There are many "idealist" critiques of materialism, including as a natural philosophy. Early modern critiques often invoke a notion of 'soul" or "life" as a feature which the materialist either eliminates, or at least cannot account for. Here I examine an early and powerful critique of materialism in Aristotle, which brings out both his subtlety with regard to the nature of biological entities and, perhaps, his desire to find a "third way" between the pure idealism of Platonic forms and the equally pure chance-and-necessity of the atomists, who he calls the phusiologoi.