Greek philosopher who was first of all a disciple of Plato before distancing himself from him and becoming the tutor of Alexander the Great. Above all a scholar and teacher, he founded in Athens his own school, the Lyceum. His intellectual activity embraced every domain of thought, as the titles of his principal works signal: Physics, Metaphysics, Logic, Rhetoric, and Nicomachean Ethics. Setting himself against the Platonic world of Ideas – too abstract for his taste – he anchored his thinking essentially on the concrete or the material. The morality he moreover advocated, opposed to a too acute idealism, is that of the happy medium: the courageous attitude, for example, must as much avoid the foibles of cowardice as that of an unbridled recklessness.