What is reason? A number of contemporary philosophical schools of thought have sought, implicitly or explicitly, to answer the question. That an answer to the question be found is of utmost importance for the practice of philosophy, and yet none seems to be forthcoming, In this thesis, we propose to examine Plato's concept of reason. Our method in the thesis, however, is to proceed negatively: first, we examine the misology passage from the Phaedo 89d: why is the greatest evil to become a misologue (hater of reason)? What does this say about Plato's conception of reason? What is the connection between reason, pleasure, and pain? Next, we move to the Phaedrus, where a more constructive account is offered. Reason is a capacity, actuated by beauty, of receiving being. It thus involves a crucial moment of passivity. We will examine the consequences of such a conception, and offer our own commentary.