ABSTRACT
Aristotle recognizes a variety of ways in which one thing is separable from another: in account, in being, in function, in place, in magnitude, in thought, simpliciter, and perhaps others as well. Aristotle argues that one cannot explain completely several characteristics of an organism's tissues and organs if one does not explain them as coming to be as they are for the intellect's sake. Natural science studies natures and Aristotle is clear that the principle and cause of a living organism's vital activities, including its intellectual activities, is its form, viz. its soul, and that souls are natures. Aristotle offers numerous descriptions of what the student of nature studies: Some of these descriptions are meant to fix natural science's domain; others are meant merely to describe salient and important characteristics of that which belongs to natural science's domain.
