The Oxford philosopher Derek Parfit died on New Year’s Day. He was one of the leading thinkers of his generation, yet his death was not widely reported outside the obituary pages of the broadsheets. The contrast with the response to John Berger’s death the following day is striking. Soon after Berger died, a number of pieces appeared on the Guardian and New Statesman websites, and there were tributes on the BBC’s News at Ten, Newsnight and Today programmes.

Parfit was an outstanding philosopher. However, few people outside academic philosophy could name one of his books. Perhaps more telling, how many could name any British academic philosopher?

It has not always been like this. The reaction could hardly have been more different when another leading Oxford philosopher, Isaiah Berlin, died in November 1997. BBC2 showed two hour-long programmes about him on consecutive days, and Radio 3 broadcast a two-and-a-half-hour tribute the following month. Berlin’s death was reported on the front page of the New York Times and memorial services were held in three countries. In less than two decades something fundamental has changed. Has academic philosophy lost its place in mainstream British culture? If so, who is to blame? Is it the fault of academic philosophers themselves, or the media, or are there other changes going on in British culture?

Not so long ago philosophers such as Berlin, A J “Freddie” Ayer, Bernard Williams and Anthony Quinton were well-known public figures and received due recognition. Berlin was knighted in 1957, Ayer in 1970, Williams in 1999. The dates are significant. These years, from the 1950s to the 1990s, mark a golden age of British academic philosophy in mainstream culture.

Throughout the period, leading philosophers chaired important public inquiries and commissions. In the early 1980s Mary Warnock chaired the official committee on human fertilisation and embryology: her report led to the Human Fertilisation and Embryology Act 1990. She also chaired an inquiry into special needs education (1974-78), sat on a royal commission on environmental pollution (1979-84), chaired a Home Office committee on animal experimentation (1984-89) and later served as a member of the government advisory panel on spoliation of artefacts in the Nazi era.

Bernard Williams, too, served on several royal commissions and government committees: on public schools (1965-70), recreational drug abuse (1971), gambling (1976-78), obscenity and film censorship (1977-79) and social justice (1993-94). “I did all the major vices,” he said. But what put philosophers on the map was media coverage on radio and television. Leading philosophers often appeared on Start the Week and Desert Island Discs. Quinton became well known as a presenter of the long-running Round Britain Quiz. Berlin became a household name with his talks on everything from “freedom and its betrayal” to 19th-century Russian thought and literature.

From the 1960s onwards, it was television that brought leading philosophers into our living rooms. In 1978 the BBC broadcast 15 hour-long interviews with leading philosophers called Men of Ideas. Bryan Magee interviewed the likes of Berlin, Ayer and Noam Chomsky. Edited versions were published each week in the Listener magazine. In 1987 the BBC showed another 15-part series on philosophy, this one called The Great Philosophers, in which Bryan Magee interviewed prominent contemporary thinkers about the great philosophers, from Plato and Aristotle to Ludwig Wittgenstein.

Channel 4’s Voices featured debates about philosophy in the early 1980s. There was a series of six encounters with the fast-talking American John Searle, covering topics from artificial intelligence to French theory. And in the 1990s The Late Show on BBC2 frequently featured philosophy, with programmes devoted to Berlin and Michel Foucault, a tribute to Karl Popper, and appearances by thinkers such as Ray Monk, the author of a celebrated biography of Wittgenstein, as well as Mary Midgley.

However, it wasn’t just late-night discussions featuring talking heads. Philosophy appeared in other areas, too. There was TV drama, from Jonathan Miller’s mid-1960s adaptations of Plato The Drinking Party and The Death of Socrates to Tom Stoppard’s play Professional Foul, about a Cambridge philosopher visiting Prague during the Cold War. The Imitation Game by Ian McEwan introduced many viewers to the ideas of Alan Turing, and Michael Ignatieff’s Dialogue in the Dark was based on a conversation between James Boswell and the philosopher David Hume weeks before the latter’s death. On the BBC, Monty Python’s Flying Circus carried knowing sketches about Jean-Paul Sartre, Karl Marx taking part in a game show, and a football match between Greek and German thinkers. There was a sense of connection between television and the university common room.

Today this seems like something from a bygone age. According to David Edmonds, the editor of the recently published essay collection Philosophers Take on the World (Oxford University Press): “The idea that you would now commission someone to interview Freddie Ayer in an armchair for 45 minutes with no sound effects, no cutaways, is almost inconceivable.”

It is true you can hear Melvyn Bragg’s In Our Time, which, over almost 20 years, has addressed subjects from “language and the mind” and Erasmus to logical positivism and phenomenology. Or there is The Public Philosopher with Michael Sandel and The Philosopher’s Arms with Matthew Sweet. However, these are confined to Radio 4, and other than Alain de Botton’s miniseries Philosophy: a Guide to Happiness, for Channel 4, philosophy has vanished from mainstream television.

Naturally, some of the older programmes were very blokey: middle-aged men talking round a table. Both Men of Ideas and The Great Philosophers included only one woman in 15 episodes each – Iris Murdoch in the former and Martha Nussbaum in the latter. The shows could also be very patrician. Philosophers such as Stuart Hampshire (Repton and Balliol) and Ayer (Eton and Christ Church) sounded posh. If you watch Conversations for Tomorrow, a BBC production from the 1960s, you find J B Priestley talking to Berlin and Ayer, all three smoking cigars and drinking port. Through the smoke come voices that sound like something from Edwardian times.

David Edmonds sees the change in tone as “part of the end of deference . . . these great figures like Isaiah Berlin telling you what to think”. He links it with Michael Gove’s infamous distrust of experts. “In some ways it’s democratising. We somehow think we have a right to express ourselves that we didn’t have forty years ago. The stranglehold these great figures had over us has vanished, for good or ill.”

It’s not just philosophy’s relationship with television that has changed. In 1970 Fontana started publishing its Modern Masters series, a popular set of introductions to great thinkers and cultural figures. Philosophers played a crucial role. The series included guides to the work of Wittgenstein and Popper, Bertrand Russell, Martin Heidegger and Friedrich Nietzsche. Notable philosophers of the day contributed: Ayer on Russell, Richard Wollheim on Sigmund Freud, David Pears on Wittgenstein. In the 1990s there were acclaimed biographies of Isaiah Berlin by Michael Ignatieff, of Wittgenstein and Russell by Ray Monk and of Ayer by Ben Rogers. Most successful of all was Wittgenstein’s Poker (2001), by David Edmonds and John Eidinow, which has sold more than 200,000 copies worldwide.

Today, according to Ray Monk, the situation is very different. “Fewer philosophy books are published,” he says, “because of the RAE [Research Assessment Exercise].” The RAE set out to evaluate the quality of research undertaken by British institutions of higher education. As a result, Monk observes, academics would rather produce articles for eminent, peer-reviewed journals than spend years writing a biography. “Academics don’t make their reputations with books any more, but with articles,” he says. This has led to “the increased professionalisation of every academic discipline, including philosophy”.

Monk spent ten years writing his biography of Russell; he couldn’t have combined that with writing refereed articles for academic journals. He argues that, as a result, whereas in the 1950s it was the big names that counted, today’s philosophical ­debates are more issue-driven – consider “the trolley problem”, otherwise known as “Would You Kill the Fat Man?”. (A runaway trolley will kill five people or, if you pull a lever and divert it, one person. What do you do?)

“In the past,” Monk says, “you had Richard Ellmann on Joyce or Oscar Wilde; Michael Holroyd on George Bernard Shaw. Publishers can no longer hand out big advances [for such books], because publishing has become so precarious. And on the other hand, universities want articles, not biographies.” Consequently, many of the most successful authors in philosophy today are not academics but freelance writers, such as Alain de Botton and the NS’s John Gray.

What about newspapers? Again, Monk is pessimistic. “There is something seriously wrong with the press. The lack of coverage of Derek Parfit’s death tells us more about the state of the press than it does about philosophy.” In the increasingly desperate search for advertisers, articles about academic philosophy don’t pay their way.

Academic philosophy, by contrast, is in a good state. When Monk started teaching at the University of Southampton in 1992 there were nine members of the faculty. Today there are nearer 20 and, he says, “We attract more students than ever before.” At Oxford there are more than 180 members of the philosophy faculty. Increasingly, leading schools teach philosophy at A-level.

John Gray is more critical. “No intelligent general reader follows academic philosophy today,” he argues. He points to the huge changes that have transformed the subject’s status. First, he says, there was the Second World War. “As a result of the war, philosophers like Berlin, Hampshire and H L A Hart had a much larger experience of the world that involved making difficult choices and gave them what Berlin called ‘a sense of reality’.” Hampshire had interrogated Nazi war criminals and Hart worked at Bletchley Park. “They were brought close to moral and political realities in a way that subsequent generations were not.”

Second, Gray says, there has been a shift in “the social position of academics, especially academic philosophers. A previous generation had contact with leading ­figures in the worlds of culture and politics . . . That’s gone today. Academics have become marginal.”

This relates to his third point. “Academic life has become more professionalised. They write for each other, not for the general reader. Academic political philosophy ­today, for example, has zero influence on the practice of politics.” In the 1980s it was said that Margaret Thatcher was interested in Popper, Friedrich Hayek and Michael Oakeshott. “I doubt now,” says Gray, “whether any politician could name a leading academic philosopher. No one would know who they were.”

Edmonds agrees that there is a narrowing of the discipline. “People tend to ­specialise in very particular areas of philosophy. The way to make progress is to pick your area within a small part of philosophy.” He contrasts this with the recent past. “The Vienna Circle, Wittgenstein and Freddie Ayer, were arrogant enough to think they could transform philosophy. Philosophers are not that grandly ambitious any more.”

However, while the mainstream media may be giving up on philosophers there is a new player in town: social media is ­filling some of the gaps. Edmonds co-runs Philosophy Bites, a podcast that has had more than 30 million downloads since it started. The BBC may not rerun Michael Ignatieff’s interviews with Isaiah Berlin but you can find them on YouTube. Then, of course, there is Twitter. Alain de Botton currently has 639,000 followers; Daniel Dennett has almost 200,000.

Since his breakthrough book, How Proust Can Change Your Life (1997), de Botton has written The Art of Travel and The Architecture of Happiness, among others, and presented the television documentaries The Perfect Home and Status Anxiety. We are a long way from consequentialism and the self-interest theory of rationality in Derek Parfit’s great book Reasons and Persons.

Dennett, Gray and Peter Singer, all popular writers, represent very different areas of philosophy from de Botton’s. Dennett is renowned for his work on consciousness, Darwinism and atheism. Singer has written polemical books on animal rights, effective altruism and “rethinking life and death”. Gray, as well as contributing to the NS, has written books on al-Qaeda, the quest for immortality and “the delusions of global capitalism”. All of these authors reach large audiences, both with their books and online, by addressing topical subjects that matter to people. Their work takes us a long way from the ivory tower and common room.

Such thinkers are public intellectuals and they address the concerns of the broad society. But what is striking is how few are based in British universities. They are either, like Gray, outside the academy, or, like Singer and Dennett, based overseas. Increasingly, when we think about public intellectuals, whether philosophers, or historians such as Andrew Roberts, Simon Schama and ­Niall Ferguson, or cultural critics such as the late Robert Hughes and John Berger, they fall into one of these two groups. A British-based academic who is also a public intellectual – say, the likes of Mary Beard – is increasingly an exception.

If you are an optimist there is no crisis. Philosophy departments are thriving; even if television isn’t covering philosophical debates Radio 4 is; and the internet offers every kind of philosophy, past and present. Publishers still offer a spectrum of philosophical books. If you are a cultural pessimist, however, the picture looks different. Postwar, we could watch the greatest philosophers of the time talking about the most fascinating ideas. They wanted to reach out to a broad audience and they spoke about vital questions with passion and vigour. It is a great loss not to have access on mainstream media to the best contemporary thinkers on the most pressing subjects of the day.

The response to Derek Parfit’s death is a symptom of changes in our universities, in the media and in the culture beyond. As a result, the border guards have changed. Once, BBC executives and the broadsheets decided who were the important philosophers and which questions mattered. They may have lost interest, but if you care about Parfit or the Fat Man, go to your local library or bookshop or follow debates online: be your own border guard and wear a black armband for an era that has passed.

David Herman was a producer of “Voices”, “The Late Show” and “Start the Week”