Belief in a purely objective understanding of such concepts as justice, love, and virtue, and the self-knowledge that he inculcated, were the basis of his teachings. He believed that all vice is the result of ignorance, and that no person is willingly bad; correspondingly, virtue is knowledge, and those who know the right will act rightly. His logic placed particular emphasis on rational argument and the quest for general definitions, as evidenced in the writings of his younger contemporary and pupil, Plato, and of Plato's pupil, Aristotle. Through the writings of these philosophers, Socrates profoundly affected the entire subsequent course of Western speculative thought. He was basically the first philosopher. There were other philosophers before him, but Plato was taught by Socrates, and Aristotle from Plato. (Alexander the Great would study under Aristotle. Aristotle would also add a great deal to philosophy) So Socrates more or less led to the greatest minds after him as well as contributing to the field himself. Socrates is also seen as a tragic figure, because he educated the children of Athens to think for themselves and angered many of the town