After reading the entire second part, I found out that this part did not discuss the definition of virtue as in the first part. The second part is roughly about the source of knowledge that Socrates and Meno are discussing. Socrates believes that knowledge is not taught. He believes that knowledge is a kind of memory, something that is engraved into the soul. Socrates also believes that knowledge can be triggered by asking questions to trigger memories in the soul.

Socrates：
Now if he always had it, he was always in a state of knowing; and if he acquired it all some time, he could not have acquired it in this life. Or has someone taught him geometry? You see, he can do the same as this with all geometry and every branch of knowledge. Now, can anyone have taught him all this? You ought surely to know, especially as he was born and bred in your house.
Meno：
Well, I know that no one has ever taught him.
Socrates：
And has he these opinions, or has he not?
Meno：
He must have them, Socrates, evidently.
Socrates：
And if he did not acquire them in this present life, is it not obvious at once that he had them and learnt them during some other time?
Meno：
Apparently.
Socrates
And this must have been the time when he was not a human being?
Meno
Yes.

This paragraph is that Socrates persuaded Meno’s knowledge to be engraved in the soul. In fact, if you look at it from the perspective of Socrates, he is really right. But carefully read the dialogue between Socrates and the boy, you will find that he is constantly educating the boy through the inducing. The boy has a certain mathematical foundation, so Socrates broke through a question by asking questions, slowly inducing the boy to learn new knowledge and go to find the answer himself. Is this not a kind of teaching?

Socrates is the “most intelligent” person in Greece. If he is the leader of a cult, he will succeed in brainwashing most of the people. The way of inducing can not only teach the boy, but also make us convinced. If, as he said, knowledge is preserved in the soul, then is there something else in our soul? For example, I used to be a warrior. I came back to the world through reincarnation. Then, when I am in danger, can I trigger the memories and skills that I used to be warriors? It may also be that my knowledge is too shallow and I can’t understand the idea of ​​thinking like Socrates.