Knowing things that just ain't so

Everybody "knows" things that are not true. It is the nature of humanity that nobody can know everything and all of us have misconceptions and gaps in our knowledge. Most of us recognise this and seek out people with appropriate expertise when we come across something that we don't know and accept revision to our internal knowledge base when we get evidence that contradicts what we believe to be true. There is, however, a very large number of people who seem content to be wrong and who cannot be convinced to change their minds when presented with evidence

Human existence (and much of the life of non-human animals) is a continual process of extracting meaning from patterns. The existence of optical illusions is evidence that we can get this wrong, but there are good evolutionary reasons for why we have a propensity for being wrong.

When our ancestors were walking in the long grass in Africa they could have two possible reactions to a rustle in the hedgerow. They could assume it was something dangerous and take evasive action or they could assume it was the wind and wait for further evidence. If they ran away and it really was the wind they had made what is called a Type 1 error – a false positive. They might be tired and embarrassed but they were still alive. If they waited for more information and it really was a lion looking for lunch they had made a Type 2 error – a false negative. Over evolutionary time it became productive to tend towards Type 1 errors, because the Type 2s sometimes didn't survive to breed. We can still see this today in non-human animals where the default behaviour to an unexpected or unidentified stimulus is to flee. The tamest or most aggressive seagull will fly away if you run at it, even if you are carrying a bag of chips.

The difference between humans and non-humans, however, is that we are supposed to have reasoning power which we can apply to different situations to interpret what is going on. This is why we recognise optical illusions as illusions – we know we can't really be seeing what we think we are seeing. But what if we couldn't tell that we were wrong? Or worse still, wouldn't be interested in telling?

The major delusion afflicting mankind is religion, but I'm not going to spend too much time on that here. By definition religion relies on faith, and faith is belief without evidence. Some theologians say that looking for evidence to support faith is a sort of blasphemy as it indicates that faith is not strong enough. It is this reliance on faith that separates religion from science, and I am firmly in the camp that says that science has no business interacting with religion except where religion makes testable claims (like the age of the Earth) or where it can do harm. One aspect of religion that is of interest to science is the evolutionary basis for the presence of religion in almost all societies, but this is a matter for another day.

Resistance to evidence reaches its peak in conspiracy theories. Not only are all good conspiracies based on Type 1 errors, but a good conspiracist makes sure that those errors are never corrected. It is a common tactic of conspiracy believers to find some piece of apparently confirming evidence (or disconfirming evidence subsequently shown to be wrong) and use this to prove that all disconfirming evidence is wrong. Creationists use apparently anomalous radioactive dating of mud flows around Mount St Helens to show that radioactive dating is totally untrustworthy in all circumstances. Climate change deniers use two out of 11,000 emails to show that all climate scientists lie. Anti-vaccine campaigners point to vaccinated children who still become infected. Holocaust deniers demand to see documents where Hitler said "Kill the Jews".

What is common to all of these is a demand for certainty, and it illustrates the difference between confidence and faith. Faith implies certainty, so any true believer in a conspiracy (or any other mad idea, such as the existence of a mathematical method of trisecting an angle or the alien origin of crop circles) will resist any challenge because it removes certainty. Confidence, however, is what science is about – being right with the possibility of being wrong.

On the day that I am writing this CERN has announced that neutrinos travelling at greater than light speed might have been detected. The media is screaming "Einstein was wrong", but the scientists involved are wondering if they have made a mistake. Einstein didn't disprove Newton, just took knowledge in a different direction. If the CERN results are correct then we will know more than Einstein did in 1905. So what? It's finding out where we are wrong that makes science so exciting.

This article was published as the Naked Skeptic column in the November 2011 edition of Australasian Science