Can substantial changes be qualitative changes?

Abstract

ASSUMING that every change is an event, the distinction between qualitative and substantial changes appears to be a distinction between two kinds of events. But we might wonder whether it is true that no event can be both qualitative and substantial (involve both qualitative and substantial change). Imagine a case where we take a rope (R) and fashion it into a hammock (H). (H is created out of R alone). Here we have an event (ER, say) wherein R changes qualitatively and an event (EH, say) wherein H begins to exist. Assuming that a qualitative event is an event whose subject changes qualitatively, and that a substantial event is an event whose subject either begins or ceases to exist, it seems that if ER= EH, then one event can fall both in the 'qualitative' and 'substantial' category. However, there is an obvious objection to this way of regarding the matter. ER's subject is rope R, EH's subject is hammock H. Since (or assuming that) R exists before H, R and H are distinct objects, which means that ER and EH have different subjects. Assuming that one event can't have two (or more) subjects, it follows that it is not true that ER = EH. Lawrence Lombard argues' that 'when an object with parts comes into or goes out of existence, there is no single thing such that a change in it is what the object's coming into or going out of existence consists in.' Since H has parts, Lombard would deny that event EH can be identified with ER. Two events occur, one of which involves a qualitative change and the other a substantial change. However, Lombard could not consistently base his denial that ER=EH upon the premise that one event can't have more than one subject, since he endorses: