In order to fully understand Aristotle's views on a natural system, it is necessary to first explain some general principles of his philosophy. It is in his work the Categories that Aristotle presents the concept of substance, a concept which will serve as the foundation for much of his philosophical system. Substance, for Aristotle, is not a universal, but rather, it is the particular; substance is not a “such,” but a “this.” Thus, substance is neither in nor is it said of a subject (as are qualities). Rather it is that which make ....