Pre-publication draft of an essay I wrote for IAI, forthcoming.
I guess most people reading this think the beliefs that the Moon Landings were faked, that fairies are real, and that their dead Auntie is in the room with them, are pretty obviously unreasonable. The beliefs that the universe is billions of years old, that Japan exists, and that bacteria cause infections are, on the other hand, considered eminently reasonable. Most of us think we are pretty good at recognizing reasonable and unreasonable beliefs when we come across them. However, we can begin to struggle when it comes to pinning down exactly what makes a belief reasonable or unreasonable.
I am going to outline one tell-tale sign that, while you might think your beliefs are reasonable, they’re not. I call it ‘But it fits!’
Our beliefs are often challenged. I might believe that the Matterhorn is near Chamonix. Someone points out, using a map, that I am mistaken: the Matterhorn is near Zermatt. I must have been thinking of Mont Blanc. I want to believe what’s true, so, having been given good reason to think I was wrong, I’ll no doubt change my belief.
However, it can be much more difficult to change our beliefs when we have a great deal invested in those beliefs. Someone who holds religious beliefs may have invested a great deal in those beliefs. They may have donated a large amount of time and money to their church. Losing their religious belief may result in the loss of things that really matter to them - perhaps their sense of who they are, of what’s right and wrong. Loss of religious belief can even result in loss of friends and family, and even career. Someone that has spent their entire professional career advertising cigarettes, believing that cigarettes are fairly safe, has similarly invested a great deal in that belief. The same is true of someone with strong political beliefs, who has spent many years donating to and campaigned for a political movement and whose friends and colleagues all share that same political affiliation. In each, abandoning belief can be very painful, socially, financially, in terms of their sense of identity and purpose. If compelling evidence is presented against such beliefs, it’s unlikely the person will just change their mind. What’s far more likely is that they will instead adopt the strategy of ‘But it fits!’ in an attempt to ensure that no evidence can count decisively against their belief.
Tom believes that cats are hyper-intelligent alien spies from Mars planning an imminent Martian invasion. Tom’s friend Alice tries to convince him he’s being highly unreasonable, and she challenge him with all sorts of evidence:
Alice: ‘But Tom, cats clearly aren’t hyper-intelligent Martians - they can’t even speak.’
Tom: ‘They can speak, but of course being hyper-intelligent they ingeniously hide their intelligence and speech from us.’
Alice: ‘But how do they communicate with Mars? I have looked in the cat’s bed and there’s no transmitter.’
Tom: ‘The transmitters are hidden in their heads - that’s why we don’t find them.’
Alice: ‘But I am a vet and have x-rayed many a cat’s head. There are no transmitters in there.’
Tom: ‘Being hyper-intelligent, the cats have developed technology that appears to be organic brain matter - even in an x-ray’
Alice: ‘But there are no radio signals coming out of the cats’ heads.’
Tom: ‘Of course not, these are hyper-intelligent beings that have developed methods of communication far beyond our ability to detect them,’
Alice: ‘But cats can’t live on Mars. They couldn’t breathe, plus the surface of Mars shows no signs of feline Martian civilization.’
Tom: ‘Of course not: the cats live in deep underground bunkers where they have developed an artificial atmosphere. But the Earth now has a far better environment for cats - which is why they’re going to invade.’
You can see how this conversation might keep going forever. Alice can provide what would ordinarily be considered compelling evidence that cats aren’t Martian spies, but, with sufficient ingenuity, there’s always a way of showing that Alice’s evidence is, after all, consistent with Tom theory, so that Tom can, without logical contradiction, both accept the evidence and maintain his belief. I call this strategy of explaining away the evidence ‘But it fits!’: no matter how much the evidence might pile up against a belief, there’s always a way of making the evidence and the theory fit together.
Explaining away the evidence isn’t always irrational. There’s overwhelming evidence that water boils at 100 degrees centigrade at one atmosphere. But suppose an experiment is done in which water appears not to boil at that temperature. Ought I now to abandon my belief about the boiling point of water? Of course not. It’s reasonable for me to assume that something went wrong with the experiment. I can quite justifiably explain away this bit of evidence against what I believe by suggesting that perhaps the thermometer was faulty, for example.
However, if we start habitually explaining away the evidence against what we believe – so that we won’t let anything ever count decisively against it - that’s a warning sign that we’re sliding into irrationality. And of course, that’s exactly what Tom does. The evidence against what he believes mounts up and up, but he just keeps on explaining that evidence away. It is likely Tom will keep doing this ad nauseum - he won’t ever allow his belief that cats are Martian spies to be falsified. A belief defended in this way floats entirely free from reality. What’s believed is believed come what may, irrespective of any and all evidence against it. That’s irrational.
Like most people, I am prone to sliding into adopting this strategy when my beliefs are challenged and I have a lot invested in those beliefs. I have caught myself doing it. It’s something we really need to be on-guard against.
A dramatic illustration of ‘But it fits!’ is its use to defend Young Earth Creationism. Young Earth Creationists believe in the literal truth of Genesis, and so believe that the entire universe is less than ten thousand years old and that all ‘kinds’ were created just as described in Genesis. They entirely reject both the theory of evolution and the view that the universe is billions of years old.
On the face of it, Young Earth Creationism is clearly absurd. Surely there’s a mountain of evidence against it, from light from distant galaxies (which would take millions of years to get here), to the fossil record. How on Earth do Young Earth Creationists deal with this evidence?
They employ the strategy of explaining away. Many Creationists explain the fossil record using the Biblical Flood, on which Noah floated his ark. That flood produced huge mud deposits which set into the sedimentary layers we find beneath our feet. As creatures drowned or were buried and different ecological zones submerged by the Flood, they were buried in a particular order. This explains the fossil record. At the bottom we find the creatures covered first - simple marine life. Then as we move up through the layers we find other creatures, including, eventually, land dwelling creatures and mammals. Humans used their intelligence to avoid being buried until very late on, which is why we find humans remains only in the very topmost layers. But then, says our Creationist, the fossil record is not evidence against Young Earth Creationism. The evidence ‘fits’ the fossil record just as well as it does the orthodox scientific theory that the Earth is ancient and creatures evolved over millions of years.
Similar strategies are used to explain away all the other evidence that might seem, on the face of it, to conclusively refute Young Earth Creationism. The Creationist Ken Ham has a website called Answers in Genesis that develops Creationism-friendly explanations for much of the evidence that scientists think undermines Creationism.
Ham believes that, by explaining the fossil record and other supposed evidence against his theory, he can show that it ‘fits’ - and is therefore scientifically confirmed - by that evidence:
Increasing numbers of scientists are realising that when you take the Bible as your basis and build your models of science and history upon it, all the evidence from the living animals and plants, the fossils, and the cultures, fits. This confirms that The Bible really is the word of God and can be trusted totally.
According to Ham, orthodox scientists do the same thing - they too look for ways to make the theory to which they have already committed themselves fit - be consistent with - the observed evidence:
Evolutionists have their own theory into which they try to fit the data.
(my underlines)
Ham understands science to be a matter of making your preferred theories fit the observed evidence. To the extent that the fit can be achieved, the theory is confirmed by that evidence. So, according to Ham, Young Earth Creationism is as well-confirmed a scientific theory as are the theories that the Earth is billions of years old and species have evolved over millions of years. Ham’s Answers in Genesis website provides very many examples of how the evidence against Young Earth Creationism can be explained away.
Ham has entirely misunderstood what confirmation is - whatever it is, it isn’t a matter of achieving ‘fit’ or consistency with the data. If it was, then Tom’s theory that cats are really Martian spies would be as reasonable and well-confirmed as the view that they’re benign creatures of Earthly origin. (So what is confirmation? In a nutshell – for an observation of x to confirm y, we need to look at the probability of observing x if y is true, versus the probability of observing x if y is false. So, for example, Mary’s wet coat and umbrella are evidence it is raining because we are rather more likely to observe her wet shoes and umbrella if it is raining than if it is not)
The moral is: Beware ‘But it fits!” a strategy that can be used to make even absurd beliefs seem quite reasonable, and, in the case of Young Earth Creationism, even appear ‘scientific’. It is one of many of such strategies - for more examples, see my book: Believing Bullshit (Prometheus).
You may wonder why all this matters? Well, it may not matter if we don’t much care about whether our beliefs are true. But if we do want our beliefs to to be true, then it’s essential that they are sensitive to how things are. The ‘But it fits!’ strategy guarantees they won’t be.
Ham has entirely misunderstood what confirmation is - whatever it is, it isn’t a matter of achieving ‘fit’ or consistency with the data. If it was, then Tom’s theory that cats are really Martian spies would be as reasonable and well-confirmed as the view that they’re benign creatures of Earthly origin. (So what is confirmation? In a nutshell – for an observation of x to confirm y, we need to look at the probability of observing x if y is true, versus the probability of observing x if y is false. So, for example, Mary’s wet coat and umbrella are evidence it is raining because we are rather more likely to observe her wet shoes and umbrella if it is raining than if it is not)
The moral is: Beware ‘But it fits!” a strategy that can be used to make even absurd beliefs seem quite reasonable, and, in the case of Young Earth Creationism, even appear ‘scientific’. It is one of many of such strategies - for more examples, see my book: Believing Bullshit (Prometheus).
You may wonder why all this matters? Well, it may not matter if we don’t much care about whether our beliefs are true. But if we do want our beliefs to to be true, then it’s essential that they are sensitive to how things are. The ‘But it fits!’ strategy guarantees they won’t be.
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