 Several fundamental and distinctive issues of interpretation pertaining to the physical arise from this picture. How are bodies to be conceived, if not as independent substances? How are motion and rest to be conceived so as to make sense of the claim that bodies are individuated by them? How are the principles of inertia and the collision laws that follow from it to be accounted for, given that they cannot be grounded in God's immutable will? What is the nature of the individual striving of bodies, and how can it be reconciled with Spinoza's deterministic dynamics of Extension? These issues cannot be addressed independently of one another. The present discussion will approach them as they emerge from Spinoza's engagement with Cartesian physics, beginning with the PCP‘s exposition of Descartes’ views.