Bernard Henri Levy (left) and Jean Paul Sartre refuse to discuss matters at the Musée Grévin waxwork museum in Paris, France. Photo by Sylvain Sonnet/Hemis/Corbis

In 1913 the philosopher Ludwig Wittgenstein fled the interruptions and distractions of Cambridge to live as a hermit in Norway. No one knew him there, and he could focus on his work on logic in isolation. It worked. He lodged for a while with the postmaster in Skjolden, a remote village 200 miles north of the city of Bergen, and later had a hut built overlooking the fjord. Alone, he wrestled with the ideas that would metamorphose into his Tractatus Logico-Philosophicus (1921). Anyone who tried to pass the time of day with him got short shrift. ‘Go away! It’ll take me two weeks to get back to the point where I was before you interrupted me,’ he is supposed to have shouted at one local who made the mistake of greeting him as he stood pondering what could not be said. From Wittgenstein’s perspective, the year he spent in Norway was the source of much of his philosophical creativity, some of the most intense thinking this markedly intense philosopher achieved in his lifetime. While there, he did little more than think, walk, whistle, and suffer from depression.

Wittgenstein ensconced in his Norwegian ‘hut’ (really, a two-storey wooden house with a balcony) is for many the model of a philosopher at work. Here the solitary genius sought out isolation that mirrored the rigours of his own austere philosophy. No distractions. No human company. Just a laser-like mind thinking about first principles, as he stood surveying the fjord or strode through the snow. Wittgenstein had precedents. The sixth-century Boethius wrote his Consolation of Philosophy in a Roman prison cell, his mind focused by his imminent execution; Niccolò Machiavelli produced The Prince (1532) in exile on a quiet farm outside Florence; René Descartes wrote his Meditations on First Philosophy (1641) curled up next to a fire. Jean-Jacques Rousseau was happiest living in the middle of a forest, away from civilisation, and so on. Philosophy in its highest forms seems intently solitary and often damaged by the presence of others.

Yet this stereotype of the genius at work in complete isolation is misleading, even for Wittgenstein, Boethius, Machiavelli, Descartes, and Rousseau. Philosophy is an inherently social activity that thrives on the collision of viewpoints and rarely emerges from unchallenged interior monologue. A closer examination of Wittgenstein’s year in a Norwegian wood reveals his correspondence with the Cambridge philosophers Bertrand Russell and G E Moore. He even persuaded Moore to travel to Norway — an arduous train and boat trip in those days — and stay for a fortnight. The point of Moore’s visit was to discuss Wittgenstein’s new ideas about logic. In fact, ‘discussion’ turned out to mean that Wittgenstein (who was still technically an undergraduate) spoke, and Moore (who was far more eminent at the time) listened and took notes.

Yet Moore’s presence was somehow necessary for the birth of these ideas: Wittgenstein needed an audience, and an intelligent listener who could criticise and help him focus his thought, even if those criticisms weren’t uttered. And he wasn’t the only one who needed an audience. Boethius in his cell imagined his visitor: Philosophy personified as a tall woman wearing a dress with the letters Pi to Theta on it. She berates him for deserting her and the stoicism she preached. Boethius’s own book was a response to her challenge.

The smile in someone’s voice, a moment of impatience, a pause (of doubt perhaps?), or insight — these factors humanise philosophy

Machiavelli, meanwhile, was indeed exiled, cut off from the intrigues of court life, a city dweller forced into a bucolic existence against his will. But in a letter to his friend Francesco Vettori of 10 December 1513, he described how he spent his evenings: he would retire to his study and conjure up the great ancient thinkers and hold imaginary conversations with them about how best to govern. These imaginary conversations were the raw material for The Prince. Descartes might have locked himself away to write, and avoided distractions by doing most of his work lying in bed, but when he came to publish his Meditations it was with a number of critical comments from other philosophers, including Thomas Hobbes, together with his responses to their criticisms. Likewise, Rousseau loved solitude, but he included dialogues within his writing, and even wrote the bizarre book Rousseau Judge of Jean-Jacques (1776) in which he presented two versions of himself debating with each other.

Western philosophy has its origins in conversation, in face-to-face discussions about reality, our place in the cosmos, and how we should live. It began with a sense of mystery, wonder, and confusion, and the powerful desire to get beyond mere appearances to find truth or, if not that, at least some kind of wisdom or balance.

Socrates started the conversation about philosophical conversation. This shabby eccentric who wandered the marketplace in fifth-century Athens accosting passersby and cross-questioning them in his celebrated style set the pattern for philosophical discussion and teaching. His pupil Plato crafted eloquent Socratic dialogues that, we assume, capture something of what it was like to be harangued and goaded by his mentor, though perhaps they’re more of a ventriloquist act. Socrates himself, if we believe Plato’s dialogue Phaedrus, had no great respect for the written word. He argued that it was inferior to the spoken. A page of writing might seem intelligent, but whatever question you ask of it, it responds in precisely the same way each time you read it — as this sentence will, no matter how many times you return to it.

Besides, why would a thinker cast seeds on barren soil? Surely it is better to sow then where they’re likely to grow, to share your ideas in the way most suited to the audience, to adapt what you say to whoever is in front of you. Wittgenstein made a similar point in his notebooks when he wrote: ‘Telling someone something he will not understand is pointless, even if you add he will not understand it.’ The inflections of speech allowed Socrates to exercise his famous irony, to lay emphasis, to tease, cajole, and play, all of which is liable to be misunderstood on the page. A philosopher might jot down a few notes as a reminder of passing thoughts, Socrates suggested, but, for philosophical communication, conversation was king.

Plato’s use of dialogues reflected the centrality of discussion in philosophy. Sadly, with the exceptions of David Hume in his Dialogues Concerning Natural Religion (1779) and Søren Kierkegaard in Either/Or (1843), in which he uses personae presenting alternative viewpoints from within, few philosophers have handled multiple voices well. Many purport to play devil’s advocate against their own ideas but, as John Stuart Mill recognised, imagined critics can be much less forceful and use weaker arguments than the real thing.

Even now, philosophy is best taught using the Socratic method of question and answer. True, the demands of large lectures make interaction difficult but, as the Harvard professor Michael Sandel has shown with his Justice lectures and in his discussions about the public good, even here conversation and dialogue are possible. This is in many ways an improvement on Wittgenstein’s teaching style, which, according to contemporary accounts, involved students watching this tormented genius as he wrestled with his own developing ideas in front of them, occasionally pausing for minutes to stare at his upturned hand, at other times cursing his own stupidity: ‘What a damn fool I am!’ Arresting as that must have been, and superior in many ways to a rehearsed monologue that has been inflicted ad nauseam on undergraduates, it lacks the cut and thrust of Socratic questioning.

New technology is changing the landscape in which philosophical conversations — and arguably all conversations – take place. It has allowed contemporary philosophers to reach global audiences with their ideas, and to take philosophy beyond the lecture halls. But there is more to this ‘spoken philosophy’ than simply the words uttered, and the ideas discussed. Audible non-verbal aspects of the interaction, such as hearing the smile in someone’s voice, a moment of impatience, a pause (of doubt perhaps?), or insight — these factors humanise philosophy. They make it impossible to think of it as just a mechanical application of rigorous logic, and reveal something about the thinker as well as the position taken. Enthusiasm expressed through the voice can be contagious and inspirational.

Hobbes responded to Descartes’ Meditations in writing, but imagine how much more fascinating it would have been to hear and experience the two thinkers in a recorded public dialogue. Equally, if we could listen to a recording of Wittgenstein discussing his Tractatus with Frank Ramsey, one of his most perceptive early readers, it might well transform our views of both thinkers. The equivalent of these imagined conversations are being recorded now, both within and outside universities. They are freely available on the internet: on YouTube, iTunes and elsewhere, if you know where to look.

The point of philosophy is not to become a walking Wikipedia or ambulant data bank

Without conversation and challenge, philosophy very quickly lapses in to the dead dogma that Mill feared. But that does not mean that every viewpoint is equally valuable, or that we should accept that each person finds their own truth. Every great philosopher has been driven by an attempt to get beyond appearances and to say something important about how things really are. Philosophy is a subject that weighs positions, not just airs them. Conversation without critical judgment becomes mere chatter and airing of different opinions — as William Empson wrote in his poem ‘Let It Go’ (1949):

The contradictions cover such a range.

The talk would talk and go so far aslant.

You don’t want madhouse and the whole thing there.

However, it was John Stuart Mill who crystallised the importance of having your ideas challenged through engagement with others who disagree with you. In the second chapter of On Liberty (1859), he argued for the immense value of dissenting voices. It is the dissenters who force us to think, who challenge received opinion, who nudge us away from dead dogma to beliefs that have survived critical challenge, the best that we can hope for. Dissenters are of great value even when they are largely or even totally mistaken in their beliefs. As he put it: ‘Both teachers and learners go to sleep at their post, as soon as there is no enemy in the field.’

Whenever philosophical education lapses into learning facts about history and texts, regurgitating an instructor’s views, or learning from a textbook, it moves away from its Socratic roots in conversation. Then it becomes so much the worse for philosophy and for the students on the receiving end of what the radical educationalist Paolo Freire referred to pejoratively in Pedagogy of the Oppressed (1970) as the ‘banking’ of knowledge. The point of philosophy is not to have a range of facts at your disposal, though that might be useful, nor to become a walking Wikipedia or ambulant data bank: rather, it is to develop the skills and sensitivity to be able to argue about some of the most significant questions we can ask ourselves, questions about reality and appearance, life and death, god and society. As Plato’s Socrates tells us, ‘These are not trivial questions we are discussing here, we are discussing how to live.’