Malebranche is both an occasionalist and an advocate of the preformationist theory of generation. One might expect this given that he is a mechanist: passive matter cannot be the source of its own motion and so requires God to move it (occasionalism); and such matter, moving according to a few simple laws of motion, could never fashion something as complex as a living being, and so organisms must be fashioned by God at Creation (preformationism). This expectation finds a challenge in Kant's depiction of the relation between causation and generation. According to Kant, preformation is the generation theory one would expect the advocate of the pre-established harmony to endorse, while the occasionalist would endorse a theory whereby God directly forms the organism upon every insemination. I make sense of Malebranche's position in light of Kant's suggestion by examining the relation Malebranche sees between science and metaphysics, the roles that he believes empirical investigations and final causes have in scientific practice and explanation, and the role of the supernatural in Malebranche's philosophy.