  The relation between types and their tokens is obviously dependent on what a type is. If it is a set, as Quine (1987, p. 217) maintains, the relation is class membership. If it is a kind, as Wolterstorff maintains, the relation is kind-membership. If it is a law, as Peirce maintains, it is something else again, perhaps being used in accordance with. (Although Peirce also says a token is an “instance” of a type and that the token signifies the type.) Nonetheless, it has often been taken to be the relation of instantiation, or exemplification; a token is an instance of a type; it exemplifies the type. (Not that every instance of a type is a token—e.g. capital ‘A’, small ‘A’, and all the other types of ‘A’s tokened in the display in §4.2 above may be said to be instances of the letter ‘A’.) As with other universals, there are two versions of this relation, Platonic and Aristotelian. Although the two versions of property realism are discussed at length under this encyclopedia's entry for properties, a few remarks about the type versions are in order.