Type/Token Distinction — A logical and metaphysical distinction introduced by Charles Sanders Peirce in “Prolegomena to an Apology for Pragmaticism” (The Monist, 1906), separating two ways of counting entities. When one says the word “the” appears dozens of times on a page, “word” is being used in two senses: the type is the word as an abstract category, the single form or pattern; the tokens are the particular, concrete occurrences of that word, each occupying a place in space and time and possessing physical properties (colour of ink, size). The sequence “cat cat” thus contains two tokens but only one type. The relation between the two is one of instantiation, analogous to — but not identical with — the relation between a universal and its particulars: a type exists insofar as there are, or could be, tokens that realise it. In philosophy of language the distinction is ubiquitous: sentences are types, utterances are tokens, and from this arises the question of whether meaning belongs to the type or the token. Nelson Goodman extended the idea to the arts in Languages of Art (1968), treating a musical work as a type and each performance as a token. In philosophy of mind it structures the debate over physicalism: type-type identity theory (Place, Smart) identifies each type of mental state with a type of neural state, whereas Donald Davidson’s token-token identity, in “Mental Events” (1970), identifies only particular occurrences and denies strict psychophysical laws — his anomalous monism. The problem of multiple realisability, raised by Hilary Putnam, is the chief objection to type-type identity.
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