“Lastly, what is history for? This is perhaps a harder question than the others; a man who answers it will have to reflect rather more widely than a man who answers the three we have answered already. He must reflect not only on historical thinking but on other things as well, because to say that something is `for' something implies a distinction between A and B, where A is good for something and B is that for which something is good. But I will suggest an answer, and express the opinion that no historian would reject it, although the further questions to which it gives rise are numerous and difficult.
My answer is that history is `for' human self-knowledge. It is generally thought to be of importance to man that he should know himself: where knowing himself means knowing not his merely personal peculiarities, the things that distinguish him from other men, but his nature as man. Knowing yourself means knowing, first, what it is to be a man; secondly, knowing what it is to be the kind of man you are; and thirdly, knowing what it is to be the man you are and nobody else is. Knowing yourself means knowing what you can do; and since nobody knows what he can do until he tries, the only clue to what man can do is what man has done. The value of history, then, is that it teaches us what man has done and thus what man is.”

Source: The Idea of History (1946), p. 10