We now begin our examination of Plato's radical, stern, and beautiful proposal for a self-sufficient human life. Plato's ethical thought, I shall argue, is continuous with the reflections about tuchē that we have uncovered in tragedy, responding to the same urgencies, giving shape to the same human ambitions. It is bolder and more single-minded in its pursuit of progress, but not without its own sense of the human cost of progress.

As we pursue our questions in Plato's works, two major problems confront us: development and dialogue. Plato is a courageously self-critical philosopher; he not only revises previous positions, he even subjects them to criticism within his dialogues themselves. This means that it can be dangerous to make a synthesis of positions from different works; and yet often, clearly, it can also be fruitful, even necessary. In Chapter 5, I defend my procedure in bringing together several dialogues of the ‘middle’ period as I work on Plato's views about true value. At the end of Chapter 4, I sketch what I see as the most important shifts in Plato's approach to our problems between the early Protagoras and the middle-period works; I stress the fundamental continuity between the two approaches. In Chapter 7 I argue that Plato, in the Phaedrus, systematically criticizes the middle-period view as insufficiently responsive to the positive role of vulnerable values in the good life. (This criticism is prepared by the Symposium's sympathetic portrayal of the life that it criticizes – Ch. 6.)