Professor Sir Bernard Williams will be remembered as the most brilliant and most important British moral philosopher of his time. But in his hands moral philosophy encompassed much more than might be expected, including political theory, metaphysics, the theory of knowledge, much history, as well as philosophy of mind, the nature of the self, and the nature of truth itself. Like Spinoza or Locke or Aristotle, Williams knew that any understanding of ourselves as agents in society required a detailed metaphysic and a detailed understanding of reason, objectivity and truth. From his first book Descartes (1978), which concerned that leading figure of the 17th-century scientific revolution, to his last book, Truth and Truthfulness (2002), written and published in the midst of his final illness, he effortlessly spanned the entire discipline of philosophy.

Nor did Williams shun public life. He served for almost 20 years on the board of English National Opera (and wrote with great insight and knowledge about music). He sat on royal commissions and government committees of inquiry. “I did all the major vices — gambling, drugs, pornography and public schools,” he said.

Most notably he chaired the Committee on Obscenity and Film Censorship and, having reconciled the views of members ranging from the psychotherapist Anthony Storr to the film critic of The Times, produced a report that took a permissive approach influenced by the thinking of John Stuart Mill; most of his proposals were introduced, though his ideas did not endear him to the Prime Minister, Margaret Thatcher.

Bernard Arthur Owen Williams was born in 1929, the only son of a civil servant, and was educated at Chigwell School in Essex and at Balliol College, Oxford. At Oxford he was singled out by the great Professor Eduard Fraenkel as a particularly promising classical scholar, but his interest had already turned to philosophy before he completed Greats, with a congratulatory First. Elected a Fellow of All Souls in 1951, he went as Fellow and Tutor in philosophy to New College immediately after his National Service in the RAF (he is supposed to have counted a year flying Spitfires as the happiest year of his life). His extraordinary talents had already declared themselves while he was still an undergraduate, when he was regularly asked for help by his contemporaries whenever they found some philosophical problem too much for them.

He moved from New College to University College London, as lecturer in philosophy in 1959. He was elected Professor of Philosophy at Bedford College, London, at the early age of 35, and he then moved to Cambridge and to King’s College as Knightbridge Professor of Moral Philosophy in 1967. After eleven years there he was elected to succeed Sir Edmund Leach as Provost of King’s College, where he stayed from 1979 to 1987. Like many other academics, he became disenchanted with the Thatcherite contempt for Britain’s universities, and accepted a prestigious professorship at Berkeley, only returning finally to take up the White’s Chair of Moral Philosophy at Oxford.

In moral philosophy Williams was an uncompromising critic of two of the major movements that often dominate the subject: utilitarianism and Kantianism. Utilitarianism is the doctrine that actions are to be judged solely by their consequences for human good or ill, however that may be measured. It has always had critics, and students are brought up to puzzle over whether it could be right to hang an innocent man if more good can be gained, or more harm averted, by doing so. But in his contribution to the 1973 work Utilitarianism, For and Against, Williams transformed the standard discussion by connecting the issue to the nature of motivation and the nature of agency. Williams analysed examples where an agent could maximise goods, or minimise harms, but only at the cost of performing actions that go deeply against the grain. He argued that we cannot coherently regard ourselves simply as conduits to greater general utility. What we do is more than what we produce. An agent’s integrity is bound up with a local sphere of responsibility, and it is the meaning of the actions performed inside that sphere that give us our identities. By trying to turn us into “servants of the world”, utilitarianism in fact destroys the very networks of responsibility that are required for life to have meaning at all. Williams’s point was not that utilitarianism necessarily gave the wrong answers in difficult cases, but the much more subtle one that it goes about getting its answers in the wrong way. His examples and his analysis dominated all subsequent work in this area, and were largely responsible for a general awareness of the complex clusters of values that actually determine our decision-making. The subsequent collection he edited with Amartya Sen, Utilitarianism and Beyond (1982), only accelerated the general flight from utilitarianism among many economists and philosophers.

Similarly, Williams’s opposition to Kantianism in ethics was founded on a deep, metaphysical, mistrust of the nature of agency as it is construed by Kantians. Williams had a genius for memorable phrasing, and the issue here is one of what he called moral luck. Kant sought to put right action beyond the sphere of happenstance and contingency. Whether you do right or wrong is entirely voluntary, totally within the control of your will. It does not matter what your emotional nature might be, nor your circumstances, nor the consequences that actually come about because of your action. This fantasy of pure freedom is part of what Williams called “the morality system”, a system of thinking about guilt and responsibility that still dominates many of our attitudes. Williams argues, like Hume, that motivation comes from passions rather than reason alone, and that the motivational forces to which agents are subject are never entirely within their control. He goes on to undermine the morality system by concentrating first upon the moral emotions of shame and remorse, and secondly upon the many ways in which luck determines whether anyone gets into situations in which those emotions are appropriate. Thus we might behave in exactly the same way on two different occasions, although in one of them we “get away with it”, whereas in the other, because of bad luck, catastrophe follows and remorse and shame dog our footsteps.

The morality system, Williams argued, can make no sense of this difference, since on each occasion we equally did what we judged right or did what we judged wrong. Yet the emotional difference cannot be ignored: life would be unrecognisable without it. So the moral emotions, properly understood, suggest that human life both is, and ought to be, conducted in terms of a much more pluralistic and heterogeneous set of values, which Williams preferred to dub “ethics” rather than “morals”. In the eyes of many, his discussion in works such as Ethics and the Limits of Philosophy (1987) or Shame and Necessity (1993), exploded the Kantian picture just as effectively and influentially as he had destroyed Utilitarianism. However, in the eyes of some critics the former book flirted with a more radical scepticism about the entire enterprise of ethics. The limits referred to in the title often seemed more like limits to the coherence of ethics itself, rather than limits to our philosophical understanding of what ethics is supposed to be.

Alongside his work in moral philosophy Williams did influential work on political theory, where an early paper on equality has been a constant landmark, and especially on personal identity, where he explored superbly the delusive role that imagination plays in generating some of our deepest-seated illusions about ourselves. We think we can imagine ourselves being Cleopatra or Napoleon, and this generates the illusion that the “I” can float free of its contingent embodiment, and therefore should be identified with something like a traditional soul. Williams pointed out, rightly, that what I call imagining myself being Napoleon is no more than imagining seeing things as Napoleon did — “images of, for instance, the desolation at Austerlitz, as viewed by me vaguely aware of my short stature, and my cockaded hat, my hand in my tunic”. It is akin to acting Napoleon. There is no supernatural self or soul that is transported in the imagining, so the imagining itself has no metaphysical weight. Inevitably Williams went on to make connections that most other philosophers would have missed, for instance with the difference between seeing a character in a play and seeing an actor, or with the intriguing fact that you can film a scene which is nevertheless presented as being unwitnessed. Much of this work is visible in his early collection Problems of the Self (1973).

While Williams’s brilliance as a critic was universally acknowledged, some commentators found it harder to know what positive system he intended to champion. Aristotle was clearly the primary influence, but Williams had a profound sense of the varieties of human existence, which prevented him from subscribing to any complacent view of a single human nature and a single proper expression of it. Aristotelians try to derive what it is to be a good human being simply from what it is to be a human being, just as once we know what a knife is, we know what a good knife is. But hearing a colleague comparing being a good action to being a good knife, Williams once dryly remarked that if a knife was bad enough it stopped being a knife altogether, whereas when someone does something really bad, they still do something. Similarly, whereas some of his stress on emotion in human affairs affiliated him to Hume, Williams could never accept a purely prescriptive or emotive theory of ethics. In many of his writings he explored the centrality of “thick concepts” (another coinage) in practical reasonings. A thick concept is used when we describe someone as modest, or just or courageous, in which there are both elements of description and elements of evaluation. Fact and value are seamlessly intertwined, so there is no need to employ the relatively abstract vocabulary of “good” or “bad”, “right” or “wrong”. This intertwining gives us a way of crossing, or ignoring, the distinction between fact and value that bedevils so much ethical theory. However, it does not mean that with such concepts we describe “what is there, anyway”, or give an absolutely true description of things such as science may aspire to deliver. Williams always emphasised the perspectival nature of ethical thought, looking for a way to reconcile that with a satisfying account of its authority and its centrality, and its claim to identify a subject about which knowledge is possible.

A similar perspectival and pluralistic attitude informed Williams’s discussion of yet another topic that he made his own, that of the nature of tragedy and tragic dilemmas, as when in Iphigenia, Agamemnon must either betray his army or murder his daughter. Williams again gave a central place to notions such as remorse and shame. But he also suggested that these examples set a limit to the goal of consistency in ethics. Whereas consistency is the first virtue of theory that purports to describe how things stand, in response to tragic dilemmas the inconsistency of thinking both that you must do something and that you cannot do it seems far from being a vice. Indeed, it seems to be a virtue, since not to think both things would seem to be crass and insensitive. Here too we have a contrast between an ethical response to the world and a description of its fabric.

In the latter part of his career Williams began to appreciate the polymorphous and often perverse writings of Friedrich Nietzsche, and he edited an edition of The Gay Science. His final book, Truth and Truthfulness, steers a course between what Williams called the deniers, or in other words sceptical and relativistic, anything-goes, irresponsible postmodernist descendants of Nietzsche, and more conservative philosophies of truth and objectivity. Williams offered a “genealogy” of truth, and of the virtues connected with truth such as sincerity and accuracy. Such a genealogy vindicates a notion if it can show how essential it is to anything recognisable as a human life, in which we are often given no option but to trust the testimony of others. Williams recognised, however, that many cultural and historical factors influence our capacity to see things one way or another, so the deniers had a point. The difficulty comes in appreciating it without exaggerating it, as postmodernists do, to the point of undermining reason, science, and logic altogether. Williams pointedly chose as an epigraph for this book a quotation from Proust: “I have always had a high regard for those who defend grammar or logic. One realises fifty years later that they have warded off great dangers.”

All worthwhile moral philosophers offer something of themselves in their work. Williams’s standpoint was above all generous and humane, pluralistic and sensitive. His dislike of highly abstract moral systems was the other side of a genuine absorption in human variety and the human carnival. He cast a fond eye over the foibles and quirks of humanity, and a compassionate eye on its tragedies and losses. Above all he exuded a sense of enjoyment. There is a rare zest in his writings, as much as there was in his life. He lit up any room. He would laugh the loudest, tell the best stories, attract the most attention. The pleasure he took in receiving an honorary doctorate from Cambridge last year was exceeded only by the hilarity around him during the otherwise dignified luncheon afterwards. He dazzled everyone who met him, and although his quicksilver mind often left colleagues floundering far behind, his endless open-mindedness and endless good humour deflected resentment. His first wife was Shirley Brittain Catlin, MP and Cabinet Minister. He is survived by his second wife, Patricia Law Skinner, a daughter from his first marriage and two sons from his second.

Professor Sir Bernard Williams, FBA, philosopher, was born on September 21, 1929. He died on holiday in Rome on June 10, 2003, aged 73.