With the translation of all Aristotle's known works from Greek and Arabic into Latin during the twelfth and thirteenth centuries, western Europeans had access to a "complete system" of philosophy. That is, logic, epistemology, metaphysics, natural philosophy, philosophy of mind, and ethics were presented in what looked like systematic order. Medieval philosophers responded to this new body of knowledge by attempting to integrate it with previously established philosophical systems, constructing their own syntheses by combining elements of Neoplatonism, Stoicism, Aristotelianism, and Christianity.

Aristotle's Major Contributions. First, Aristotle provided a logical method for analyzing arguments, the syllogism, a form of argument that includes a major premise, a minor premise, and a conclusion. (For example: All boys like baseball. John is a boy. Therefore, John likes baseball.) Second, he provided a theory of proof (demonstration) with links to what became Euclidian geometry. This theory...