THE TIMES HIGHER MAY 19 1995 T h e Mind-Body Problem contains recent essays by the key players i n the field: Searle, Fodor, Honderich, Nagel, McGinn, Stich, Rorty and others. But there are a few interesting exceptions, f o r example Edelman, Popper, Putnam and Dennett. Nevertheless, these thinkers do get a mention here and there, and nearly all the exciting topical issues are dealt with, including externalism, functionalism, intentionality, Tur ing computational models, and the relationship between these philosophical problems and psychology. The writers fall into three broad and vague categories: those who espouse a confident promissory physicalism; those w h o bold ly assert the non-reducibility of the mental; and those who think the terms of the debate are unclear or have other reservations about making any speculative leaps. On the physicalist side there are Lewis, Smart, Fodor, the Churchlands and Shoemaker. With the aid of a Coke-dispensing machine, Fodor contrasts logical behaviourism (which reduces the mental to input and output) and internal state functionalism (which includes internal processing and accounts for the interdetinability of mental states). As a counter to functionalism, Honderich provides a powerful defence of the existence of a mental content over and above any functionalist causal relations and introduces his Union theory. I am particularly struck by the tendency to engage in an evasive stratagem when it comes to stating the physicalist thesis. Instead of a clear definitive position about what k ind o f physical science W h a t is happening in the B Y RICHARD COOPERhuman head to produce• • , BOOKS PSYCHOLOGY Worlds 3 Popper 0 BY RAY S. PERCIVAL THE MIND-BODY PROBLEM: A GUIDE TO THE CURRENT DEBATE EDITED BY RICHARD WARNER AND TADEUSZ SZUBKA 407pp, E45.00 and 614.99 ISBN 0 631 19065 6 and 19086 4 would achieve t h e hoped-for reduction, what I found was variations on Lewis's claim that the reduction would be effected by a "unified body of scientific theories of the sort we now accept". Materialism used to be a clear doctrine: a clockwork Universe of impenetrable particles. But materialism transcended itself. F i r t through Newton's demolition of the Cartesian idea that matter was essentially extension b y introducing gravity (action at a distance) and then through the field iheories of Faraday and Maxwell, and more recently through Einstein's work, which undermined t h e " sub stance" view of matter, something that remained permanent while other changes occurred. John Wheeler o n c e s a i d "par t ic le physics is not the right starting point for particle physics. Vacuum physics is". "Matter" is more accurately seen as a process that is one form of energy, and the physical world is now conceived as an interaction of processes rather than of things - talk of particles is shorthand. The trouble with Lewis's phrase "of the sort we now accept", perspicuously focused on by the editors, is that i t is open to endless shift as science progresses. Whatever new explanatory theories and concepts are developed, the physicalist can just call these "physical". The Churchlands are very confident about a future physicalist reduction of the mental and their discussion of the reduction of temperature t o molecular kinet ic energy is helpful as a paradigm. However, they neglect to point out that this reduction is incomplete. It fails to account for the temperature of plasma, which consists of disintegrated atoms, a n d t h e behaviour of a system of particles is subject t o what Donald T. Campbell calls "downward causation" - the structure of a star, for example, constrains the behaviour and even type of the constituent particles. The Churchlands also portray Newton's theory as a reduction of Kepler's laws, but, as first noted b y Duhem (1906), Kepler's laws contradict Newton's theory because they assume that the planets do not interact. Popper (1972) pointed out that Kepler's laws can be derived from Newton's theory only i f one assumes the planets have either equal or zero mass and also injects into Kepler's theory the post-Keplertan notion o f gravity - that is, only by denying Newton's and Kepler's theories. Getting your ACT together learning, and i n such circumstances a change in attitude will Some o f those who express reservations about the possibility of a physical explanation or reduction reveal a misapprehension about the logic of debate. Nagel suggests that in the absence of a detailed physical reduction, one should not speculate either positively or negatively. But it is only speculation (plus refutation) that will take us beyond the known. Of particular interest for psychologists is Stich's discussion of experimental studies o f concept formation and use that show that people ordinarily do not construct concepts from necessary and sufficient conditions, but instead use protoiypical cases or make up concepts according to the problem in hand. These facts. Stich says, undermine the traditional Socratic method o f conceptual analysis, and indicate that there are no classical concepts. However, one can simply stipulate a concept by a set of necessary and sufficient conditions, as is done in science. Searle is as bold as ever, and he gives a good argument that the terms of the debate are misleading. The following, Searle says, are not easily categorised in to mental or physical: balance-of-payments problems, ungrammatical s e n tences, reasons for being suspicious of modal logic, my ability to ski and points scored in football games. Although a good snapshot of the mind-body debate I got the impression that insufficient anew. 31 tion is paid to the explanatory potential of the evolutionary perspective, a perspective developed by, among others, Dennett, Edelman, Campbell, Popper a n d Eccles. A n important breakthrough here would be to show how abstract theories and arguments, as opposed to concepts, can evolve from rudimentary advantageous "fitting" o r "matching" of biology and world. Moreover, given the testable versions of emergentism by Stuart Kaufman and others, i t i s dismissed too easily. Also neglected is Popper's tripartite ontological division of the world into the three domains: world 1 (the world o f physics), world 2 (the world of psychological states and dispositions) and world 3 (the world of objective theories and other abstract products of the human mind). It is not obvious, as Galen Strawson suggests, that one is a materialist simply by positing non-experiential phenomena. Each of the items in Searle's heterogeneous l i s t could be accurately analysed in terms of these three domains. A score in a football game, for example, can be analysed, as a first step, into the physical marks or electronic states that code the score (world 1), the number understood as an abstract object with properties independent of its coding and the logical ramifications o f this score for the game (world 3), and the psychological grasping of the score and its logical ramifications for the game and the individual player (world 2). Ray Percival is organiser o f an annual conference on the philosophy of Karl Popper.