If Aristotle's system combines metaphysics and biology in a two-pronged assault on the "reign of chance" characteristic of ancient atomism, the Renaissance and early modernity witness the emergence of two curious intellectual formations: on the one hand, a kind of naturalized Aristotelianism, with figures like Pomponazzi, influencing important works of the anonymous, clandestine tradition like the Theophrastus redivivus and its critique of "the gods"; on the other hand, a renewed interest in both the metaphysics of a chaotic universe (along with its possible ethics), and, in response to cases such as fossil evidence, what I"ll call the metaphysics of transformism. Transformism comes hand in hand, in the authors we examine, with a unique form of "embodied" determinism, inspired by Lucretius and very distinct from the predictability-oriented forms of determinism we are familiar with post-Laplace.