Twenty years ago—on November 25, 1994—Isaiah Berlin accepted the honorary degree of Doctor of Laws at the University of Toronto. He prepared the following “short credo” (as he called it in a letter to a friend) for the ceremony, at which it was read on his behalf.

“It was the best of times, it was the worst of times.” With these words Dickens began his famous novel A Tale of Two Cities. But this cannot, alas, be said about our own terrible century. Men have for millennia destroyed each other, but the deeds of Attila the Hun, Genghis Khan, Napoleon (who introduced mass killings in war), even the Armenian massacres, pale into insignificance before the Russian Revolution and its aftermath: the oppression, torture, murder which can be laid at the doors of Lenin, Stalin, Hitler, Mao, Pol Pot, and the systematic falsification of information which prevented knowledge of these horrors for years—these are unparalleled. They were not natural disasters, but preventable human crimes, and whatever those who believe in historical determinism may think, they could have been averted.

I speak with particular feeling, for I am a very old man, and I have lived through almost the entire century. My life has been peaceful and secure, and I feel almost ashamed of this in view of what has happened to so many other human beings. I am not a historian, and so I cannot speak with authority on the causes of these horrors. Yet perhaps I can try.

They were, in my view, not caused by the ordinary negative human sentiments, as Spinoza called them—fear, greed, tribal hatreds, jealousy, love of power—though of course these have played their wicked part. They have been caused, in our time, by ideas; or rather, by one particular idea. It is paradoxical that Karl Marx, who played down the importance of ideas in comparison with impersonal social and economic forces, should, by his writings, have caused the transformation of the twentieth century, both in the direction of what he wanted and, by reaction, against it. The German poet Heine, in one of his famous writings, told us not to underestimate the quiet philosopher sitting in his study; if Kant had not undone theology, he declared, Robespierre might not have cut off the head of the King of France.

He predicted that the armed disciples of the German philosophers—Fichte, Schelling, and the other fathers of German nationalism—would one day destroy the great monuments of Western Europe in a wave of fanatical destruction before which the French Revolution would seem child’s play. This may have been unfair to the German metaphysicians, yet Heine’s central idea seems to me valid: in a debased form, the Nazi ideology did have roots in German anti-Enlightenment thought. There are men who will kill and maim with a tranquil conscience under the influence of the words and writings of some of those who are certain that they know perfection can be reached.

Let me explain. If you are truly convinced that there is some solution to all human problems, that one can conceive an ideal…

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© The Isaiah Berlin Literary Trust 2014