When I was a child I encountered many superstitious beliefs:
“If you break a mirror you will get seven years’ bad luck.”
“If you make someone a present of a knife or scissors, the person must pay you something to avoid cutting the friendship.”
“If it rains on St Swithin’s Day (15th July), it will rain for the next 40 days.”

I suspect that most readers did so too. The actual beliefs depend on the culture, but all cultures have them.

We like to think of ourselves as rational beings – we have even named our species Homo Sapiens. Perhaps Homo Credulus would be better. We overrate our powers of discernment and are all too ready to be fooled by conjurers and confidence tricksters. Science, which really does help us to think more rationally, is a latecomer in the story of human evolution. Tens of thousands of years ago, our ancestors had no such help. They had to do their best to make sense of a puzzling and dangerous world, using what simple tools and limited knowledge they had.

They survived by looking for patterns. We still do. If A is followed by B, then perhaps A causes B. If something good happens when you are wearing a particular shirt, you might think that the shirt contributed significantly to the outcome. It then becomes your “lucky shirt”. But the mere sequence of events proves nothing on its own.

The whole idea of good and bad luck is part of magical thinking: the idea that events can be influenced by invisible powers which we in turn can influence through incantations or rituals. Despite plenty of evidence to the contrary, we think that the world ought to be fair, rewarding the good and punishing the bad. At the same time, we may believe that some people can tilt the scales through their special powers. Such people can be revered as shamans or priests – or reviled as witches.

Belief in magic and sorcery has been found in all cultures. It is far more common than a high degree of rationality. If misfortune can be attributed to sorcery, it makes good sense to act against the sorcerers. In the West, belief in witchcraft has died down, but our record just a few centuries ago was very unpleasant. Under the influence of the churches, supposed witches were tortured and killed. The Bible proclaimed, “thou shalt not suffer a witch to live”. Learned theologians recommended methods of dealing with witches. The most notorious of such works was the Malleus Maleficarum, or Hammer of Witches, produced in 1486.

The persecution of witches continued over several centuries. Initiated in the Middle Ages by the Catholic Church, it was continued by Protestants. One insidious aspect was the probable fate of those who expressed scepticism about the existence of witchcraft. As a denial of holy scripture, it constituted heresy or blasphemy, and was liable to severe, even capital, punishment. Only the rise of modern science led to a change in attitudes. Unfortunately, belief in witchcraft still persists in many parts of the world. Even in the West, some churches still apparently hold that people can be “possessed” by evil spirits, which can be defeated by exorcism.

Even without believing in sorcery, many of us willingly embrace shaky beliefs on almost no evidence. In the West, millions of people read the daily newspaper horoscopes, as though it made any sense to suppose that a single paragraph could predict the fate of one-twelfth of humanity. In the East, many people take the advice of astrologers on such crucial life events as choosing a marital partner or fixing the date of marriage. There are even university courses in astrology and feng shui. Many people also accept dubious “healing” methods, such as homeopathy, that are without scientific basis.

Another manifestation of superstitious thinking is the readiness of large numbers of people to believe conspiracy theories. Of course, conspiracies do exist, but there is very little evidence for most conspiracy theories, based purely on conjecture. Millions of Muslims (and quite a few Americans) refuse to believe that the New York World Trade Centre was destroyed by Muslims, even though Osama bin Laden was happy to claim responsibility. No, it must have been done by the American or Israeli secret services. And millions of Americans believe that contact was made with extra-terrestrials at Roswell in 1947, an event hushed up by Government ever since.

Some of the most lethal conspiracy theories have been perpetrated by religious leaders. Muslim clerics in Nigeria spread the idea that vaccination against polio was a Western conspiracy against the people. As a result, many children went unvaccinated and polio infection rates rose. The fear spread from Nigeria to other Muslim populations, resulting in deaths or paralysis from polio of children across the world.

Some Catholic Church leaders have propagated false information about the use of condoms as a protection against HIV. One story was that the condoms had small holes which transmitted the virus. A more recent one was that condoms were deliberately infected with HIV. The result has been a setback in anti-HIV campaigns, resulting in many avoidable infections and deaths.

Wherever we look, we can see examples of irrational, superstitious or magical thinking. If we examine ourselves carefully, we will probably find that we ourselves are not immune. We have to try to think critically and sceptically. That does not mean disbelieving everything on principle, but trying to assess the evidence and being ready to suspend judgement if necessary. Let us salute those who are working hard to bring education and rationality to the uneducated and disadvantaged. You will see some heart-warming examples in the pages that follow.

Diana Brown is the current editor of International Humanist News