Think it through
1. Expect unexplained false sightings and huge coincidences
Our UFO story isn’t over yet. When the Star’s two-man investigative team couldn’t get any closer to the mysterious object, they eventually pulled over. The photographer took out his long lens to take a look: ‘Yep … that’s the planet Venus all right.’ It was later confirmed beyond any reasonable doubt that what all the witnesses had seen was just a planet. But what about that radar blip? It was a coincidence, perhaps caused by a flock of birds or unusual weather.
What moral should we draw from this case? Not, of course, that because this UFO report turned out to have a mundane explanation, all such reports can be similarly dismissed. But notice that, had the reporters not discovered the truth, this story would likely have gone down in the annals of ufology as one of the great unexplained cases. The moral I draw is that UFO cases that have multiple eyewitnesses and even independent hard evidence (the radar blip) may well crop up occasionally anyway, even if there are no alien craft in our skies.
We tend significantly to underestimate how prone to illusion and deception we are when it comes to the wacky and weird. In particular, we have a strong tendency to overdetect agency – to think we are witnessing a person, an alien or some other sort of creature or being – where in truth there’s none.
Psychologists have developed theories to account for this tendency to overdetect agency, including that we have evolved what’s called a hyperactive agency detecting device. Had our ancestors missed an agent – a sabre-toothed tiger or a rival, say – that might well have reduced their chances of surviving and reproducing. Believing an agent is present when it’s not, on the other hand, is likely to be far less costly. Consequently, we’ve evolved to err on the side of overdetection – often seeing agency where there is none. For example, when we observe a movement or pattern we can’t understand, such as the retrograde motion of a planet in the night sky, we’re likely to think the movement is explained by some hidden agent working behind the scenes (that Mars is actually a god, say).
One example of our tendency to overdetect agency is pareidolia: our tendency to find patterns – and, in particular, faces – in random noise. Stare at passing clouds or into the embers of a fire, and it’s easy to interpret the randomly generated shapes we see as faces, often spooky ones, staring back.
And, of course, nature is occasionally going to throw up the face-like patterns just by chance. One famous illustration was produced in 1976 by the Mars probe Viking Orbiter 1. As the probe passed over the Cydonia region, it photographed what appeared to be an enormous, reptilian-looking face 800 feet high and nearly 2 miles long. Some believe this ‘face on Mars’ was a relic of an ancient Martian civilisation, a bit like the Great Sphinx of Giza in Egypt. A book called The Monuments of Mars: A City on the Edge of Forever (1987) even speculated about this lost civilisation. However, later photos revealed the ‘face’ to be just a hill that looks face-like when lit a certain way. Take enough photos of Mars, and some will reveal face-like features just by chance.
The fact is, we should expect huge coincidences. Millions of pieces of bread are toasted each morning. One or two will exhibit face-like patterns just by chance, even without divine intervention. One such piece of toast that was said to show the face of the Virgin Mary (how do we know what she looked like?) was sold for $28,000. We think about so many people each day that eventually we’ll think about someone, the phone will ring, and it will be them. That’s to be expected, even if we’re not psychic. Yet many put down such coincidences to supernatural powers.
2. Understand what strong evidence actually is
When is a claim strongly confirmed by a piece of evidence? The following principle appears correct (it captures part of what confirmation theorists call the Bayes factor; for more on Bayesian approaches to assessing evidence, see the link at the end):
Evidence confirms a claim to the extent that the evidence is more likely if the claim is true than if it’s false.
Here’s a simple illustration. Suppose I’m in the basement and can’t see outside. Jane walks in with a wet coat and umbrella and tells me it’s raining. That’s pretty strong evidence it’s raining. Why? Well, it is of course possible that Jane is playing a prank on me with her wet coat and brolly. But it’s far more likely she would appear with a wet coat and umbrella and tell me it’s raining if that’s true than if it’s false. In fact, given just this new evidence, it may well be reasonable for me to believe it’s raining.
Here’s another example. Sometimes whales and dolphins are found with atavistic limbs – leg-like structures – where legs would be found on land mammals. These discoveries strongly confirm the theory that whales and dolphins evolved from earlier limbed, land-dwelling species. Why? Because, while atavistic limbs aren’t probable given the truth of that theory, they’re still far more probable than they would be if whales and dolphins weren’t the descendants of such limbed creatures.
The Mars face, on the other hand, provides an example of weak or non-existent evidence. Yes, if there was an ancient Martian civilisation, then we might discover what appeared to be a huge face built on the surface of the planet. However, given pareidolia and the likelihood of face-like features being thrown up by chance, it’s about as likely that we would find such face-like features anyway, even if there were no alien civilisation. That’s why such features fail to provide strong evidence for such a civilisation.
So now consider our report of the UFO hanging over the nuclear power construction site. Are several such cases involving multiple witnesses and backed up by some hard evidence (eg, a radar blip) good evidence that there are alien craft in our skies? No. We should expect such hard-to-explain reports anyway, whether or not we’re visited by aliens. In which case, such reports are not strong evidence of alien visitors.
Being sceptical about such reports of alien craft, ghosts or fairies is not knee-jerk, fingers-in-our-ears naysaying. It’s just recognising that, though we might not be able to explain the reports, they’re likely to crop up occasionally anyway, whether or not alien visitors, ghosts or fairies actually exist. Consequently, they fail to provide strong evidence for such beings.
3. Extraordinary claims require extraordinary evidence
It was the scientist Carl Sagan who in 1980 said: ‘Extraordinary claims require extraordinary evidence.’ By an ‘extraordinary’ claim, Sagan appears to have meant an extraordinarily improbable claim, such as that Alice can fly by flapping her arms, or that she can move objects with her mind. On Sagan’s view, such claims require extraordinarily strong evidence before we should accept them – much stronger than the evidence required to support a far less improbable claim.
Suppose for example that Fred claims Alice visited him last night, sat on his sofa and drank a cup of tea. Ordinarily, we would just take Fred’s word for that. But suppose Fred adds that, during her visit, Alice flew around the room by flapping her arms. Of course, we’re not going to just take Fred’s word for that. It’s an extraordinary claim requiring extraordinary evidence.
If we’re starting from a very low base, probability-wise, then much more heavy lifting needs to be done by the evidence to raise the probability of the claim to a point where it might be reasonable to believe it. Clearly, Fred’s testimony about Alice flying around the room is not nearly strong enough.
Similarly, given the low prior probability of the claims that someone communicated with a dead relative, or has fairies living in their local wood, or has miraculously raised someone from the dead, or can move physical objects with their mind, we should similarly set the evidential bar much higher than we would for more mundane claims.
4. Beware accumulated anecdotes
Once we’ve formed an opinion, it can be tempting to notice only evidence that supports it and to ignore the rest. Psychologists call this tendency confirmation bias.
For example, suppose Simon claims a psychic ability to know the future. He can provide 100 examples of his predictions coming true, including one or two dramatic examples. In fact, Simon once predicted that a certain celebrity would die within 12 months, and they did!
Do these 100 examples provide us with strong evidence that Simon really does have some sort of psychic ability? Not if Simon actually made many thousands of predictions and most didn’t come true. Still, if we count only Simon’s ‘hits’ and ignore his ‘misses’, it’s easy to create the impression that he has some sort of ‘gift’.
Confirmation bias can also create the false impression that a therapy is effective. A long list of anecdotes about patients whose condition improved after a faith healing session can seem impressive. People may say: ‘Look at all this evidence! Clearly this therapy has some benefits!’ But the truth is that such accumulated anecdotes are usually largely worthless as evidence.
It’s also worth remembering that such stories are in any case often dubious. For example, they can be generated by the power of suggestion: tell people that a treatment will improve their condition, and many will report that it has, even if the treatment actually offers no genuine medical benefit.
Impressive anecdotes can also be generated by means of a little creative interpretation. Many believe that the 16th-century seer Nostradamus predicted many important historical events, from the Great Fire of London to the assassination of John F Kennedy. However, because Nostradamus’s prophecies are so vague, nobody was able to use his writings to predict any of these events before they occurred. Rather, his texts were later creatively interpreted to fit what subsequently happened. But that sort of ‘fit’ can be achieved whether Nostradamus had extraordinary abilities or not. In which case, as we saw under point 2 above, the ‘fit’ is not strong evidence of such abilities.
5. Beware ‘But it fits!’
Often, when we’re presented with strong evidence that our belief is false, we can easily change our mind. Show me I’m mistaken in believing that the Matterhorn is near Chamonix, and I’ll just drop that belief.
However, abandoning a belief isn’t always so easy. That’s particularly the case for beliefs in which we have invested a great deal emotionally, socially and/or financially. When it comes to religious and political beliefs, for example, or beliefs about the character of our close relatives, we can find it extraordinarily difficult to change our minds. Psychologists refer to the discomfort we feel in such situations – when our beliefs or attitudes are in conflict – as cognitive dissonance.
Perhaps the most obvious strategy we can employ when a belief in which we have invested a great deal is threatened is to start explaining away the evidence.
Here’s an example. Dave believes dogs are spies from the planet Venus – that dogs are Venusian imposters on Earth sending secret reports back to Venus in preparation for their imminent invasion of our planet. Dave’s friends present him with a great deal of evidence that he’s mistaken. But, given a little ingenuity, Dave finds he can always explain away that evidence:
‘Dave, dogs can’t even speak – how can they communicate with Venus?’
‘They can speak, they just hide their linguistic ability from us.’
‘But Dave, dogs don’t have transmitters by which they could relay their messages to Venus – we’ve searched their baskets: nothing there!’
‘Their transmitters are hidden in their brain!’
‘But we’ve X-rayed this dog’s brain – no transmitter!’
‘The transmitters are made from organic material indistinguishable from ordinary brain stuff.’
‘But we can’t detect any signals coming from dogs’ heads.’
‘This is advanced alien technology – beyond our ability to detect it!’
‘Look Dave, Venus can’t support dog life – it’s incredibly hot and swathed in clouds of acid.’
‘The dogs live in deep underground bunkers to protect them. Why do you think they want to leave Venus?!’
You can see how this conversation might continue ad infinitum. No matter how much evidence is presented to Dave, it’s always possible for him to cook up another explanation. And so he can continue to insist his belief is logically consistent with the evidence.
But, of course, despite the possibility of his endlessly explaining away any and all counterevidence, Dave’s belief is absurd. It’s certainly not confirmed by the available evidence about dogs. In fact, it’s powerfully disconfirmed.
The moral is: showing that your theory can be made to ‘fit’ – be consistent with – the evidence is not the same thing as showing your theory is confirmed by the evidence. However, those who hold weird beliefs often muddle consistency and confirmation.
Take young-Earth creationists, for example. They believe in the literal truth of the Biblical account of creation: that the entire Universe is under 10,000 years old, with all species being created as described in the Book of Genesis.
Polls indicate that a third or more of US citizens believe that the Universe is less than 10,000 years old. Of course, there’s a mountain of evidence against the belief. However, its proponents are adept at explaining away that evidence.
Take the fossil record embedded in sedimentary layers revealing that today’s species evolved from earlier species over many millions of years. Many young-Earth creationists explain away this record as a result of the Biblical flood, which they suppose drowned and then buried living things in huge mud deposits. The particular ordering of the fossils is supposedly accounted for by different ecological zones being submerged one after the other, starting with simple marine life. Take a look at the Answers in Genesis website developed by the Bible literalist Ken Ham, and you’ll discover how a great deal of other evidence for evolution and a billions-of-years-old Universe is similarly explained away. Ham believes that, by explaining away the evidence against young-Earth creationism in this way, he can show that his theory ‘fits’ – and so is 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.
[my italics]
According to Ham, young-Earth creationists and evolutionists do the same thing: they look for ways to make the evidence fit the theory to which they have already committed themselves:
Evolutionists have their own framework … into which they try to fit the data.
[my italics]
But, of course, scientists haven’t just found ways of showing how the theory of evolution can be made consistent with the evidence. As we saw above, that theory really is strongly confirmed by the evidence.
Any theory, no matter how absurd, can, with sufficient ingenuity be made to ‘fit’ the evidence: even Dave’s theory that dogs are Venusian spies. That’s not to say it’s reasonable or well confirmed.
Of course, it’s not always unreasonable to explain away evidence. Given overwhelming evidence that water boils at 100 degrees Celsius at 1 atmosphere, a single experiment that appeared to contradict that claim might reasonably be explained away as a result of some unidentified experimental error. But as we increasingly come to rely on explaining away evidence in order to try to convince ourselves of the reasonableness of our belief, we begin to drift into delusion.
