In 87c–89c, Socrates pursues the line of argument from the previous section to establish the conclusion that virtue is teachable. Since they have agreed that it is teachable if and only if it is knowledge, he spends most of this section arguing that it is indeed a form of knowledge (87d–89a). But before drawing the conclusion that it is teachable, he also pauses to reject the possibility that it comes by nature (89a–b), something suggested by Meno at the very beginning of the dialogue.

VIRTUE AS KNOWLEDGE (87d–89a)

Socrates begins by laying down the hypothesis that virtue is good. Since all good things are beneficial, virtue must be beneficial. He then turns to consider the sorts of things often considered beneficial, starting with bodily or material assets such as health, strength, beauty and wealth. Although these sometimes benefit us, they only do so when used correctly; otherwise they harm us. Next he considers qualities of the soul, e.g. temperance, justice, courage, mental agility and magnificence. If any one of these is not some sort of knowledge, it may be either beneficial or harmful. If courage, for example, is not actually knowledge, it amounts to some sort of ‘daring’ (tharros), which results in good or harm, depending on whether it is used wisely. In sum, all qualities of the soul apart from knowledge itself end in happiness when guided by knowledge, but in the opposite when guided by ignorance. On their own, they are neither beneficial nor harmful.