Who were the Sceptics? 

The Sceptics were a philosophical school that arose around the same time as the Stoics and the Epicureans, in the third century BC. They opposed these rival schools, insisting that they dogmatically claimed to ‘know’ the nature of reality and the existence or non-existence of God. The Sceptics argued that Socrates had revealed to us how little we really know about truth or God. Instead of clinging rigidly to our dogmatic beliefs, we should admit the limits of our knowledge, and suspend belief.

The founder of Scepticism, Pyrrho of Elis (a scultpure of whom is shown on the right), went so far as to claim we should not hold any beliefs, but should embrace the ‘doctrine of incomprehensibility’, emptying our minds of all dogmatism and certainty. He is said to have discovered this doctrine when he travelled to India with the army of Alexander the Great, and there observed the sadhus and fakirs emptying their minds of all thoughts while in meditation.

Presumably, sadhus are emptying their minds of thoughts in order to come closer to God or to truth. Why would Sceptics suspend belief? 

One of Pyrrho’s later disciples, a doctor called Sextus Empiricus, suggested that Scepticism, like Stoicism and Epicureanism, offered its followers a therapy for the soul. What causes emotional disturbances is our over-dogmatic beliefs. By freeing ourselves from dogmatic opinions, we achieve a calm and untroubled disposition. So the goal of the Sceptic way of life is a mind free from emotional agitation.

Ah, but if we’re practicing Scepticism for the ‘goal’ of an untroubled mind, then isn’t that based on the belief that an untroubled mind is a ‘good’? 

Yes, there is a paradox there. Critics of Scepticism argued that all action is based on the belief ‘this action is worth doing’. If we suspended all beliefs, we would be paralysed. We’d be lucky to make it through the week: if we were crossing the road and a car came towards us, why would we step out of the way? That would be an acceptance of the belief ‘it is good to live’. In fact, we read that Pyrrho had to be continually pulled out of the way of traffic by his disciples!

So how did the Sceptics deal with this criticism? 

There was a particular school of Sceptics know as the Academic Sceptics, so-called because for a while they were in charge of Plato’s Academy in Athens. Academic Sceptics accepted Pyrrho’s insistence that we can never be sure what is true or not. But they argued we could lead our lives based on what we thought was probable.

This form of Scepticism became very influential in modern philosophy, particularly from the 17th century on, when it merged with empiricism in the philosophies of John Locke, David Hume and others. It was especially useful as a philosophical critique against Christianity. David Hume (pictured on the right) argued that all our knowledge is based on hypotheses, any of which could turn out to be wrong at any moment. Just because the sun has risen every day of our lives, that doesn’t mean it will definitely rise tomorrow. Like the ancient Sceptics, Hume suggests we should be wary of over-certainty, dogma and fanaticism, which harms both ourselves and our societies.

Can Scepticism be a form of therapy today? 

Yes, I think it can. Scepticism, like the other philosophies of the Socratic tradition, is based on the cognitive theory of the emotions. It’s based on the idea that what causes us suffering are our false beliefs and opinions, therefore, to free ourselves from suffering, we should learn to take a sceptical attitude to our beliefs. When we feel a powerful and destructive emotion, we should look for the belief or interpretation that gave rise to it, and then ask ourselves: ‘Is this interpretation definitely true? Where’s the evidence for it? Could I choose to see this situation differently?’

According to Cognitive Behavioural Therapy, many emotional disorders are caused by over-certainty and excessive dogmatism in our beliefs. A depressed person is sure the universe is against them and nothing they do will ever work out. A socially anxious person is sure that other people don’t like him or her. The same is true even of people with psychosis: a schizophrenic is sure that the voices they hear are really angels or demons who wield an absolute power over them.

We can learn to be more Sceptical to our thoughts and beliefs, not treating them as absolute deities, but rather as things that come and go, which we can choose to accept or choose to reject.

You talk in the chapter about the Landmark Forum, a self-help school which you suggest teaches a form of radical Socratic Scepticism. Tell us a bit about that. 

In the chapter, I visit one of the Landmark Forum’s weekend seminars, and watch how Landmark tries to free people from their hang-ups by getting them to see the emptiness of the narrative through which they view the world. It’s a weird weekend – you’re in a hall with 200 people, all primed and ready to achieve a ‘breakthrough’, and they stand up one-by-one and share stories of their secrets, their hidden traumas, and then their stories are quite aggressively deconstructed by the group ‘Leader’. The idea is you carry around a story about reality which you are sure is true, but it may just be a ‘racket’ – a self-serving fiction. Landmark tries to free people from their fictions, show them the emptiness of it, in order to usher them into a ‘new realm of possibility’. Many people find Landmark a powerful, even life-changing experience. But, as I explore in the book, there are also risks. Having your ego-narrative publicly deconstructed can be quite a full-on experience!

Do you think Scepticism be a way of life today, or the foundation for a community? 

Many people are trying to answer this question today. People are trying to create a sort of religion of Scepticism: think of AC Grayling’s Humanist Bible, or Richard Dawkins’ atheist children’s books, or Alain de Botton’s Religion for Atheists.

James 'The Amazing' Randi on a poster for a TAM gathering of Skeptics

In fact, Scepticism today is already a flourishing movement, with millions of members all over the world, who meet up at organisations like Skeptics In the Pub, and at conferences like The Amazing Meeting (TAM), an annual gathering of hundreds of Sceptics which takes place in Las Vegas each year. In the book, I go to to TAM and talk to Sceptics like James ‘The Amazing’ Randi and Michael Shermer – you can watch a video I made of my time among the Skeptics here.  The Sceptic movement has been greatly helped by the internet: before the internet, there might be one lonely atheist living in the American Bible Belt. The internet has connected such people, and given them access to Skeptic chatrooms, forums, and podcasts like The Skeptic’s Guide to the Universe. Modern Scepticism has even become a political ideology, with its own Washington lobby group. But turning Scepticism into a movement or ideology has its risks.


A political mass movement needs dogma to give itself coherence, like a marching band keeping soldiers in steps. It also needs clearly defined heroes and villains. Modern Scepticism now has its dogma or creed: it embraces a biochemical view of mental illness, for example. It embraces the view that consciousness can be reduced to its neural correlates, and that it is confined to the individual brain. It embraces the view there is definitely no God, and nothing of our psyche survives after death. And, above all, it embraces the view that religions are completely harmful and toxic, and they should be attacked and abolished. Science and religion are engaged in a zero sum game for influence, and truth and justice is entirely on the side of science, and against religion. God forbid anyone walks out of line and challenges this dogma – they will feel the fury of the online Sceptic army. But this Sceptic ideology can degenerate into mindless obedience to dogma, and to uncritical statements like ‘science is good’ or ‘I believe in science’, both of which I heard at The Amazing Meeting. It can also degenerate into a mindless reverence for the movement’s leaders, and the sort of vicious attacking of anyone who disagrees that one usually associates with fundamentalist religion.

How could the Sceptic movement avoid this? 

A more intelligent Scepticism, I suggest, would recognise that knowledge has always progressed through the mavericks, through those who refuse to accept the dogma and consensus of their time, and who are prepared to be laughed at or attacked for their independent thinking. A more intelligent Scepticism recognises that human irrationality is not confined to religious traditions, and that we can also have irrational faith in scientific theories. The Credit Crunch, for example, was partly caused by our culture’s almost religious faith in the free market, and in the power of economists to predict the future. There are many examples of modern Sceptics who express a healthy Scepticism towards the social sciences, such as Nassim Nicholas Taleb or Jon Ronson.