 We use the subscript “X” because, in line with foregoing remarks, it seems appropriate to call this species of ontological dependence eXplanatory existential dependence. (We shall need the subscript “E” for another use later.) Here it is important to note that the presence of the word “only” in (EDX)’s definiens should not be understood as implying that an object x may not dependX for its existence upon two (or more) different things, y and z. Thus the particularized relation of Mary’s loving Tom—supposing such an object to exist—plausibly exists only because Mary exists, but plausibly also exists only because Tom exists. Furthermore, we may assume that it is not an implication of (EDX) that a composite object dependsX for its existence upon its proper parts, that is, that it is not the case that it “exists only because they exist”—on the grounds that it could still exist in the absence of those particular parts, provided suitable alternative parts were substituted for them. Thus (EDX) is quite unlike  (EDG)  in its implications for part-whole dependence relations, as far as composite objects are concerned. For the same reason, we may assume that (EDX) does not imply that an “Aristotelian” universal dependsX for its existence upon its particular exemplars. Indeed, we may take it that the definiens of (EDX) entails the definiens of  (EDR)—although  not vice versa, of course—so that the following is a principle that one could accept: