Source: “Notes on Prejudice,” by Isaiah Berlin. The New York Review, October 18, 2001. ©The Isiah Berlin Literary Trust 2001.

Few things have done more harm than the belief on the part of individuals or groups (or tribes or states or nations or churches) that he or she or they are in sole possession of the truth: especially about how to live, what to be & do-and those who differ from them are not merely mistaken but wicked or mad & need restraining or suppressing. It is a terrible and dangerous arrogance to believe that you alone are right, have a magical eye which sees the truth and that others cannot be right if they disagree.

This makes one certain that there is one goal & one only for one’s nation or church or the whole of humanity, & that it is worth any amount of suffering (particularly on the part of other people) if only the goal is attained … the belief that there is one & only one true answer to the central questions which have agonized mankind & that one has it oneself-or one’s leader has it-was responsible for the oceans of blood, but no Kingdom of Love sprang from it-or could. There are many ways of living, believing, behaving; mere knowledge provided by history, anthropology, literature, art, law makes clear that the differences of cultures & characters are as deep as the similarities (which make men human) & that we are none the poorer for this rich variety; knowledge of it opens the windows of the mind (and soul) and makes people wiser, nicer, & more civilized; absence of it breeds irrational prejudice, hatreds, ghastly extermination of heretics and those who are different; if the two great wars plus Hitler’s genocides haven’t taught us that, we are incurable. …

Compromising with people with whom you don’t sympathize or altogether understand is indispensable to any decent society; nothing is more destructive than a happy sense of one’s own-or one’s nation’s-infallibility, which lets you destroy others with a quiet conscience because you are doing God’s (e.g. the Spanish Inquisition or the Ayatollas) or the superior race’s (e.g. Hitler) or History’s (e.g. Lenin-Stalin) work. …

Another source of avoidable conflict is stereotypes. Tribes hate neighboring tribes by whom they feel threatened & then rationalize their fears by representing them as wicked or informer, or absurd or despicable in some way….

All these stereotypes are substitutes for real knowledge-which is never of anything so simple or permanent as a particular generalized image of foreigners-and are stimuli to national self satisfaction & disdain of other nations. …

Nationalism … is the strongest & most dangerous force at large today. It is usually the product of a wound inflicted by one nation on the pride or territory of another. …

Conquest, enslavement of peoples, imperialism etc. are not fed just by greed or desire for glory, but have to justify themselves to themselves by some central idea: … the white man’s burden; communism; and the stereotypes of others as inferior or wicked. Only knowledge, carefully acquired & not by short cuts, can dispel this, even that won’t dispel human aggressiveness or dislike for the dissimilar (in skin, culture, religion) by itself. Still, education in history, anthropology, law (especially if they are “comparative” & not just of one’s own country as they usually are) helps.