The Greeks had their social conditions, and the Romans theirs.

Even the criminal lines are drawn differently, somewhat, here and there; and in a low stage of civilization a man may pass for normal who, in our time, would be described as weak in mind.

This makes it necessary that the standards of judgment of a given society should be determined by an actual examination of the society, and forbids us to say that the limits of variation which society in general will tolerate must be this or that.
We may say, then, that the man who is fit for social life _must be born to learn_.

The need of learning is his essential need.

It comes upon him from his birth.