'emerge onto' a brain (or a part of a brain) only if that brain exhibits sufficient physical complexity, a Now the crucial point in Professor Bunge's strategy is this: the claim that there are emergent mental properties is scientifically respectable; for any emergent property characterizes only items in nature, and is systematically related to purely physical (non- mental) properties. Thus emergentism can be materialistic, and need not commit one (it is held) to antiscientific irrationalism or to dualism. 4

Let us examine this proposal. Let x be some organism. Then a property P such that P(x) is emergent (with respect to x)just in case no part o f x has P (p. 32). It is clear that this notion of Bunge's is too broad. For let 'x' denote the present reviewer. Then on this analysis being conscious and being a vertebrate organism are both emergent properties with respect to me. Thus Bungean emergentism does not capture the "specificity" of my mental life. The very strange fact that I am a part of nature that describes itself (accurately or not) as being conscious is not at all ontologically

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distinguished (on this treatment) from the following fact: that I am a vertebrate organism. More generally, some of my physico-biological prop- erties are Bunge-emergent with respect to me. Contrary to the author's desires, his definition of emergence suppresses precisely that peculiar men- talistic specificity which he is trying to capture.

There is at least one other basic problem with the general theory which devalues its contribution to the solution of the mind-body problem. 5 Sup- pose that Bunge accepts the above result. Suppose as well that he can explain why I am a vertabrate by reference to my skeletal, cellular, and genetic composition and structure. Nevertheless, he cannot (today) explain why I am conscious. We know too little about persons to do this. That is,

Bunge cannot e x p l a n a t o r i l y c o n n e c t - at present my being conscious with my having a given physico-biological constitution (e.g. via a deduc- tive nomological systematization). The isolated conjunctive claim that (i) I am an organism of physico-biological type p, and that (ii) anything of type p has a family F of emergent mental properties, is unilluminating. It renders me highly mysterious, since (ii) alone neither (a) displays the logi- cal form of this presumptive p - F correlation nor does it (b) explain why this correlation obtains. This claim is one that a solution to our problem should analyse in depth. This shows that emergentist materialism may be just as obscure as epiphenomenalism or vitalism. 6'7

I l l

Chapters 4-10 contain neurophysiological and system-theoretical ac- counts of notions such as detection, sensation, experience, learning, and thinking. Given our lack of detailed theories of brain operation, these ac- counts must be somewhat speculative. The author is aware of this, and no doubt feels that he is doing his best in a chaotic and incomplete scientific situation. All philosophies of mind are in the same condition of almost total ignorance. Professor Bunge's analyses are based upon D. Bindra's modification of D. O. Hebb's theory of cell assemblies. 8 They are stated within a general mathematical framework for describing things, events, and processes.

Despite this attempt at precision, conceptual problems remain. Let 'P ' stand for a monadic property which is held to be emergent and mental, and let 0 he the psychobiological statement with one free variable cor-

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related with 'P'. Then

( + ) Vx [P(x) ~ O(x)]

is typical of the form into which many of Bunge's definitions may be cast. Note that ( + ) is an explicit definition of 'P ' in psychobiological terms. There are now two possibilities:

~

2.

( + ) illustrates the acceptable form for emergentist-materialist claims; ( + ) allows 'P' to be eliminated from all extensional contexts.

The first option has been ruled out by the argument in II against emer- gentist materialism, so we are left with 2. But 2 turns ( + ) (and all relevant claims of the same form) into a reducibility thesis (or into a thesis of elim- inative materialism). For we can argue that if ( + ) holds, and if 2 is correct, then mental property P has been reduced to (or eliminated by) the neuro- physiological property expressed by 0. Hence chapters 4-10 propound a form of reductive materialism. This renders the text incoherent, since re- ductive materialism is rejected in chapters 1-3. 9

Due to the shortcomings here enumerated, the text must be read with caution and with a degree of skepticism. Nevertheless, its attempt at systematization, and its extensive concrete use of technical neurophysiol- ogical data and theories, enable one to read the book with profit.

Erasmus Universiteit, Rotterdam Nederland

G E O R G E B E R G E R

N O T E S

i This should be compared with C. D. Broad's classical survey in The Mind and its Place in Nature, Cambridge University Press, 1923. 2 The fundamental papers on the identity approach can be found in The Mind/Brain Identity Theory, edited by C. V. Borst, London, the Macmillan Press, 1970. 3 For a critical study of emergentism in various forms, see chapters 11 and 12 of Ernest Nagel's The Structure of Science, New York, Harcourt, Brace and World, 1961. 4 Cf. Paul Meehl and Wilfrid Sellars, 'The Concept of Emergence', in Minnesota Studies in the Philosophy of Science, Vol. 1, edited by Herbert Feigl and Michael Scriven, Minneapolis, University of Minnesota Press, 1956, pp. 239-252.

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For brevity ! write as if the mind-body problem were one problem. This is probably false. 6 Cf. Nagel, ibid. 7 Some progress has recently been made. See G. Hellman and F. Thompson, "Physicalism: Ontology, Determination, and Reduction', Journal of Philosophy 72 (1975), 551-564. 8 D. Bindra, A Theory of Intelligent Behavior, New York, John Wiley and Sons, 1976. 9 On reduction and emergence see R. L. Causey, UniO' of Science, Dordrecht, D. Reidel, 1977.

Manuscript received 20 January 1980