It proceeds from the same question--Is virtue teachable ?--Sokrates as usual expressing his doubts on the point.
Protagoras then delivers a splendid harangue, showing how virtue is taught--namely, by the practice of society in approving, condemning, rewarding, punishing the actions of individuals.

From childhood upward, every human being in society is a witness to the moral procedure of society, and by degrees both knows, and conforms to, the maxims of virtue of the society.

Protagoras himself as a professed teacher, or sophist, can improve but little upon, this habitual inculcation.

Sokrates, at the end of the harangue, puts in his usual questions tending to bring out the essence or definition of virtue, and soon drives Protagoras into a corner, bringing him to admit a view nowhere else developed in Plato, that Pleasure is the only good, Pain the only evil, and that the science of Good and Evil consists in Measuring, and in choosing between conflicting pleasures and pains--preferring the greater pleasure to the less, the less pain to the greater.

For example, courage is a wise estimate of things terrible and things not terrible.