  Aristotle's discussions on the best format for a deductive science in the Posterior Analytics reflect the practice of contemporary mathematics as taught and practiced in Plato's Academy, discussions there about the nature of mathematical sciences, and Aristotle's own discoveries in logic. Aristotle has two separate concerns. One evolves from his argument that there must be first, unprovable principles for any science, in order to avoid both circularity and infinite regresses. The other evolves from his view that demonstrations must be explanatory. (See subsections A, B, and C of §6, Demonstrations and Demonstrative Sciences, of the entry  Aristotle's logic.)