 One may in fact argue on these grounds that the parthood relation is in some sense conceptually prior to the identity relation (as in Sharvy 1983: 234), and since ‘EQ’ is not definable in terms of ‘PP’ or ‘PE’ alone except in the presence of stronger axioms (see below ad (27)), the argument would also provide evidence in favor of ‘P’ as the most fundamental primitive. As we shall see in Section 3.2, however, the link between parthood and identity is philosophically problematic. In order not to compromise our exposition, we shall therefore keep to a language containing both ‘P’ and ‘=’ as primitives. This will also be convenient in view of the previous remarks concerning the controversial status of Antisymmetry, on which (26) depends.