Page 53 - Encyclopedia of Philosophy of Language

'narrow,' just as MSrequires. The article on Inten- tionality discusses some of these issues more fully.
Bibliography
Block N 1986 Advertisement for a semantics for psychology. In: French P A, Uehling T E, Wettstein H K (eds.) Midwest Studies in Philosophy, vol. 10. University of Minnesota Press, Minneapolis, MN
Davidson D 1987 Knowing one's own mind. Proceedings and Addresses of the American Philosophical Association 60(3): 441-58
Fodor J A 1980 Methodological solipsism considered as a research strategy in cognitive psychology. Behavioral and Brain Sciences3: 63-109
Fodor J A 1987 Psychosemantics. MIT Press, Cambridge, MA
McGinn C 1982 The structure of content. In: Woodfield A (ed.)
Putnam H 1975 The meaning of 'meaning.' In: Mind, Language and Reality: Philosophical Papers, vol. 2. Cam- bridge University Press, Cambridge
Schiffer S 1981 Truth and the theory of content. In: Parret H, Bouveresse J (eds.) Meaning and Understanding, de Gruyter, Berlin
Stich S 1983 From Folk Psychology to Cognitive Science. MIT Press, Cambridge, MA
Woodfield A (ed.) 1982 Thought and Object. Clarendon Press, Oxford
There is less agreement on what 'natural kinds' them- selves are than on what natural kind 'terms' are. The latter are a species of general term and fall into two classes, sortal terms and mass terms, though not all terms in these two classes are natural kind terms. Examples falling into the first class are tiger and lemon while examples falling into the second are water and gold. Natural kind terms are often contrasted with terms for artefactual kinds, like pencil and yacht, one important distinguishing feature being that the former but not the latter typically feature in statements of natural scientificlaw.
1. The Semantics of Natural Kind Terms
According to philosophers like Saul Kripke and Hil- ary Putnam, whose work in this area has been most influential, natural kind terms have a number of dis- tinctive semantic characteristics which set them apart from other general terms. In particular, Kripke holds that natural kind terms are, like proper names, rigid designators and accordingly that they are not defin- able in terms of complex descriptions in the way that empiricist philosophers like John Locke had supposed. Locke believed that a general term like water signified an abstract idea composed of the ideas of various observable properties which the user of that term took to be the essential or defining characteristics of a certain kind of substance. This abstract idea con- stituted the 'nominal essence' of water for that speaker, to be distinguished from water's 'real essence,' which Locke took to be its (then unknown) internal physico-chemical constitution and which
modern science has since identified as its molecular structure, H2O. In Locke's view it is a purely con- tingent fact that water,as ordinary English speakers understand that term, designates H2O. Kripke, by contrast, holds that water rigidly designates H2O and consequently that water is H2O is a necessary truth, albeit not an a priori truth.
Putnam has argued that the rigidity of natural kind terms follows from their having a quasi-indexical sem- antic status, deriving from the role that demonstrated specimens play in the identification of the referents of such terms. For Putnam, gold, for example, refers to any metal which is relevantly similar in its internal physico-chemical structure to the samples which competent users of the term in a specific linguistic community would characterize by saying This is gold. He points out too that one would defer to the opinion of experts when in doubt as to whether some- thing is gold and consequently that the use of such natural kind terms is subject to what he calls a 'div- ision of linguistic labor.' Finally, Putnam contends that although natural kind terms are associated in speakers' minds with 'stereotypes' (for instance,
Natural Kinds £. J. Lowe
the stereotypical
these stereotypes
ideas, determine
conditions for membership of the associated natural kinds.
tiger is striped and four-legged), do not, unlike Lockean abstract logically necessary and sufficient
2. The Ontology of Natural Kinds
As to what natural kinds are, ontologically speaking, no consensus presently exists. Some metaphysicians
Natural Kinds
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