The Metaphysics of Mental Causation

is "what is got before the mind by an act of abstraction." It is what comes to be known by attending to some part, or aspect, of "what is presented."18 In contrast, what is concrete is grasped by at tending to all of what is presented, not by attending to some part or aspect of it. No special act of selective attending is involved in our grasp of concrete things. 17 Campbell, "The Metaphysic of Abstract Particulars," in French et al., eds., Midwest Studies in Philosophy, Volume 6 (Notre Dame: University Press, 1981), pp. 477-88; and Abstract Particulars (Cambridge: Blackwell, 1990). 18 Campbell, Abstract Particulars, p. 48. This sense of 'abstract' is different from an other, and more common understanding of the term in metaphysics. According to it, entities of a given kind are abstract if they are such that many of them can be in the same place at the same time. It contrasts with the sense of 'concrete', where to be concrete is to exclude other things of the same kind occupying the same space at the same time. 548 THE JOURNAL OF PHILOSOPHY Campbell's work is a revival of the earlier foundational work of Donald C. Williams.19 Williams set forth a version of trope theory that is now regarded as the classic account.20 This account will serve as the standard against which to evaluate the strategy of appealing to trope theory in order to resolve the problem of the causal relevance of mental properties. According to the classic account, tropes are the foundations of all things, and so are the foundations of both individual objects and events, and properties or universals if there are any. Individual objects are bundles of compresent or concurrent tropes, tropes that are "bun dled" together by relations of compresence. For example, this red ness, this shape, this size, and this position (along with other tropes), related to one another by compresence relations, together "consti tute" or comprise the cardinal sitting on the branch of the tree out side my window. And individual events are either tropes, or bundles of compresent tropes.21 Properties or universals, and relations are classes or sets of exactly resembling tropes. Individual tropes (for example, all the rednesses of all the red things) that are members of the class or set of exactly resembling tropes with which a given property is identical are under stood to be particular trope-instances of that property. For a sub stance or event to instantiate a property (universal, relation) is for the intersection of the set of compresent tropes that constitute the in dividual substance or event and the set of tropes that is the property to be nonempty. III. TROPE THEORY AND THE PROBLEM OF THE CAUSAL RELEVANCE OF