Musements on American, Continental, and cross-tradition philosophical thought.
As I understand it, for Aristotle and then throughout most of the middle ages matter was one continuous substance, a thing without parts. I think it was Descartes and Malebranche who got the idea going that material substance had parts. Apparently the argument was then taken up mainly by the physicists who argued between stuff and particle theories of matter. Stuff is the origin of the field theory of the continuous wave. And of the ether. Leibniz, I think, also had no parts to substance.