The moral psychology put forth by Socrates in the Protagoras is customarily treated as an anomaly that must be discounted or dismissed as not authentically Platonic. Socrates asserts that all choices are determined by the perception of pleasure and pain and, on this basis, argues that akrasia is impossible. In this paper, I argue that these two key elements of the Protagoras’ moral psychology are fully embraced in the Republic and should be considered authentically Platonic.