During the 1660s, Cartesian philosophers had to defend some of the most radical views concerning animal life in general and soul in particular, departing from Aristotelian views. Earlier questions and curiosities about the consequences of Descartes’s system became subject to full-scale criticism from traditional scholars but also from other inquisitive thinkers. The wave of opposition was anticipated by a series of Cartesian publications from the 1660s, when some of the writings defended different versions of the animal-machine theory. In this paper, I will present one of such instances: a short treatise by Géraud de Cordemoy, published anonymously in 1668 as “Une lettre écrite à un sçavant religieux de la Compagnie de Jésus.” I explain how Cordemoy attempts to defend Descartes’s philosophy through a comparison between the Biblical history of Creation and Descartes’s cosmological account. I focus on the discussion concerning animal life and explore Cordemoy’s rhetorical strategy in defending the view that Descartes’s “Opinion concerning Brutes does contain nothing dangerous; and that all he hath written of both seems to have been taken out of the First Chapter of Genesis.”