 During his long career, Walter Burley worked out two different accounts of the standard realist theory of knowledge, both of which are critical of the most common theories of his time. Burley himself places much more stress on the question of the proper object of human knowledge and the intellective cognition of individuals. The first account is developed in his commentary on Aristotle’s De anima (before 1316), and the second in the prologue of his last commentary on the Physics (around 1324).