Question

Philosophy:

For Descartes, what constitutes body, or corporeal substance? What constitutes mind, or thinking substance?

Answer 1

Descartes believed in only two kinds of substance: material body, which is defined by extension, and mental substance, which is defined by thought, which, is more or less equivalent to consciousness. Descartes did not believe in a void between bodies, so there is a sense in which there is just one material substance, numerically as well as specifically. The situation is different for mental substance. The cogito shows that Descartes definitely believes that each person is a different individual mental substance.