Nussbaum, Martha C., "The Protagoras: A Science of Practical Reasoning," The Fragility of Goodness: Luck and Ethics in Greek Tragedy and Philosophy, Cambridge, UK: Cambridge University Press, 2001, 89-121.

Excerpt:

Throughout the dialogues that we shall study here, Plato’s elaboration of radical ethical proposals is motivated by an acute sense of the problems caused by ungoverned luck in human life. The need of human beings for philosophy is, for him, deeply connected with their exposure to luck; the elimination of this exposure is a primary task of the philosophical art as he conceives it. His conception of this art in the Protagoras differs in certain ways from the conception worked out in dialogues of his ‘middle’ period.

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