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Belief in human rationality requires a greater leap of faith than any religion, argues John Gray.

I don't know how many times I've heard religion being described as childish. It's one of those uncritically accepted ideas - perhaps I should say memes - that have been floating around for generations. Even many religious people seem to accept that there's something at least child-like about their faith. Believing in God, they sometimes say, is a bond between human beings and an infinitely wiser power - we should trust in God just as we would a loving parent. When they hear this, our evangelical atheists feel vindicated in their crusade. In their view, nothing could be more childish than a relationship in which human beings are utterly dependent on a supernatural power. For these atheists, putting your trust in such an imaginary being is the essence of childishness.

Speaking as an atheist myself, I can't help smiling when I hear religion being mocked in this way. Looking at the world as it has been and continues to be at the present time, it's belief in human reason that's childish. Religious faith is based on accepting that we know very little of God. But we know a great deal about human beings, and one of the things we know for sure is that we're not rational animals. Believing in the power of human reason requires a greater leap of faith than believing in God.

Find out more A Point of View is usually broadcast on Fridays on Radio 4 at 20:50 GMT and repeated Sundays 08:50 GMT

John Gray is a political philosopher and author of False Dawn: The Delusions of Global Capitalism Listen to A Point of View on the iPlayer BBC Podcasts - A Point of View

If human beings were potentially capable of applying reason in their lives they would show some sign of learning from what they had done wrong in the past, but history and everyday practice show them committing the same follies over and over again. They would alter their beliefs in accordance with facts, but clinging to beliefs in the face of contrary evidence is one of the most powerful and enduring human traits.

Outside of some areas of science, human beings rarely give up their convictions just because they can be shown to be false. No doubt we can become a little more reasonable, at least for a time, in some parts of our lives, but being reasonable means accepting that many human problems aren't actually soluble, and our persistent irrationality is one of these problems. At its best, religion is an antidote against the prevailing type of credulity - in our day, a naive faith in the boundless capacities of the human mind.

The belief in reason that is being promoted today rests on a number of childishly simple ideas. One of the commonest is that history's crimes are mistakes that can be avoided in future as we acquire greater knowledge. But human evil isn't a type of error that can be discarded like an obsolete scientific theory. If history teaches us anything it's that hatred and cruelty are permanent human flaws, which find expression whatever beliefs people may profess.

In Europe before and during World War Two, persecution and genocide were supported by racial and eugenic theories, which allowed some groups to be demonised. These theories were pseudo-science of the worst kind, but it wasn't this that discredited them. They were exposed for what they were by the defeat of Nazism, which revealed the horrors to which they had led. Subsequent investigation has since demonstrated that such theories are scientifically worthless. But the habit of demonising other human beings hasn't gone away. The same minorities that were targeted in the past - Jews, Roma, immigrants and gay people, for example - are being targeted in many countries today.

Persecution under the Nazis

Image copyright Getty Images Image caption A woman hides her face as she sits at a bench marked "for Jews only", 1938

Between 1933 and 1945, Nazi Germany persecuted and killed people who did not conform to its ideas of racial and biological "purity"

Systematic murder of six million Jews is known as the Holocaust

Nazis also targeted and killed millions of Slavs and "asiatics", 200,000 Gypsies and members of various other groups

Thousands of people, including Germans of African descent, were forcibly sterilised

BBC History: Nazi genocide timeline

Across much of Europe, the politics of hate has returned with the rise of the far right. From one point of view, this isn't surprising. The lesson of history is that in conditions such as those that exist in some parts of Europe, old bigotries and prejudices become more virulent and more dangerous. When incomes fall, jobs are scarce and there's no prospect of improvement, those who appear different tend to be scapegoated and blamed for society's ills. What may seem more surprising is that Europe's elites are so complacent. Dark forces are on the move again, and yet as far as those who govern the continent are concerned, business goes on much as usual.

This complacency testifies to another enduring human flaw - sticking to a project when it has become self-defeating in its effects. Pushing ahead with ever greater union when large parts of the continent are suffering massive social dislocation fuels the very divisions the European Union was supposed to overcome. If Europe's elites were even half-way reasonable, they would put their grand project on one side and focus on dealing with this danger. But like true believers everywhere, they're convinced the only thing wrong with their dream is that it hasn't yet been fully realised. Everything suggests they'll push on until the entire edifice they've constructed cracks under the strain.

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Science may yet confirm what history so strongly suggests - irrationality is hard-wired in the human animal

The refusal to see clear and present danger shows that the idea that human beings base their beliefs on their experience is just a fairy-tale. The opposite is closer to the truth - shaping their perceptions according to what they already believe, human beings block out from their minds anything that disturbs their view of the world. Psychologists who examine this tendency - sometimes called cognitive dissonance - have speculated that refusing to face the truth may confer an evolutionary advantage. Screening out unpleasant or disturbing facts may, in some circumstances, give some people a better chance of survival. But at the same time this tendency leads us all into one folly after another. Many regard science as the supreme embodiment of human reason, but science may yet confirm what history so strongly suggests - irrationality is hard-wired in the human animal.

Certainly unreason can be tempered by the hard-won practices of civilisation, but civilisation will always be a precarious achievement. To believe that human beings can be much improved by rational argument is to assume that they are already reasonable, which is obviously false. The old doctrine of original sin contained a vital truth - there are impulses of irrational destructiveness in every one of us.

Image copyright Getty Images Image caption Bertrand Russell (1872-1970) was a philosopher, logician, and social reformer

This was the conclusion of the economist Maynard Keynes - by any standards one of the most brilliant minds of the last century. In his memoir My Early Beliefs, Keynes described how he renounced the faith in reason he'd had as a young man in Cambridge. Commenting on his friend the logician and social reformer Bertrand Russell, Keynes observed: "Bertie sustained simultaneously a pair of opinions ludicrously incompatible. He held that human affairs are carried on in a most irrational fashion, but that the remedy was quite simple and easy, since all we had to do was carry them on rationally."

More from the Magazine Image copyright Getty Images The influential Cambridge economist John Maynard Keynes figured prominently in the anxious debates that have gone on since the crash of 2007-2008 - so what would he have made of the current economic situation? A Point of View: What would Keynes do?

Today's believers in reason are caught in the same contradiction. To imagine that we can become much more rational than we have ever been, if only we want to be and try hard enough, is itself thoroughly irrational. It's an example of magical thinking, an expression of the belief in the omnipotence of human will that psychoanalysts identify as the fundamental infantile fantasy.

There's something deliciously comic in the spectacle of people railing against unreason being themselves so obviously in the grip of a childish delusion. But we shouldn't be too hard on our anti-religious evangelists. Evidently they need their simple faith in reason - it seems to be the only thing that keeps them going. That doesn't mean we have to take them seriously. The notion that human life could ever be ruled by reason is an exercise in make-believe more far-fetched than any of the stories we were told as children. We'd all be better off if we saw ourselves as we are - intermittently and only ever partly-rational creatures, who never really grow up.

A Point of View is broadcast on Fridays on Radio 4 at 20:50 BST and repeated Sundays 08:50 BST or listen on BBC iPlayer

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