  One of the more controversial positions the Principles forwarded, at least according to Newton, was that a vacuum was impossible. Descartes’ rejection of the possibility of a vacuum followed from his commitment to the view that the essence of body was extension. Given that extension is an attribute, and that nothing cannot possess any attributes (AT VIIIA 25; CSM I 210), it follows that “nothingness cannot possess any extension” (AT VIIIA 50; CSM I 231). So, any instance of extension would entail the presence of some substance (AT VIIIA 25; CSM I 210). In other words, vacuum, taken as an extended nothing, is a flat contradiction. The corporeal universe is thus a plenum, individual bodies separated only by their surfaces. Newton argued in his De Gravitatione and Principia that the concept of motion becomes problematic if the universe is taken to be a plenum. Another controversial position was Descartes’ insistence that matter is infinitely divisible.  Gassendi, and later Cordemoy, argued that there must be a bottom, a ‘substance,’ to the physical universe upon which the being of all corporeal things depend. In line with the ancient atomist Epicurus, they argued that if matter was infinitely divisible, so dividing it would show that there was no bottom—and so, corporeality would not be substantial. So, if corporeality is substantial, as Descartes himself had claimed, there must be a minimum measure of extension that could not be divided (by natural means, anyway). And so, there are atoms.  But, this conclusion is something that Descartes explicitly rejects in the Principles.