The course of my intellectual life has been dominated by the attempt to come to terms with the Christianity I imbibed as a child. As an undergraduate at Oxford, where I was put off by the vigorously evangelical Oxford Inter-Collegiate Christian Union, what belief I retained in the formal doctrines of the church gradually left me; but I was not alone in finding that loss of belief preceded (by many years) emancipation from the power of religious conditioning. I felt guilty of unbelief; any rational input that weakened the power my religious upbringing had over me was devoutly to be embraced.
I had no idea when I joined Oxford's Wolfson College as a graduate student of philosophy in 1972 that I was about to discover not only an intellectual source of liberation from this power, but also my current occupation. The college's president was Isaiah Berlin. It was clear as soon as I met him (at a scholarship interview for which I arrived late after a car accident, and during which he repeatedly went to the window to see if a taxi had arrived) that he was a remarkable man; but I had never read any of his work, and knew next to nothing about him.
I asked someone where I should start, and was directed to Four Essays on Liberty, published three years earlier. I took it with me on a visit to a remote Exmoor cottage during a vacation and was transfixed. Berlin liked to refer to the unmistakable sensation of "sailing in first-class waters", and this was the sensation I experienced. Quite apart from the persuasiveness of the propositions contained in the book, here was obviously a man of rare insight into human nature, a man plentifully endowed with that "sense of reality" that he welcomed when he found it in others. There was room for disagreement on this or that point, but on the large issues one felt in safe hands.
The unifying idea of the book is Berlin's "value pluralism" (emphatically not the same as relativism, despite frequent misinterpretations). This is his belief that the values humans pursue are not only multiple but sometimes irreconcilable, and that this applies at the level of whole cultures - systems of value - as well as between the values of a particular culture or individual. Even if there is no strict logical contradiction between this pluralism and Christianity (could Jesus have been a pluralist?), there is certainly a strong temperamental incompatibility, and I have found no more effective antidote to an irrational religious hangover.
It is part of Christianity, as of the other great monistic religions, to claim there is one way to salvation, one right way to live, one true value-structure. This is the claim that, when it is given fanatical expression, leads to fundamentalism, persecution and intolerance. Pluralism is a prophylactic against such dangers. It is a source of liberalism and toleration - not just the unstable kind of toleration that waits for the mistaken to see the light, but the deep toleration that accepts and welcomes visions of life that differ irretrievably from those we ourselves live by.
Four Essays is full of other gold, including a devastating critique of historicism and determinism, the famous discussion of "positive" and "negative" freedom, and an examination of the tensions in the views of John Stuart Mill. It is one of the richest and most humane books I have ever read. Unfortunately it was also badly published - initially only in paperback, which was a premature experiment - but it has risen above this inauspicious start and become a classic, as it deserves. It was not part of its author's purpose to liberate his readers from religious belief or its after-effects, but any great book has unforeseen powers, and this was the power that worked in me when I needed it.
Henry Hardy, a supernumerary fellow of Wolfson College, Oxford, is editing the letters and unpublished papers of Isaiah Berlin, who died on November 5. This article was written before Berlin's death.