At the beginning of ch. xxv (3516) Socrates starts once more to prove his contention that courage is a form of wisdom. He begins by asking Protagoras whether pleasure is not always in itself good, pain in itself evil. Protagoras is not prepared to admit this, but he is willing to accept the position as a basis for discussion. Socrates then asks a second question (352a 8): does Protagoras, like most people, think that knowledge has no power or authority in the soul? does he think that knowledge may be present and yet not operative, being knocked about like a slave by the superior force of anger, pleasure, or passion? Must we not rather believe that knowledge can be conquered by nothing and is alone sufficient to salvation?