Aristotle had a lifelong interest in the study of nature. He investigated a variety of different topics, ranging from general issues like motion, causation, place and time, to systematic explorations and explanations of natural phenomena across different kinds of natural entities. These different inquiries are integrated into the framework of a single overarching enterprise describing the domain of natural entities. Aristotle provides the general theoretical framework for this enterprise in his Physics, a treatise which divides into two main parts, the first an inquiry into nature (books 1–4) and the second a treatment of motion (books 5–8).[1] In this work, Aristotle sets out the conceptual apparatus for his analysis, provides definitions of his fundamental concepts, and argues for specific theses about motion, causation, place and time, and establishes in bk. 8 the existence of the unmoved mover of the universe, a supra-physical entity, without which the physical domain could not remain in existence. He takes up problems of special interest to physics (such as the problem of generation and perishing) in a series of further physical treatises, some of which are devoted to particular physical domains: the De generatione et corruptione (On Generation and Perishing), the De caelo (On the Heavens),[2] and the Meteorology, which lead up to the treatises on biology and psychology.[3]
The science of physics, Aristotle stresses, contains almost all there is to know about the world. Were there no separate forms—entities such as the unmoved mover at the pinnacle of the cosmos—which are without matter and are not part of the physical world, physics would be what Aristotle calls first philosophy (Metaphysics 6.1, 1026a27–31). As there are such separate entities, physics is dependent on these, and is only a second philosophy (Metaphysics 7.11, 1037a14f). Nevertheless, the interaction between these two “philosophies” is not completely exhausted by the causal influence exerted on the world by the supra-physical entities—the prime movers as it turns out. Aristotle’s metaphysics and physics use a common conceptual framework, and they often address similar issues.
