Unity of Virtues according to Socrates and Protagoras

This article deals with the nature of virtues in the Protagoras dialogue and introduces Socrates' and Protagoras' arguments on this issue, and analyzes the logical foundation of their arguments. The difference between Socrates and Protagoras regarding the notion of 'unity of virtues' is due to two different logics of thought. Socrates represents the mental logic, which is based on the principle of conformity and paradox. This logic aims to reach the 'whole,' where knowledge constitutes the measure of judgment, and seeks to reach the desired thing and what should be. Protagoras, however, represents the sensory logic that depends on the principle of 'similarity and dissimilarity." The human being is the measureof the existence and non-existence of things;it is a relative logic that deals with the existent thing and attributes everything to the senses.