THE SENSE OF REALITY: Studies in Ideas and Their History. By Isaiah Berlin. Edited by Henry Hardy. Farrar, Straus & Giroux. 304 pp. $25

"Ideas do, at times, develop lives and powers of their own and, like Frankenstein’s monster, act in ways wholly unforeseen by their begetters." So writes Berlin, a fellow at All Souls College, Oxford, and, at 87, one of the world’s pre-eminent intellectuals. In this new collection of occasional essays, most of them written during the 1950s and ’60s, Berlin ponders the jagged paths sometimes cut by humane and rational ideas.

In "Kant as an Unfamiliar Source of Nationalism," Berlin discovers "a traceable line of influence" from Kant’s conception of human freedom to the rise of violent nationalism. The German philosopher J. G. Fichte (1762–1814) gave the first twist to Kant’s teaching that mature people choose to live by certain values because they know them to be rational and to apply to everyone. From this, Fichte reasoned that fully developed people create their own values based on what they perceive to be true. The second twist, also Fichte’s but absorbing the influence of J. G. Herder (1744–1803), was to say that, because individuals are shaped by their milieus, they cannot truly act except as part of a group, a nation, and finally a state. Thus did the German romantic thinkers transform Kant’s appeal to reason into an assertion of collective will, not anticipating how this idea could drive nationalist revolts and, eventually, genocidal slaughter.

Berlin’s explanation of how morally beneficial ideas become perverted leads him to conclude that human life is composed of unaccountable infinitesimals, a dark mass of factors that cannot be analyzed, only felt and lived. Absent an all-encompassing truth about reality, and given the vulnerability to fanaticism demonstrated in this century, he urges a conscious acceptance of plural versions of the truth. He admires reformers such as the Indian poet Rabindranath Tagore (1861-1941), who believed that the only hope for India was to combine English political freedoms with a nationalism rooted in Indian civilization.

Berlin excels at this kind of intellectual portraiture, but he is more than a portraitist. While adding to our store of knowledge about the history of ideas, he has also refocused our thinking. Nationalism, he has shown, is a legitimate expression of the human need for recognition and a degree of material security that, if ignored, explodes into terrible crimes. To accommodate that need, contemporary liberalism must include both protection of people’s liberties and a place for them to live satisfying lives as members of communities. Vintage though they are, these essays could hardly be more timely.

—Susan Ginsburg