Stuff and Things

Abstract

Metaphysical problems often concern the relation between various types of entities or putative entities. Philosophers at least since Aristotle have puzzled over the relation between particulars and universals, substances and things, movements and actions. Debate over the first of these issues still continues, but I think it is fair to say that there was an increase in clarity when, around the turn of the century, the notion of a set was made clearer and more explicit. For the purposes of logic, at least, the use of a set of objects as the analogue of a universal has been quite fruitful. Interpreting a predicate by means of a set of ordered n-tuples has provided a precise characterization of the semantics of the language which has led to interesting metatheoretical and philosophical consequences. There are still some problems which are not resolved by this approach. For example, it seems intuitively plausible that there could be two distinct universals with the same instances. Nevertheless, the approach at least gives an unproblematic theory of truth for sentences involving only particulars and universals. The issue about distinct universals with the same instances is a disputed one and in any case the set theoretic view enables one to give a sharp statement of the issue in dispute.

I am indebted to Brian Chellas, Kathleen Cook and David Rosenthal for helpful comments on an earlier version of this paper which was read at the APA Eastern Division meetings in December, 1973.