Abstract
What authority do Plato and Aristotle possess in Late Antiquity, specifically for Olympiodorus of Alexandria? According to a current widespread view, the relationship of all Neoplatonists to the two Greek philosophers can be captured by two assumptions : the harmony between the two thinkers and the superiority, even the infallibility, of Plato. The present study first clarifies this notion of harmony in the light of the pedagogical context of the late commentaries and the principle of truth as unity underlying them, and secondly shows that the notion of infallibility hardly applies to Olympiodorus, given the Socratic conception he has of his own exegetical practice and some features of his actual practice.