In 'Kinds and the Dilemma of Individuation '1 Michael J. Loux tries his hand at solving a problem which has drawn a great deal of attention in the literature ot" contemporary realism. The realist, committed to the idea that things are, at least in part, constituted of the characteristics they exemplify, and that those characteristics are universals (numerically identical in their instances), must come to terms with the possibility of the occurrence of two objects the same with respect to all of their nonrelational characteristics (qualities). Most will agree that such situations are possible, indeed, actually occur. The task which confronts the realist, then, is to account for the numerical diversity of qualitatively indistinguishable objects -the problem of individuation.
Several solutions to this problem have been proposed, and two have received by far the most attention as well as criticism: the doctrine of bare particulars 2 and the thesis that relations individuate 3. Neither enjoys anything like universal support among realists and, to date, the situation in the realist camp is, at best, unsettled.
In this setting Loux, a realist, proposes a solution to the problem of individuation which would allow the realist to abandon the bare particular and repudiate relational individuation. His thesis draws on Aristotle's account of universals such as man or dog. Unlike universals such as whiteness the instances of which are, according to the realist, numerically identical, the instances of the universal or kind man are always numerically diverse. Loux suggests that if all objects, in addition to exemplifying universals of the former sort, also exemplify at least one kind (or, as Loux prefers, substance-kind), then we may say that that which accounts for the individuality of any object is the substance-kind to which it belongs. Loux argues (correctly, I believe) that substance-kinds cannot be reduced to one or more qualities, and concludes,