The Science of Discworld IV

better to serve their practitioners. Those that didn’t do so well have been lost to history. Few people now believe in Odin or Osiris.
    Modern religions, with their beliefs in gods or at least in the supernatural, have all achieved congregations that seem happy with the hierarchy of senior people who determine the letters of the faith. This complicity between congregants and the hierarchy makes the belief system almost irrelevant, even though it seems to the congregantsto be central. The joint activities, the singing and the praying, the individual commitments in common, give the congregants a warm feeling of belonging. From outside, each of these faiths seems a beautiful harmony, the odd spat over homosexuals or female bishops aside. It’s not surprising that rationality can’t edge its way in.
    For decades, psychologists have been making scientific studies of religious belief; not with a view to proving or disproving the existence of any particular flavour of deity, but trying to find out what goes on inside the minds of believers. Some have concluded that belief in the supernatural is a more or less inevitable consequence of evolutionary survival value (an ironic finding, if true), because it knits human cultures together. Only recently has it occurred to a few psychologists that perhaps the thought processes of atheists also need to be investigated, since such people form a fairly large group that seems to be immune to these supposed evolutionary pressures. Comparing believers with non-believers is likely to shed more light on both.
    Even if religion and other kinds of belief in the supernatural really are natural consequences of humanity’s past history, built into our thought processes by evolution, there is no compulsion to continue to think that way. Our sporadic tendency towards violence, especially against each other, can also be explained in similar terms, but there seems to be a widespread (and sensible) view that this does not excuse violent behaviour. A true human being should be able to override such innate urges by an act of will. The same can be said of belief in the supernatural: by exercising our intelligence we can train ourselves to disbelieve claims for which there is no clear evidence. Of course, believers think that there
is
evidence – certainly enough to convince them – but it tends to be obscure and heavily dependent on interpretation.
    An instructive example of the influence of religious belief on rational judgement occurred in 2012 when Sanal Edamaruku,founder of Rationalist International and President of the Indian Rationalist Association, was invited to examine a miracle. What follows is based on an interview with Edamaruku published in
New Scientist
, and we report what was alleged there. fn1
    The miracle occurred at a Catholic church in Mumbai, where water was dripping spontaneously from the feet of a statue of Christ on the cross. This event was interpreted as a sign from God – a holy miracle – and flocks of believers collected and drank the water, apparently thinking that it was holy water that would cure all manner of illnesses. A television station asked Edamaruku to comment, and consonant with his position, he rejected the claim of a miracle. Since his view was at that moment purely a matter of opinion, the TV company challenged him to provide scientific proof, which of course required visiting the church and taking a look.
    The church authorities gave their approval. It didn’t take long to find the cause of the ‘miracle’. A drainage channel from a washroom passed beneath the cross’s concrete plinth. A quick look at the drain revealed that it was blocked. The walls behind the cross, and the wooden cross itself, were soaking up drainage water through capillary action. Some of the water was emerging through a nail hole and running down over the statue’s feet. Edamaruku took photographs to document the cause.
    Point made, you will imagine. Well, yes – but. Edamaruku had long been a thorn in the side of religious groups, and his finding caused them some embarrassment. They could have used System 2 thinking to investigate the likely causes of dripping water, or just called a plumber like most sensible people would have done when they found water dripping from places where water ought not to be. Instead, they made a System 1 judgement and plumped for a supernatural explanation. But it’s not a great idea to have people drinkingdilute sewage, even if they do