 While Descartes does claim (at least most of the time) that individual bodies are distinct substances, he does not invoke this claim in his official account of the individuation of bodies. The account he does offer is highly problematic. Descartes holds “all the variety in matter, and all the diversity of its forms, depends on motion” (Principles 2.23). Thus the distinction between bodies is constituted of distinctions in the motions of regions of extension. On the other hand, Descartes defines motion “in the strict sense of the term”, as the relative change of position of a body relative to those bodies with which it is immediate contact (Principles 2.25). The circularity here is obvious, and crippling. Diversity and variety of bodies depends on motion, but motion depends upon a prior distinction between bodies.