Aristotle's Exposition of Principles

Aristotle's exposition does not begin with the deepest insights and most fundamental principles, but goes gradually from the obvious to the obscure. Zabarala offers a few examples of this from Aristotle's texts. We feel heat every day, but don't realize it is caused by the element of fire or in modern physics the agitation of particles in a body. Prime matter is what underlies all change, so it is the principle that explains why natural bodies are changeable.