Aristotle did not share Plato’s belief that all knowledge could be founded upon a single set of axioms. ‘The Structure of the Sciences’ shows that Aristotle divided knowledge into three major classes. The productive sciences are concerned with making things; Aristotle himself had relatively little to say about these. The practical sciences are concerned with how we ought to act in various circumstances, in private and public affairs. The Ethics and the Politics are Aristotle’s chief contributions here. Theoretical knowledge includes everything now considered science, and in Aristotle’s view it contains most of human knowledge. It subdivides into mathematics, natural science, and theology (closer in practice to astronomy).