Henry Hardy, a Fellow of Wolfson College, Oxford, is one of Isaiah Berlin's literary trustees. He has edited or co-edited many volumes by Berlin, including a four-volume edition of his letters.
Isaiah Berlin (1909-97) is one of the most important thinkers, and one of the most celebrated prose-writers, of the twentieth century. A plain-speaking connoisseur of human beings, he not only understands the human condition in the broadest sense, but also revels in the indispensable idiosyncratic details of our individual lives. His brilliant, timeless essays speak to any receptive and intelligent reader.
Berlin strongly believed in 'the power of ideas'. His own ideas, which often swim against the current of conventional thought, are increasingly relevant today. Growing globalisation, migration and interconectedness, far from being homogenising forces, uncover and exacerbate the ethical differences that divide humanity. They bring to centre stage just those issues of multiculturalism and mutual cultural toleration that Berlin illuminated.
Berlin is a staunch defender of the maximum possible freedom from political control, and of the widest practicable range of moral and cultural diversity, as against the authoritarianism and conformism to which societies are continuously vulnerable. His distinction between the 'monist' hedgehog (the single-issue fanatic) and the 'pluralist' fox (who welcomes variety and untidiness), and his celebration of 'the crooked timber of humanity', out of which 'no straight thing was ever made', have entered the vocabulary of modern culture.
Berlin's 'value pluralism' - the recognition that our deepest values are irreducibly multiple, not variations on a single overarching value such as happiness or utility, and may create clashes that cannot be resolved without tragic loss - is a view of morality with the power to transform lives, to turn missionaries into explorers, terrorists into diplomats. And the problems created by the plurality of value are endemic in human nature: each political authority and each individual has to face intractable conflicts of the kind that Berlin highlighted.
Berlin gives no comfort to fanatics. All inflexibly assertive ideologies, political or religious, are dangerous, and must be firmly resisted. The stand-off between extreme Islamic religious beliefs and Western liberalism is a paradigmatic case of conflict between monism and pluralism. How are we to regard or treat those who not only differ from us in their fundamental commitments, but insist that we are in the wrong, and sometimes try to force us to comply?
Berlin's response is clear. Fundamentalism, terrorism and aggressive nationalism are driven by mistaken but powerful ideas, just as Nazism and Communism were. The ideas may be cruder and less well articulated, but they are no less potent. They stem from ignorance and prejudice, propaganda and stereotypes, which should be combated by all available techniques of education: our enemies' enemy is knowledge.
The price of freedom, famously, is eternal vigilance. And the defence of freedom and complexity against their betrayers is a task that does not grow easier or less urgent. The same goes for our defence against all intellectual malignity. Our susceptibility to ideological error and manipulation is inbuilt, and Berlin is a trusty guide as we seek to understand and resist the illiberal forces that permanently threaten to blight our lives and poison the course of history.