Cropsey, Joseph, "Protagoras," Plato's World: Man's Place in the Cosmos, Chicago, IL: University of Chicago Press, 1995, 3-26.

Excerpt:

Given the dialectical character of the Platonic writings individually, it is not surprising that the Platonic corpus as a whole consists as largely as it does of engagements with one or another alternative to the understandings of Plato/Socrates. It belongs to the genius of Plato that he constructed a universe out of elements that exist in a condition of mutual (dialectical) tension, in a tacit, however limited, concession to the cosmology of Stress.

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