I remember during my teenage years there was a sudden craze for so-called “Magic Eye” pictures. These appeared at first glance to be featureless pages of random dots, until you focussed your eyes in just the right way and a remarkable three-dimensional image jumped out. The image seemed so real that you could reach out and pick it up in your hand, but when you tried to do so the illusion vanished. “Magic Eye” pictures work by tricking the brain into thinking that it sees a three-dimensional object. They do this by cleverly positioning seemingly random dots in a way that hijacks the brain’s depth perception and forces it to see something that isn’t physically there.
Much the same process is at work in more conventional optical illusions. Is it a vase or two faces? Is the front face of the cube pointing to the left or the right? Are those really perfect circles or are they squashed in one direction? I’m sure you know all the examples above, and plenty more. One of the oldest optical illusions is the familiar picture of two lines capped with arrows. On one line the arrows point inwards, and on the other they point outwards. Which of the two lines is the longest? Well it seems obvious – it’s the one with the arrows pointing inwards. No, the puzzle smugly announces, they’re both the same length! The first time you see that trick you’re amazed and immediately reach for a ruler. The second time, although the feeling is still there, you now know better and you confidently state that the lines are the same length, even though your brain is screaming at you that they are not. You have learned a flaw in the way your brain works. A trivial flaw, admittedly, but a reliable and repeatable flaw nonetheless. And you’ve learned what it feels like to experience a strong instinct that appears clear and convincing but which is also provably wrong. You were aware that your brain was deceiving you, you accepted that your instinct was wrong and you overruled it.
Congratulations, you now know what it’s like to be a skeptic!
Optical illusions work so well and they have such a predictable and universal effect, because just like the “Magic Eye” pictures they tap into our brain’s internal short-cuts. These are features of every single healthy brain on the planet, regardless of background, education, race or gender. And these short-cuts are not evidence that our brains are broken – in fact, quite the opposite, they demonstrate that our brains are working well and are highly efficient. They show that our brain has found clever ways to deduce as much information as possible about the world around us from the minimal information that it receives. Our brains often have to make “best guesses” in order to build up a coherent picture of that world, and they do this literally every waking second of your life. Your entire experience of the world around you is a construct formed inside the brain from insufficient data, using known short-cuts and based on best-guess approximations.
Is it a bird? Is it a plane? No, it’s Superman! We all understand that misunderstanding, despite the orders of magnitude difference in size between a bird, a man (albeit one from Krypton) and an aircraft. We understand that angular size (which is the only measurement directly accessible to the brain) cannot tell us absolute size unless we also know the distance to the object in question. Small objects nearby look identical to similarly-shaped but much larger objects proportionately further away. It’s a huge problem in Astronomy, where we can’t just get a tape measure billions of light years long and measure how far away a distant galaxy really is! To some extent Astronomers solve this challenge in the exact same way that our brains do innately – we find a way of knowing what type of object we’re looking at, and then we know how big (or bright) it really is, we can compare that with how big (or bright) it appears to be, and we can break down the ambiguity. When you see an unknown object moving across the sky, your brain is internally resolving the same size/distance ambiguity based on simple rules. If the object we’re watching seems to be moving in a constant, straight line then it’s probably a plane a long way away. If it’s moving more erratically, swerving, changing in altitude, then it’s probably a bird close by. If it’s throwing trucks around and firing lasers out of its eyes, then it’s probably Superman.
The brain is able to break down this size/distance ambiguity by making a guess based on experience. This is just one of a vast number of similar short-cuts, or “heuristics”, that the brain makes in order to make sense of the world. Every single one of them has a valid use, and in most cases it would be impossible to function without them, but every single one of them also exposes the brain to the possibility of making errors of judgement or, more worryingly, of being deliberately manipulated into experiencing something that is not real. Optical illusions are a particularly amusing and harmless case but there are other more malicious examples, such as irrational phobias. It makes sense to be cautious of deadly animals, but it doesn’t make sense to be scared of them when they’re on television. Or, for example, it is utterly irrational to be scared of spiders in the UK which are almost entirely harmless – yet many people are still so terrified of them that they can’t even enter a room in which a tiny, perfectly benign arachnid has been seen. The capacity to be terrified by spiders is universal, and very deeply rooted in the depths of our brains.
Another example might be the phenomenon of addiction. If our brain finds something pleasurable then it tends to encourage us to do it again, yet we all know how that can go disastrously wrong. Our brains evolved in a time when food was scarce, where enjoying highly energy-rich fatty, sugary foods was a good way to get us to eat as many of them as we could whenever we were lucky enough to find such a rare treat. Nowadays it’s less helpful, leading to obesity, heart disease, tooth decay and diabetes amongst other undesirable medical conditions.
More sinister sides of humanity also often rest on the deep innate responses of our brain. For example, we tend to judge people who are most like us to be the most trustworthy, and are naturally suspicious of those who are different. We also tend to spot patterns where none really exist because the our ancestors’ survival largely depended on being able to derive general rules from sparse examples. After all, the longer it takes you to learn that lions are dangerous, the less likely you are to survive long enough to have children and contribute your genes to the next generation. Pattern-matching is a highly evolved trait, and it is of immense value, even today. However, we are also afflicted with so-called “confirmation bias” – once we have a hypothesis about something we are more likely to pay attention to evidence that confirms our beliefs rather than disconfirms it, even if the disconfirming evidence is clear and undeniable. We see what we want to see, to some degree. You can easily see how these qualities lead to racism, sexism, and other societal wrongs.
I passionately believe that the best way to solve our civilisation-scale problems and to ensure the maximum possible flourishing and minimum possible suffering for all of humanity is to align our beliefs as closely as possible with the real world. We should accept reality, seek out truth, and make decisions based on the most accurate information possible. The reason why we have been able to eradicate some of the world’s worst diseases over the last century is because we gave up on the superstitious idea that diseases were evidence of evil spirits, witches or misalignment of mystical energy, and we moved past the pre-scientific ideas of “bad blood”, “balanced humors”, “chi” and “tainted air”. We kept looking until we found the truth – the existence of viruses and bacteria, and the complex biochemical workings of the human body – and that knowledge allowed us to create antibiotics, vaccines and effective palliative care which have saved billions of lives and prevented a literally unimaginable level of suffering.
As a skeptic, it is my strong view that this same process of inquiry should be applied to all aspects of human knowledge. We should seek out the truth as earnestly and honestly as possible, and we should use the knowledge we discover to maximise the flourishing of the entire human species in the same way that the discovery of viruses and bacteria kick-started the development of effective medicine. But to do so we have to come up with a way of searching for the truth and, more importantly, for recognising it when we find it. At a bare minimum, that mechanism absolutely has to cope with the fact that it will be operated by humans. That is to say, we have to realise that human beings are susceptible to the same cognitive shortcuts that we’ve been discussing so far, which can lead us into believing potentially damaging falsehoods. Our mechanism for searching out truths has to be able to recognise this challenge and overcome it, or our efforts will be spent in vain.
We all have beliefs, and those beliefs tend to change over time, which means we all necessarily have processes by which we develop new beliefs and abandon old ones. For some, that mechanism might be to let others decide their opinions for them. But most of us have other techniques for seeking out knowledge, which we believe are more likely to give us the “right” answers. When we’re young, our parents and teachers are the most important source of learning, possibly followed by television, our school friends and the Internet. After our formal schooling is over, we get to determine for ourselves how (or whether) we continue this search for knowledge.
We could, of course, continue to look for role models in whom to put our trust, choosing to believe everything they say. For many people, those role models might be newspaper editors, radio pundits, religious or community leaders or television personalities. I’m not saying that’s the worst possible solution because you might choose a good teacher and learn a lot of excellent information. But you might also choose a Jim Jones or a Charles Manson, or any one of a number of charlatans, frauds or megalomaniacs who peddle their delusions in such channels. To tell the difference between a fraud or charlatan, and a legitimately knowledgeable teacher, you really need some way of determining whether or not that person is telling you the truth. And that, of course, means that you need a way to determine truth that doesn’t actually involve asking the person you’re testing. So let’s put aside the possibility that you can just rely on other people for reliable knowledge – if we genuinely care about the truth, which we obviously should do, then blindly following a guru or teacher, no matter who plausible they may seem, simply isn’t going to work. By all means seek inspiration from inspirational people, but also submit the things they say to independent scrutiny to see how they match up to reality.
There are, of course, many other ways to search for the truth. I don’t want to go through them all, so to shortcut the whole process let’s just state at this point that if your mechanism for forming your personal beliefs does not explicitly deal with the obvious deficiencies in the human brain as I outlined above, then it is at best useless, and at worst actively harmful. If we have cognitive impairments that we know for a fact will lead us into incorrect deductions (e.g. confirmation bias) then any mechanism we have for discovering truths absolutely has to acknowledge those limitations and counteract them as effectively as possible. This is why we have tape measures, calculators and wristwatches – because the human brain is not very good at accurately determining the size of an object, multiplying large numbers together or measuring the passage of time. We use tools to make up for the deficiencies of our brains.
One other important deficiency that we should acknowledge is that our brains tend to form beliefs for emotional reasons rather than rational ones, and can easily be fooled into forming false beliefs either by accident or by the malicious use of trickery. People interested in making us think one way or the other generally have an excellent understanding of this. In fact, advertising is an entire subject devoted to precisely that one task, and we all know how effective it can be. Stage Magic is another example – magicians devote their lives to working out how humans can be deceived, and then they do precisely that right under your nose. There’s a reason why magicians are so often found debunking frauds and charlatans – because they have extensive first-hand experience of how easy it is to convince highly intelligent adult human beings of preposterously implausible claims merely using trickery and misdirection.
In summary, attempting to understand and explain the complexities of the Universe without correcting for the well-understood deficiencies of our unaided brains is like attempting to fly to the moon by climbing a hill and flapping your arms as fast as possible.
The good news is that for hundreds of years the smartest people on Earth have been thinking about exactly this problem, and they’ve come up with a solution which they are continuing to refine and improve all the time. It’s called Scientific Skepticism. The “Scientific” part comes from the application of the scientific method to analyse data from the world around us, to correct for biases and to learn new facts in a testable and quantifiable way. And the “Skepticism” part is all about enhancing this process by understanding how our brains can deceive us, and actively working to protect our investigations from the flaws and biases that we, as human beings, unwittingly introduce. The combination of both of these schools of thought is the best process we have for getting at the truth, and is therefore the best process we have for maximising human flourishing and minimising suffering. And that is why I support it, and why I spend so much effort getting as many people as possible to think the same way.
I have said this many times before, but it bears repetition: I can think of no aspect of human civilisation that would be worsened by the application of scientific skepticism, and many that would be immeasurably improved. Inequities that have plagued our species since prehistory would be entirely resolved by a political system based around a rational approach to truth claims. Scientific skepticism is the antidote to frauds and scams, it utterly disarms fakes and charlatans, it destroys pretty much all imaginable forms of negative discrimination, from racism and sexism to discrimination based on gender identity or sexual preference. Scientific skepticism would end all conspiracy theories, put a stop to dangerous anti-science movements like anti-vaccine activism and denial of anthropogenic global warming. It would remove in one fell swoop farcical creationist opposition to the teaching of established science in schools, and grief vampires like psychics, faith healers and mediums who prey on the emotionally compromised to benefit their own bank balances. It would remove from the market all bogus health products and techniques – those aggressively marketed by pharmaceutical companies as well as those peddled by fraudulent quacks and con-artists.
Scientific Skepticism is vital for the continued flourishing of the human race, and the good news is that everyone can develop the necessary skill set. Scientific Skepticism is a defence mechanism for our brains, an immune system protecting us from nonsensical or harmful ideas. It should be taught as an obligatory subject in schools and we should be enormously suspicious of those who fight against it. I cannot think of any rational reason why anyone should resist an effective mechanism for discovering truths, unless such a person benefits from spreading falsehood and disinformation – and such people can and should be opposed at every possible opportunity.
Some may worry that an application of Scientific Skepticism to their own beliefs would force them to make changes to their lives that may cause them emotional pain or uncertainty. This may be true – many delusional beliefs achieve their widespread adoption by providing a certain degree of comfort. I can offer two potential replies to this concern. Firstly, it is my strong belief that living under a comfortable delusion is not a path to psychological well being – having to fight every hour of every day, consciously or subconsciously, to ensure that your comfortable delusion doesn’t get derailed by inconvenient facts is a tiring and stressful activity, and rejecting that way of life gives a sense of relief and freedom that is profoundly beneficial. And secondly, I believe we are morally obliged to look to the future generations that will inherit this world after we are gone. My generation may have grown up with a bagful of comfortable delusions that many of us are reluctant to part with, but there is no reason why we should enforce that conspicuous mental slavery on our children, any more than we should force them to live with the bloodletting, plagues, racism, homophobia and ubiquitous violence of times gone by.
Scientific Skepticism is not a panacea – there are many things it cannot solve. Adopting a rational way of thinking won’t suddenly cure cancer or prevent earthquakes. But it will empower our society to end the injustices that have plagued the human race for millennia. It will make our lives immeasurably better while we strive together to solve the real problems that face humanity in the 21st Century and beyond.