This is the paradox of historical knowledge. Knowledge that does not change behaviour is useless. But knowledge that changes behaviour loses its relevance. The more data we have and the better we understand history, the faster history alters its course, and the faster our knowledge becomes outdated.

the better we understand history, the faster history alters its course, and the faster our knowledge becomes outdated.

History teaches us that a given view has been abandoned in favor of another by all men, or by all competent men, or perhaps by only the most vocal men; it does not teach us whether the change was sound or whether the rejected view deserved to be rejected. Only an impartial analysis of the view in question—an analysis that is not dazzled by the victory or stunned by the defeat of the adherents of the view concerned—could teach us anything regarding the worth of the view and hence regarding the meaning of the historical change.

The careful study of history is of hight value - among other reasons because it may instruct us, sometimes, concerning ways to deal with our present cisontentk. I do not mean simply that history repeats itself, or repeats itself with variation - although there is something in that, and particularly in the history of revolutions on the French model, which devour their own children. I am suggesting, rather, that deficiency in historical perspective leads to the ruinous blunders of ideologues, whom Burckhardt calls "the terrible simplifiers," while sound historical knowledge may diminish the force of Hegel's aphorism that "we learn from history that we learn nothing from history."

G. H. Hardy in his apology for pure mathematics placed high among his arguments that the subject was "harmless". I can – alas – make no such plea for history. The correct use of historical study may be debatable, but the consequences of its abuse have been made plain for all the world to see. The propagandist use of history in the Germany of yesterday, in the Russia of today, is a fact of incalculable importance to the future fate of the world. An ignorance of history inviting its fabrications by the unscrupulous cannot be regarded simply as an innocuous academic failure. It has affected all our lives. It has led directly to Belsen and Buchenwald and Katyn Wood. It has contributed its full share to two major European disasters.

Our knowledge of any past event is always incomplete, probably inaccurate, beclouded by ambivalent evidence and biased historians, and perhaps distorted by our own patriotic or religious partisanship. “Most history is guessing, and the rest is prejudice.

Centuries ago human knowledge increased slowly, so politics and economics changed at a leisurely pace too. Today our knowledge is increasing at breakneck speed, and theoretically we should understand the world better and better. But the very opposite is happening. Our new-found knowledge leads to faster economic, social and political changes; in an attempt to understand what is happening, we accelerate the accumulation of knowledge, which leads only to faster and greater upheavals. Consequently we are less and less able to make sense of the present or forecast the future. In 1016 it was relatively easy to predict how Europe would look in 1050. Sure, dynasties might fall, unknown raiders might invade, and natural disasters might strike; yet it was clear that in 1050 Europe would still be ruled by kings and priests, that it would be an agricultural society, that most of its inhabitants would be peasants, and that it would continue to suffer greatly from famines, plagues and wars. In contrast, in 2016 we have no idea how Europe will look in 2050. We cannot say what kind of political system it will have, how its job market will be structured, or even what kind of bodies its inhabitants will possess.

I can't believe that," said Seldon. "I should think that new copies would be made of any record in danger of withering. How could you let knowledge disappear?" "Undesired knowledge is useless knowledge," said Dors. "Can you imagine all the time, effort, and energy expended in a continual refurbishing of unused data? And that wastage would grow steadily more extreme with time.

Those who don't know history are doomed to repeat it

The careful study of history is of high value - among other reasons because it may instruct us, sometimes, concerning ways to deal our present discontents. I do not mean simply hat history repeats itself, or repeats itself with variations - although there is something in that, and particularly in the history of revolutions on the French model, which devour their own children. I am suggesting, rather, that deficiency in historical perspective leads to the ruinous blunders of of ideologues, whom Burckhardt call "the terrible simplifiers," while sound historical may diminish the force of Hegel's aphorism that "we Learn from history that we learn nothing from history."

One is astonished in the study of history at the recurrence of the idea that evil must be forgotten, distorted, skimmed over. The difficulty, of course, with this philosophy is that history loses its value as an incentive and example; it paints perfect men and noble nations, but it does not tell the truth.

The historian, now witness, stumbling in the illusion that he will survive. Long enough to set the details down on parchment in the frail belief that truth is a worthwhile cause. That the tale will become a lesson heeded. Frail belief? Outright lie, a delusion of the worst sort. The lesson of history is that no one learns.

Historical knowledge does not need artificial protection. ... The truth about the past can only be established and strengthened by the clash of wisdom and absurdity. If absurdity is banned by the law, wisdom too is diminished.

What’s the point of history, if it has nothing to say to the present?