Abstract

In the paper Plantinga refers to, I had set forth three axioms for what I had called the strict and philosophical sense of the term "part," or "proper part." These axioms tell us, in effect, that the expression "x is an S-part of y" expresses a relation that is transitive, asymmetric, and such that x bears it to y at all times that y exists. The latter clause may be put in Plantinga’s terms by saying "x bears it to y at every time in every world in which y exists." Plantinga points out that there are several other relations that also have these properties, for example, the relation of proper set inclusion among sets of contingent objects. He asks, therefore, whether it is possible to supplement my three axioms in such a way that they single out properties that are peculiar to the relation of strict proper part.