The causal principle — that a cause must have at least as much formal reality as the objective reality of its effect — is arcane and not derivable from sensory experience

One can see the concept of innateness at work behind the scenes in Descartes’ wax argument, but that passage is designed more to rid us of the idea that our deepest understanding of things comes from the senses than to defend innateness. It is in working out the implications of the wax discussion that we arrive at an innate abstract concept of spatial extension. Innateness is also at work, but again behind the scenes, in the central argument of the Meditations that takes us from the fact that we