Abstract

Here is a common view. There exist things, and there exists stuff, where roughly, ‘thing’ is a count noun, and ‘stuff’ is a mass noun. Syntactically, ‘thing’ functions as a singular referring term that takes ‘a’ and ‘every’ and is subject to pluralisation, while ‘stuff’ functions as a plural referring term that takes ‘some’ and is not subject to pluralisation. Hence there exists a thing, and some stuff. Usual versions of the common view endorse two principles about portions of stuff. The first principle is that (temporal) mereological essentialism is true of portions (parcels, masses, quantities) of stuff, where mereological essentialism is the thesis that for any persisting object or portion of stuff, that object or stuff has the same parts at every time at which it exists. The second principle is that portions of stuff obey a principle of stuff composition: for any two portions of stuff P1 and P2, there exists a portion of stuff that is the fusion of P1 and P2. I argue that these two principles are inconsistent. In particular, since I am sympathetic to PSC, I argue that mereological essentialism is false of portions of stuff.