Universalism and extensionalism revisited

Abstract We present a new notion of mereological sum that is inequivalent to extant ones in the literature and does not fall prey reasonable complaints can be raised against some such notions. In light this notion, we then revisit relation between universalism extensionalism. particular argue Varzi’s claim point entails extensionalism justified only insofar as one sticks sum. effect, distinguish different versions universalism—when cashed out terms our sum—entails but others. Most significantly it entail extensionality proper parthood. above set forth system, Universalist Quasi-Supplemented Mereology, considered worthy alternative systems literature.