Philosophical Materialism Author(s): Colin McGinn Source: Synthese, Vol. 44, No. 2 (Jun., 1980), pp. 173-206 Published by: Springer Stable URL: http://www.jstor.org/stable/20115525 . Accessed: 26/03/2011 08:01 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at . http://www.jstor.org/action/showPublisher?publisherCode=springer. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. 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The objects thus referred to and quantified over make up the ontology of the original mental discourse. The predicates of the theory, on the other hand, will be interpreted as expressing properties attributed to the objects in the domain of the theory.2 The intuitive notion of the 'subject matter' of mental sentences is then to be understood in terms of such an assignment of objects and properties to terms and predicates of the regimented theory. Now consider a like regimentation of physical discourse relating to the body and brain, containing scientific vocalulary, extant and future. The ontology of this physical theory comprises organisms and physical events and - - states neural and behavioural let us suppose while its predicates are taken as attributing properties to such physical entities. Then, supposing all this, the question as to the relation between mind and body can be formulated in two parts: (a) what is the relation between the respective ontologies of the mental and physical theories? and (b) in what kind of relation do the properties ascribed by the theories stand? In this paper I shall offer some considerations in favour of the following answers to this pair of questions: mental objects are iden tical with (or are composed of) physical objects, and mental proper ties are neither nomologically reducible to physical properties nor (in a sense to be explained) lawfully correlated with them. This com posite thesis is familiar from the writings of Donald Davidson as anomalous monism;3 my supporting considerations will be less familiar. Before presenting these considerations, a word is in order on the epistemological status of these claims. It is commonly supposed, on the model of theoretical identification in science, that materialist Synthese 44 (1980) 173-206. 0039-7857/80/0442-0173 $03.40 Copyright ? 1980 by D. Reidel Publishing Co., Dordrecht, Holland, and Boston, U.S.A. 174 COLIN McGINN theses (and their negations) have the status of scientific hypotheses: they are to be decided by means of a posteriori procedures, specifically experimental investigations of a psycho-physiological sort.4 On that view acceptance or rejection of anomalous monism will perforce wait upon the prosecution of such researches; a philosopher can only distinguish the possible outcomes and indulge in more or less unfounded empirical speculation. The contrary view, which I wish to endorse, is that questions (a) and (b) admit of a priori resolution and fall therefore strictly within the province of the philosopher (hence my title). This difference of methodological view can be brought out as follows. Suppose that you have resolved, by the usual criteria, that a certain creature (or species of creature) is endowed with the psychological properties typical of a human person, and that you know the creature's complete mental description. But suppose also that you know next to nothing of the physical properties of the bodily organ which is 'responsible for' its mental activity: perhaps it is some species of extra-terrestrial person totally unlike us physically, or perhaps you are back in the days before the human sensorium was identified and investigated. Nevertheless, you are enough of a materialist to believe there to be such an organ and that there are causal and other relations between events in it and mental phenomena. You are, then, in a position to wonder how exactly the objects and properties invoked in your mental description of the creature relate to the physical objects and properties a theory of the creature's organ of mentation would introduce. You wonder, in par ticular, whether the ontologies can be identified and whether there are psychophysical laws. Now those who think the mind-body problem, construed in my bipartite way, to be empirical or scientific in charac ter would claim that so far you are in no position at all to pronounce upon the truth of this pair of theses; certainly you do not, in the specified state of ignorance, have any rational ground for accepting anomalous monism. If you are to have any justified opinion on the matter, you must undertake appropriate empirical research, delving into the creature's mental organ and hunting for psychophysical correlations. To suppose otherwise is to be guilty of 'apriorism' of the worst kind. I want to claim, in opposition to this, that you already possess sufficient knowledge to return rational answers to these questions: you can produce good reasons for accepting an identity theory for mental particulars, as well as for doubting any nomological PHILOSOPHICAL MATERIALISM 175 correspondence between mental and physical properties. That is (roughly) the sense in which the questions admit of (and I think require5) a priori resolution. Accordingly, the arguments I shall of produce exploit general features of mental and physical concepts which we can be credited with implicit knowledge. And just because my considerations are thus metaphysical in character they are avail able to one in the state of psycho-physiological ignorance I described. n A number of philosophers have recently claimed, very plausibly, that - certain terms of our language the so-called natural kind terms display a characteristic syndrome of semantic features which dis tinguish them from certain other terms, aptly labelled nominal.6 Here, by way of reminder, is a summary list of such features, related in various ways: (i) our initial criteria of recognition for membership in the kind are epistemically contingent; (ii) our original naive classifications of objects into natural kinds are susceptible of revision in response to scientific investigation of the kinds; (iii) there is the prospect of eliminating (ordinary language) natural kind terms in favour of nomenclature drawn from a scientific theory of the kinds; (iv) the equivalence relation that collects objects into a given natural kind is a theoretical relation; (v) we can construct plausible 'Twin earth' cases for natural kind terms; (vi) the extension of a natural kind term is not fixed by the concepts speakers associate with the term a ('meanings are not in the head'); (vii) natural kind terms exhibit high degree of division of linguistic labour; (viii) a causal-historical theory of reference seems applicable to natural kind terms; (ix) the extension of a natural kind term is typically fixed by ostensi?n (natural kind terms are indexical in some way).7 It is not to my purpose to scrutinise or defend these theses now; what I want to note is the source of the claimed features. Their source resides, I think, in a conception of natural kinds appropriately designated realist: i.e., realism about what constitutes a natural kind of object is what underlies our acknowledgement of the listed features of the asso ciated terms. For we think of what determines a natural kind as independent of our conventions and knowledge: it is fixed, rather, by possession of a hidden real essence (to use Locke's term) or nature 176 COLIN McGINN whose proper characterisation it is the business of empirical science to labour to discover. It is this realist idea, I suggest, that generates the syndrome of features (i)?(ix).8 The basic point is simply that, natural kinds being determined by nature, terms introduced by speakers to denote such kinds do not carry in their sense a charac terisation of what in the world constitutes the denoted kind. This real constitution may or may not be discoverable by speakers, but it is certainly not comprised in their ordinary use and mastery of the term. The essence of a natural kind is real not nominal. Now, turning to the realm of the mental, we are driven to enquire whether mental predicates are natural kind terms in the foregoing sense. The issue is significant for determining the nature of mental properties and (hence) the shape of a science of psychology, or whether indeed there can be such a thing. It will be useful to divide the enquiry into two parts, according to the type of mental term in question.