Tailpieces of a flirtatious fox

Like his namesake city, Isaiah Berlin's oeuvre is a panorama of abrupt finitudes and historical incongruities. The Power of Ideas brings together some medium-sized Berliniana written between 1947 and 1996, the last full year of its author's life. Too brief to count as full-blown essays, longer than mere trifles, they are also more than occasional pieces. Henry Hardy, Berlin's tireless editor, has collected them from a wide range of sources, only one an anthology that Berlin himself published during his lifetime ( Concepts and Categories , the source of "The purpose of philosophy"). The others are prefaces, magazine articles, encyclopedia entries, radio talks and edited collections.

The Power of Ideas discloses a Berlin not different from the one we knew, but more than ever like himself. It provides a sample of his principal intellectual concerns: Israeli politics, the Enlightenment and scientific rationalism, Zionism, Russian intellectual history, pluralism and, of course, liberty. Its dramatis personae include Georgy Plekhanov, Friedrich Meinecke, Chaim Weizmann, Vissarion Belinsky, Alexander Herzen and Giambattista Vico.

Some of the more political material has withered in the interim, particularly the essays on Israel. Hardy bravely reprints Berlin's "The origins of Israel", a piece written in 1953 for the Anglo-Israel Association. He deploys a veritable mobile army of metaphors when describing the Jewish statelet: "Like Aaron's rod, this apparently dead entity, this artificial wooden object, hammered together in a haphazard manner under critical conditions and in terrible haste, has burst into green leaf." Its rude vitality is contrasted with the previous "relative vacuum of Palestine", which is explained by "the endemic feebleness of the Muslim culture in this corner of the Arab world". After Deir Yassin, the King David Hotel bomb and the activities of the Irgun militia, there were no longer grounds for such celebrations of the Israeli state.

Berlin's biographer, Michael Ignatieff, suggested that Berlin's Zionism was tempered, if on tactical rather than principled grounds, by his adoptive Britishness. But, in that false dismissal of the predecessor culture and the denial of displacement, it is hard not to see wilful self-delusion, a failing that Berlin is fond of exposing in others. At the end of "The search for status", he deplores as self-deceiving the attempt by reformers and revolutionaries to represent quite different values as a commitment to liberty. In the end, he notes, "we all pay too dearly for our wish to avert our gaze from such truths... for our desire to be deceived".

As a pillar of the Foreign Office and later All Souls College, Oxford, Berlin was familiar with the ambiguities of assimilation. In "Jewish slavery and emancipation", he rejected Arthur Koestler's suggestion that Jews should either return to Israel or assimilate, despite "the large amount of truth which (Koestler's proposal) embodies". Existing Zionism demanded some tortuous intellectual negotiations, however. Berlin put down the Jewish-British contretemps before Israel attained statehood to Ernest Bevin, who being working-class and illegitimate, was not comme il faut . Weizmann, on the other hand, hailed from a "Russian Jewish town" at "the heart of the diaspora". Berlin's oxymoron betrays strategic ambivalence: he was born in Riga, presumably at the diaspora's periphery. Neither truly of the diaspora nor a gentile, his view of his own identity was a matter of negative definition.

Similar elusiveness marks Berlin's philosophical work. His influence on contemporary liberalism remains pronounced, mainly through his invention of "value-pluralism", an idea that he claimed to discern in the writings of some of his heroes, such as Herder and Vico. Berlin's celebration of bricolage is well represented. "My intellectual path" sets out his position on pluralism, or the position he had reached by the end of his life. Pluralism is not relativism, since values were not mere projections of individual preference; on the other hand, there is a finite number of these values, since there are limits on what human beings can intelligibly pursue.

Berlin adds that although Nazi values may be "detestable", they are still, apparently, values. But it is not clear why we should say that they are values, rather than just beliefs about values. This is made more baffling by the fact that Berlin was happy to claim that values have objective status. One of the advantages of this view is that it allows us to dismiss certain claims about value, such as Nazi ones, as merely wrong: there are objective truths, or facts, and these values fail to represent them. But if they are merely wrong, then they are not values at all.

If values are objective, beliefs about them cannot be like other artefacts thrown up by alien cultures. For to identify a cultural artefact as a value is, on Berlin's objectivist view, not merely to say that in fact it does guide action, but to say that it justifiably does so. It may be a fact about the Yoruba or the Azande that they go on in such-and-such a way, even if their way of going on follows from beliefs about value that are, as a matter of brute fact, bonkers. But if their beliefs about value are bonkers, there is nothing there to do the job of justifying their actions, which values do; there are only their false beliefs. In failing to see this, Berlin seems to have regarded values as exotica to be collected, rather than asking himself which values, if any, were the right ones. His attitude bears out the charge made by George Kateb that Berlin took a misguidedly aesthetic attitude towards moral beliefs. Easier to sustain would be a limited pluralism where certain genuine values conflict in a rationally interminable way with one another, rather than implying that all beliefs about value are, ipso facto , values.

Perhaps Berlin's most famous essay is "The hedgehog and the fox", a line that he took from Archilochus: the fox knows many things, the hedgehog knows one big thing. To which mammal was Berlin akin? The answer seems obvious: Michael Oakeshott called him "a very Paganini of ideas". Berlin's verdict on Vico ("one of the boldest innovators in the history of human thought") could be applied to Berlin himself: "His thought is a tangled forest of seminal ideas, recondite allusions and quotations... the ideas conflict and obscure each other, and although this communicates a kind of turbulent vitality to all that he writes, it does not make for lucidity."

This last charge of unclarity at least might be thought to miss the mark in Berlin's own case, but in fact the problems of understanding arise not when his assertions are taken individually, but when they are put together. The short essay "Liberty", first composed for radio broadcast in 1962 but recycled for inclusion in Ted Honderich's Encyclopaedia of Philosophy more than 30 years later, manages to compress into four short pages the conflations and aporias of "Two concepts of liberty", of which "The search for status" (1959), printed here for the first time, was the prototype. Those who go to it worrying whether "negative liberty" is about the rejection of paternalism, or of republican ideals of freedom, or of collective projects, or of interference in the private realm, are likely to end up worse off than when they set out.

As John Gray has argued, part of the perplexity results from Berlin's insistence, despite his pluralism, on the priority of liberty, and a specific interpretation of liberty at that. In "Liberty", Berlin argues that an advantage of "negative" liberty is that, unlike its "positive" counterpart, it does not pretend that paternalistic interference with individuals' actions is justified by "forcing them to be free". He flirts with incoherence: "negative" liberty recognises that liberty itself has no special value compared for example with the values that support paternalism, and this is why liberty has special value.

Berlin remains the pluralist aesthete glorifying in the riotous profusion of human culture, but the glorying can itself appear monomaniacal. His liberalism is continually embarrassed by his attachment to diversity. In the essay on Tolstoy, he argued that, his apparent foxiness notwithstanding, the author of Anna Karenina aspired to be a hedgehog. Berlin himself begins to look like a hedgehog with frustrated vulpine aspirations.

Glen Newey is reader in politics, Strathclyde University.