Over the centuries all sorts of thinkers have commented on the importance of knowing history. Here are a few quotes that I thought were particularly apt:
"If you would understand anything, observe its beginning and its development." --Aristotle
"This I regard as history's highest function, to let no worthy action be uncommemorated, and to hold out the reprobation of posterity as a terror to evil words and deeds." --Tacitus
"Whoever wishes to foresee the future must consult the past; for human events ever resemble those of preceding times. This arises from the fact that they are produced by men who ever have been, and ever shall be, animated by the same passions, and thus they necessarily have the same results."--Machiavelli
"History is philosophy teaching by example and also by warning." --Lord Bolingbroke
"History, by appraising. ..[the students] of the past, will enable them to judge of the future."
"In history, a great volume is unrolled for our instruction, drawing the materials of future wisdom from the past errors and infirmities of mankind." --Edmund Burke
"Life must be lived forward, but it can only be understood backward." --Søren Kierkegaard
"[History] may be called, more generally still, the Message, verbal or written, which all Mankind delivers to everyman." --Thomas Carlyle
"We can be almost certain of being wrong about the future, if we are wrong about the past." --G. K. Chesterton
"History is that which has happened and that which goes on happening in time. But also it is the stratified record upon which we set our feet, the ground beneath us; and the deeper the roots of our being go down into the layers that lie below and beyond the ... confines of our ego, yet at the same time feed and condition it, ... the heavier is our life with thought and the weightier is the soul of our flesh." --Thomas Mann
"A country without a memory is a country of madmen." --George Santayana
"History is, in its essentials, the science of change. It knows and it teaches that it is impossible to find two events that are ever exactly alike, because the conditions from which they spring are never identical." --Marc Bloch
"History cannot give us a program for the future, but it can give us a fuller understanding of ourselves, and of our common humanity, so that we can better face the future." --Robert Penn Warren
"What else can history teach us? Only the vanity of believing we can impose our theories on history. Any philosophy which asserts that human experience repeats itself is ineffectual."