It is said that those who fail to remember history are doomed to repeat it. That’s not quite correct. We all forget history. The key is whether we have a way to go back to rediscover what we forget. More directly, the key is whether an objective past can keep us honest.

A nation is the sum of its memories, and when those memories are allowed to die, it is less of a nation. (p. 35)

A people's memory is history; and as a man without a memory, so a people without a history cannot grow wiser, better.

Memory is the central part of the individual identity… and I think that’s true with a nation, too. What a nation is how the nation remembers its past, and with the authoritarian government in China, so far recent history has been written in the authorities’ narrative; how they came into power, and what has happened since they came into power, have been revised in a way that fits into the official narrative.

In the words of a very famous dead person, 'A nation that does not know its history is doomed to do poorly on the Scholastic Aptitude Test.

History is a people's memory, and without a memory, a man is demoted to the lower animals.

A nation that forgets its past has no future

With all the stir made about education, the ignorance of our own country's history is something lamentable and appalling and depressing.

Were a man to be totally deprived of memory, he would be incapable of forming any just opinion; everything about him would seem a chaos: he would have even his own history to ask from every one; and by not knowing how the world went in his absence, he would be at a loss to know how it ought to go on when he recovered, or rather, returned to it again. In like manner, though in a less degree, a too great inattention to past occurrences retards and bewilders our judgment in everything; while, on the contrary, by comparing what is past with what is present, we frequently hit on the true character of both, and become wise with very little trouble.

There's an old saying about those who forget history. I don't remember it, but it's good.

...I’m always shocked by the lack of historical awareness on the part of the average American. Many of the people who have come here did so to forget history, to turn their backs on history.

History is the consequence not only of people’s actions, but also of their forgetfulness.

This is what seems to me the grave, perhaps the gravest, evil of our time. For history is always somewhat false, and by its falsehood always somewhat warps judgment; but history written on the basis of deliberate falsehood and of repeated and prolonged suppression would be another matter altogether. It would not be history at all.
Now history is the memory of the race; and a man without memory is no longer a man.

El pasado es también el presente y el futuro. La nación que olvida está pérdida.