Isaiah Berlin was one of the most remarkable men of his time, and one of the leading liberal thinkers of the century. Philosopher, political theorist, historian of ideas; Russian, Englishman, Jew; essayist, critic, teacher; he was a man of formidable intellectual power with a rare gift for understanding a wide range of human motives, hopes and fears, and a prodigiously energetic capacity for enjoyment – of life, of people in all their variety, of their ideas and idiosyncrasies, of literature, of music, of art.

His defence and refinement of what he saw as the most essential conception of freedom has achieved classic status, and the presence and character of this conception in the modern mind is due in no small measure to him. He also identified and developed, with considerable originality, a pluralist view of ultimate human ideals that supports his liberal stance, and deserves to become just as deeply embedded in our outlook.

In contrast to the great majority of ideologies and creeds, he argued that not all values can be jointly realised in one life, or in a single society or period of history, and that many ideals cannot even be compared on a common scale; so that there can be no single objective ranking of ends, no uniquely right set of principles by which to live.

From this it follows not only that people should be free (within the crucial but rather broad limits set by the demands of sheer humanity), both individually and collectively, to adopt their own guiding priorities and visions of life; but also, perhaps more radically, that a perfect, frictionless society, as well as being impossible in practice, is in principle incoherent as an ideal. Insights of this kind may seem unstartling to some today, but this, Berlin maintained, is a more recent, less widespread and less secure development than might be supposed; it is also a beneficent one, and may be laid partly at his door.

Like other great men he was a catalyst of excellence. Those who have had the good fortune to know him can testify to the strikingly positive, enlarging, warming experience of being in his company and listening to his irrepressible flow of captivating talk. He was legendary as a talker both for his imitable rapid, syllable-swallowing diction and for his inimitable range – he was astonishingly widely read in a number of languages, he knew (and deeply influenced) a great many prominent men and women in England and elsewhere, and he peppered his conversation and writings with a bewildering cascade of names. (This was not name-dropping: the names were a shorthand for their bearers’ ideas.)

Though he spent his whole professional life, apart from his war service, as an Oxford academic, he did not suffer from parochialism, and moved with equal ease in the many worlds he inhabited, often simultaneously, surviving day after day, without flagging, a punishing schedule of commitments and diversions. He lectured to learned and distinguished audiences in many countries, talked to undergraduate societies (not only in Oxford), colleges of education and sixth forms, and gave generously of his time to the growing number of those who made demands on it: former students with problems, scholars studying his work, strangers who sought his advice or help in connection with projects of their own.

He was often heard on the radio, especially the Third Programme, and gave numerous interviews, particularly to foreign journalists. He positively relished what others would have found intolerable pressures and, though he was perfectly serious when the occasion demanded, brought a sometimes impish sense of fun to everything that he undertook.

He was not, and would not have wished to be, any kind of saint, but he had in abundance what he called in others “moral charm”. This quality was particularly striking in his manner of conversation, which could unsettle those new to it. He did not stick to the point, but would sit back, look up, and follow his interest where it led, happily digressing, digressing from digressions, and unceremoniously returning to the topic of his own previous remarks, or changing the subject, apparently oblivious of what his interlocutor may have been saying, even at some length, in the interim.

This last idiosyncrasy might have seemed impolite in other hands, but in him it was clearly unselfconscious, and demonstrated his absorption in the issue before his mind, which he would pursue almost playfully, often in odd directions. Although talking to him made one’s mind race, it could be infuriating if one wanted to sort out some problem and come to a clear conclusion, and he was not always an attentive listener – sometimes because he had a shrewd idea of what one was going to say before one had said it.

He had no taste for purely verbal wordplay, but his wit, in the wider sense, was matchless. He could be bewilderingly quick on the uptake, and equally quick with an illuminating response. He was refreshingly direct and, for a man of his generation, unusually open: he made the obsessive circumspection of some parts of the Oxford establishment seem mean and life-denying by comparison. Gossip and anecdote abounded, but not malevolently: indeed, he was virtually incapable of innuendo, and did not seek to score points. Even when he propounded an unfavourable view of someone, it could seem more like a move in a game than a damning judgement.

He loved ranking people, and sorting them into types: most famously, hedgehogs and foxes – those in the grip of a single, all-embracing vision as against those who are more receptive to variousness. Indeed, his taste for light-hearted categorisation was an informal manifestation of his ability to extract and display the essence of a person or a difficult writer.

As a lecturer he had complete command of his material, and was spellbinding to listen to (fortunately several of his lectures were recorded, and can be heard at the National Sound Archive). He was consciously but not self-consciously Jewish, and a lifelong Zionist: his views counted for a good deal in Israel. He was a director of Covent Garden and a devoted opera-goer; he was a trustee of the National Gallery. He did not lack recognition – a knighthood, the OM, many honorary doctorates, the Mellon Lectureship, the presidency of the British Academy, the Jerusalem, Erasmus, Agnelli and Lippincott prizes – but always protested that he was being given more than his due, that his achievements had been systematically overestimated. He was larger than life, entirely sui generis, a phenomenon, irreplaceable.

Isaiah Berlin was born in 1909 to Russian-speaking Jewish parents in Riga, the capital of Latvia. His father, Mendel, owned a timber business (chiefly providing sleepers for the Russian railways); he and his wife Marie were lively, cultured people, enthusiastically interested in the arts. They bequeathed their enthusiasm in full measure to their only surviving child, whose love of music in particular, especially but by no means only opera, was a thread of deep and growing importance to him which ran through his life from boyhood onwards.

The Oxford don addressing a meeting in 1959 (Getty)

In 1915 the German army was closing on Riga, and the Berlins moved to Russia. They lived first in Andreapol, then, from 1917, in Petrograd, where in that year Isaiah witnessed both the Social-Democratic and the Bolshevik revolutions. On one occasion he saw a terrified, white-faced man being dragged and kicked through the streets by a mob; this was a formative experience which left him with an ineradicable loathing of any form of violence. In 1920 the Berlins returned to Latvia, under a treaty with the communists, and Mendel decided to move to England, where he had friends and business connections.

Arriving in early 1921, they lived first in Surbiton, then in London, in Kensington. After prep school Isaiah went to St Paul’s and, without ever losing touch with his Russian or Jewish identities, continued a thoroughgoing process of Anglicisation that enabled him to become a prominent figure in the English culture of his day.

In 1928 he went up as a scholar to Corpus Christi College, Oxford. He took Firsts in Greats and PPE in 1931 and 1932. Thereafter he was interviewed (unsuccessfully) for The Manchester Guardian and started to read for the Bar; but Richard Crossman, then a don at New College, gave him his first post, as a lecturer in philosophy. Almost immediately he was also elected to a fellowship at All Souls which ran concurrently with his lectureship until 1938, when he became a Fellow of New College. It was during this first spell at All Souls that he wrote his brilliant biographical study of Marx (Karl Marx: His Life and Environment, 1939) for the Home University Library: ironically he was by no means the editors’ first choice for the job.

During the early years of the Second World War, Berlin continued to teach. Then, in 1941, he was sent to New York by the Ministry of Information. In 1942 he was transferred to the Foreign Office, which he served until 1946 (apart from a few months in Moscow) at the British embassy in Washington as head of a team charged with reporting the changing political mood of the United States. The despatches sent to Whitehall from Washington, not in his name but mostly drafted by him, attracted the attention of Winston Churchill, and have long had a reputation for their brilliance; a selection was published (as Washington Despatches 1941-1945, edited by HG Nicholas) in 1981.

Berlin has written most engagingly about aspects of these years: in particular, his descriptions of his meetings in Russia with Boris Pasternak, Anna Akhmatova and other writers are extremely moving. His encounter with Anna Akhmatova had an especially profound effect on him; and the many passages about him in Akhmatova’s poems bear witness to its fundamental significance for her. “He will not be a beloved husband to me / But what we accomplish, he and I, / Will disturb the Twentieth Century”: she was convinced that there was a direct link between Stalin’s reaction to their meeting in 1945 and the beginning of the Cold War in 1946.

By the end of the war Berlin had decided that he wanted to give up philosophy for the history of ideas, “a field in which one could hope to know more at the end of one’s life than when one had begun”. In 1950, with this in view, he returned to All Souls, where in 1957 he was elected to the Chichele chair of Social and Political Theory in succession to GDH Cole. His inaugural lecture, “Two Concepts of Liberty”, is his best-known and most influential work, in which with great passion and subtlety he stands up for “negative” liberty – freedom from obstruction by others, freedom to follow one’s own choices – and shows how easily “positive” liberty, the (desirable) freedom of self-mastery, is perverted into the “freedom” to achieve “self-realisation” according to criteria laid down and often forcibly imposed by self-appointed arbiters of the true ends of human life.

One of the most attractive characteristics of Berlin’s writing is that he is never merely the detached scholar (Getty)

His account has remained an indispensable reference point for thought about freedom ever since, and permeates all informed discussion of the subject; nevertheless, perhaps partly because of the unassertive and deliberately unsystematic nature of his ideas, and his rejection of panaceas of any kind, he did not (to his relief) in any narrow sense acquire disciples or found a school of thought.

The year before his election to the chair, abandoning his apparently settled bachelor existence, he had married Aline Halban (daughter of the eminent European banker Pierre de Gunzbourg), perfectly described by Lord Goodman as “a lady of grace and distinction”. In his late forties he had found the partner who would be the linchpin of his life from that time onwards; and, in his three stepsons (he had no children of his own), a mutually devoted family. He always recommended marriage to others.

In 1966 Berlin became the first president of the newly founded Oxford graduate college, Wolfson, relinquishing his professorship the following year. Wolfson College, where he remained until his “retirement” in 1975, came into existence in its present form and under its present name (it began as Iffley College) only as a result of his efficacy as fund-raiser and charismatic inspirer of new institutional forms, traditions and loyalties. The generosity of the Wolfson and Ford Foundations in funding the building and endowment of the college was in direct response to his personal involvement.

Wolfson apart, Berlin’s chief legacy to the future is what he wrote: a large, enormously varied oeuvre of unmistakable style and penetration. In his own, reasonable, estimation his most important work is represented by his exploration of four fields of enquiry: liberalism; pluralism; 19th-century Russian thought; and the origins and development of the Romantic movement. Under all these headings he shed much new light, and the way he did so still retains the power to excite which it had when his contributions were first made public.

For most of his life his reputation as a writer lagged behind his actual output, much of which was in the form of occasional essays (“I am like a taxi: I have to be hailed”), often published obscurely. Comparatively little had appeared in book form – principally Karl Marx, The Hedgehog and the Fox (1953, a long essay on Tolstoy’s view of history) and the collection Four Essays on Liberty (1969), which included his inaugural lecture. But then in 1976 came Vico and Herder, and shortly thereafter four volumes of collected essays (1978-80).

These books gave the lie to a remark made by his friend Maurice Bowra when Berlin was appointed to the Order of Merit in 1971: “Though like Our Lord and Socrates he does not publish much, he thinks and says a great deal and has had an enormous influence on our times.” Other volumes followed in the 1990s, including two devoted to work he had left unpublished when it was first written, and, in February this year, The Proper Study of Mankind, a retrospective anthology of his best work.

By contrast with Bowra’s case, a good deal of Berlin’s way of speaking is captured, happily, in his published work, which is imbued with his personality and sets forth his cardinal intellectual preoccupations with the greatest clarity and fecundity, if often through the medium of his enquiries into the ideas of others.

One of the most attractive characteristics of his writing is that he is never merely the detached scholar, never forgetful that the point of the enquiry, in the end, is to increase understanding and moral insight. Since, as another friend, Noel Annan, has put it, “He will always use two words where one will not do”, his message – a notion he would have hated – is impossible to summarise without losing all of its characteristic mode of expression. But its central content can be baldly stated.

Berlin once described the main burden of his work as “distrust of all claims to the possession of incorrigible knowledge about issues of fact or principle in any sphere of human behaviour”. His most fundamental conviction, which he applauded when he discerned it in the writings of others, and adopted in an enriched form as his own, was that there can never be any single, universal, final, complete, demonstrable answer to the most ultimate moral question of all: how should men live? This he presents as a denial of one of the oldest and most dominant assumptions of western thought, expressed in its most uncompromising form in the 18th century under the banner of the French Enlightenment.

Contrary to the Enlightenment vision of an eventual orderly and untroubled synthesis of all objectives and aspirations, Berlin insisted that there exists an indefinite number of competing and often irreconcilable ultimate values and ideals between which each of us often has to make a choice – a choice which, precisely because it cannot be given a conclusive rational justification, must not be forced on others, however committed we may be to it ourselves. “Life may be seen through many windows, none of them necessarily clear or opaque, less or more distorting than any of the others.”

Each individual, each culture, each nation, each historical period has its own goals and standards, and these cannot be combined, practically or theoretically, into a single coherent overarching system in which all ends are fully realised without loss, compromise or clashes. The same tension exists within each individual consciousness. More equality may mean less excellence, or less liberty; justice may obstruct mercy; honesty may exclude kindness; self-knowledge may impair creativity or happiness, efficiency inhibit spontaneity. But these are not temporary local difficulties: they are general, indelible and sometimes tragic features of the moral landscape; tragedy, indeed, far from being the result of avoidable error, is an endemic feature of the human condition. Instead of a splendid synthesis there must be a permanent, at times painful, piecemeal process of untidy trade-offs and careful balancings of contradictory claims.

Intimately connected with this pluralist thesis – sometimes mistaken for relativism, which he rejected, and which is in fact quite distinct – is a belief in freedom from interference, especially by those who think they know better, that they can choose for us in a more enlightened way than we can choose for ourselves.

Berlin’s pluralism justifies his deep-seated rejection of coercion and manipulation by authoritarians and totalitarians of all kinds: communists, fascists, bureaucrats, missionaries, terrorists, revolutionaries and all other despots, levellers, systematisers or purveyors of “organised happiness”. Like one of his heroes, the Russian thinker Alexander Herzen, many of whose characteristics he manifested himself, Berlin had a horror of the sacrifices that have been exacted in the name of utopian ideals due to be realised at some unspecifiable point in the distant future: real people should not have to suffer and die today for the sake of a chimera of eventual universal bliss.

Berlin always discussed these ideas in terms of specific individuals, not in the abstract, remembering that it is the impact of ideas on people’s lives that give them their point. Here he was served by his unusual capacity for imaginative identification with people whose visions of life varied greatly and were often distant from his own. This enabled him to write rich and convincing accounts of a wide range of figures, historical and contemporary: Belinsky, Hamann, Herder, Herzen, Machiavelli, Maistre, Tolstoy, Turgenev, Vico; Churchill, Namier, Roosevelt, Weizmann; and many others.

His descriptions of those with whom he is in the closest sympathy often have a marked autobiographical resonance: he said of others, with dazzling virtuosity, what he would not have been willing to say of himself, what he probably did not believe of himself, though his words sometimes fit him precisely. Had he been sufficiently interested in his life and opinions for their own sakes, he would have been his own ideal biographer; but he would also have been a different man.

Isaiah Berlin was often described, especially in his old age, by means of superlatives: the world’s greatest talker, the century’s most inspired reader, one of the finest minds of our time – even, indeed, a genius. It may be too early to be sure about such strong claims. But there is no doubt that he showed in more than one direction the unexpectedly large possibilities open to us at the top end of the range of human potential, and the power of the wisely directed intellect to illuminate, without undue solemnity or needless obscurity, the ultimate moral questions that face mankind.