ABSTRACT
Aristotle’s overall aim in book XII is to investigate changing things, and nature in general, as a whole-to investigate the universe (to pan, literally ‘the all’, i.e. the totality of things) as a whole (hōs holon ti, XII. 1, 1069a19). He will undertake this investigation by searching for the principles and explanations of all things, and of the universe and nature as a whole. By nature, phusis, he will mean the totality of changing things. But he will argue (in XII. 6-10) for a very distinctive conclusion. For he will argue that the totality of changing things, and nature as a whole, has a single ultimate explanation and cause, which is itself changeless and which is distinct from nature as a whole. What this explanation explains is, in general, why there is such a thing as change in the first place. But in particular it explains why there is such a thing as regular and uniform change, and in general change that is intelligible and subject to explanation-what we may call rational change. He will eventually call this ultimate explanation of rational change: God.
