Draft for comments please

Here is half of a first rough draft of a chpt for someone else’s book. The theme is Humanism: science, reason and skepticism. Comments please…

What are science and reason?

Humanists expound the virtues of science and reason. But what are science and reason? And we should we think it wise to rely on them?

By science, I shall mean that approach to finding out about reality based on the scientific method. This is a method that was fully developed only a few hundred years ago. Science, as I’ll use the term here, is a comparatively recent invention, its development owing a great deal to 16th and 17th Century thinkers such as the philosopher Francis Bacon (1561-1626).

So what is the scientific method? Here’s a rough sketch. Scientists collect data through observation and experiment. They formulate hypotheses and broader theories about the nature of reality to account for what they observe. Crucially, they then test their theories. Scientists derive from their theories predictions that can be independently checked by observation.

Take for example, the old Aristotelean theory that all heavenly objects revolve around the earth. With the aid of an early telescope Galileo observed that Jupiter had moons that revolved around it, not the Earth. He thereby falsified Aristotle’s theory.

Theories can also be confirmed by observation – if you can derive from your theory a prediction that is unlikely to be true if the theory is false, then discovering that the prediction is true confirms your theory. For example, to explain the erratic orbit of Uranus given Newton’s Laws of Gravitation, astronomers posited the existence of an as yet undiscovered planet. From their theory, they predicted the location of this new planet, looked, and discovered a planet there (Neptune). Because it was unlikely that there should happen to be a planet at that spot if their theory was false, this observation strongly confirmed their astronomical theory.

Systematic and rigorous testing, rooted in what we can directly observe of the world around us, is the cornerstone of the scientific method. Emphasis is placed on formulating theories and predictions with clarity and precision, focussing, wherever possible, on phenomena that are mathematically quantifiable and that can be objectively and precisely measured, e.g. using a calibrated instrument.

Non-scientific approaches to rationally assessing beliefs

The scientific method is a powerful tool, but surely not every reasonable belief is arrived at by means of it. People held beliefs, and held them reasonably, long before the development of the scientific method.

Suppose someone tells me they have an elephant in their trouser pocket. Given the absence of any large bulges in their trousers, it’s entirely reasonable for me to reject this claim: there’s no elephant there. True, I make this judgement on the basis of what I observe, but this could hardly be called science – certainly not as I have defined the term above. We engaged in this sort of reasoning long before the development of the scientific method.

Let’s also remember that beliefs can also be supported or refuted by non-empirical means (that’s to say, without relying observation of the external world). Take mathematical truths, for example. That twelve times twelve is one hundred and forty-four is something you can establish from the comfort of your armchair – by reason alone. So too can other conceptual truths. It’s possible, for example to figure out whether my great grandmother’s uncle’s grandson is my second cousin once removed by just unpacking these concepts and examining the logical relations that hold between them. Again you can do this from the comfort of your armchair. No empirical investigation or testing is required.

Rather more significant conceptual discoveries can also be made from your armchair. Galileo famously refuted the Aristotelean view that two balls of differing mass will consequently fall at different speeds by means of a thought-experiment. Galileo asks us to imagine that the two balls are now connected by a chain. This combination of objects will now have an even greater combined mass, and so, given Aristotle’s theory, should fall faster than they did individually. Yet, given Aristotle’s theory, the less massive ball should function as a brake on the more massive ball, and so the chained balls should fall more slowly than did the more massive ball. Galileo could demonstrate, from the comfort of his armchair, without applying the scientific method, that Aristotle’s view generates a logical contradiction, and so cannot be true.

So, even while acknowledging that science, as I have characterized it here, is an extraordinarily powerful tool, we should also acknowledge that non-scientific, but nevertheless rational, methods also have their place when it comes to arriving at reasonable belief – including armchair methods. Science is merely one way – albeit a particularly important way – of arriving at reasonable belief.

What’s so great about reason and science?

Why should we favour the application of science and reason over other methods of arriving at beliefs, such as picking beliefs at random, or believing what we would like to be true, or believing what a psychic tells us?

Advocates of science often point to its extraordinary track record. We have only had the fully-developed scientific method for about 400 years – just five of my lifetimes. Yet in that short time it has utterly transformed our understanding of the world and the character of our lives. Four hundred years ago, Westerners believed they inhabited a universe just a few thousand years old, created in just a few days. They possessed almost no effective medicine and relied on horses or their own legs to get around. Through science we have discovered the universe is about 13.75 billion years old, have developed electricity, computers, unravelled the genetic code, developed vaccines and visited the moon.

True, scientific theories are overturned, and of course it may turn out that many of our best current theories are mistaken. Scientific theories are often adopted only tentatively and cautiously. Nevertheless, the scientific method has allowed us to overturn a great many myths and make enormous progress in understanding the nature of the universe we inhabit and our place within it. While what scientists assert is sometimes dismissed by critics as being “just a theory” (that is often said about the theory of evolution, for example), a great many scientific theories are extraordinarily well-confirmed. Yes it is possible that any given scientific claim, no matter how well-confirmed, might turn out to be false. But “possible” does not mean probable. When it comes to such scientific claims as that the Earth goes round the sun, or that life has existed – and indeed evolved – on the surface of this planet for more than just a few thousand years, they are now confirmed to such an extent that it is ludicrous to suggest they might be false.

Science, and reason more generally, are valued by humanists because of their ability to reveal, or at least get us closer to, the truth. Science and reason offer us truth-sensitive ways of arriving at beliefs.

Humans have a remarkable capacity for generating false but nevertheless impressively rich and seductive systems of belief. Almost every culture has evolved belief in invisible and magical beings, such as ghosts, spirits, demons or gods. Belief in the magical power of objects, in psychic powers, in precognition and end-of-world prophecies, remains widespread across much of the developed world. Belief in non-supernatural but nevertheless bizarre phenomena such as Nessie (the Loch Ness monster), alien-piloted flying saucers, alien abduction, conspiracy theories involving 9/11, the moon landings and the Holocaust, and alternative histories involving ancient alien architects is also rife. Our vulnerability to such false belief systems is well-documented. Even intelligent, well-educated people are vulnerable (Sir Arthur Conan Doyle, creator of that quintessentially rational fictional character Sherlock Holmes, believed in fairies, and was successfully hoaxed by two little girls who faked photographs of fairies with their box brownie camera).

Very many of these beliefs systems are rooted in testimony – reports, supposedly originating with eyewitness to events such as miracles, amazing cures, precognition, and bizarre, seemingly piloted objects in our skies.

One particularly striking series of reports concerned an object that appeared over the building site of a new nuclear power station back in 1967. Sanitation workers claimed they saw a large lighted object. Then a guard confirmed the sighting. The police arrived. An officer said the object “was about half the size of the moon, and it just hung there over the plant. Must have been there nearly two hours.” The object vanished at sunrise. The next night, the same thing occurred. The county deputy sheriff described seeing a “large lighted object”. An auxiliary police officer reported “five objects – they appeared to be burning. An aircraft passed by while I was watching. They seemed to be 20 times the size of a plane.” A Wake county magistrate who arrived on the scene claimed to witness “a rectangular object, looked like it was on fire… We figured it about the size of a football field. It was huge and very bright.” There was also hard evidence evidence to support these reports – local air traffic control also reported an unidentified blip on their scope.

Local news reporters finally arrived to investigate. The object appeared again at five a.m. When they attempted to chase the object in a car, they found they couldn’t catch up with it. Eventually, they pulled up and looked at the object through a long camera lens. “Yep, that’s the planet Venus alright,” noted the photographer.

Though this might not strike many of us as remotely likely, the various eyewitnesses to the large illuminated object hanging over the nuclear plant had seen nothing more than Venus. Venus is one of the most common sources of UFO reports. That anomalous radar blip was just a coincidence.

What’s interesting about this case is that, if it had not been solved by a bit of good luck – by those reporters showing up and publicizing the truth – it could very easily have gone down in the annals of UFO-logy as one of the great unsolved cases. UFO buffs would no doubt have seized upon it and said: “Here we have, sincere, multiple, trained eye-witnesses – workers, policemen, a deputy sheriff and a magistrate. They have produced largely consistent reports of a bizarre lighted object hanging over the plant. They have no motive to give false reports (indeed, such officials are often hesitant and embarrassed about giving such reports). It’s absurd to suppose they might all have just have just seen a planet. Don’t forget their claims were supported by hard evidence in the form of that radar blip. Surely the best explanation of these reports is that there really was a large lighted object hanging over that plant.”

Fortunately, we did get lucky and now know the truth. What this case illustrates is that human beings are remarkably prone to generating such false reports, and for a very wide variety of reasons. This particular example was produced by an optical illusion and a coincidence (the radar blip), but take out a subscription to Skeptical Inquirer (published in the US) or The Skeptic Magazine (UK) and you will discover that such amazing reports are constantly being explained by reference to a wide variety of far-too-easily-dismissed-or-overlooked mundane mechanisms.

The moral is: clearly, a significant number of such otherwise-unexplained reports are going to be made anyway, whether or not there really are any visiting alien spacecraft, psychics, or miracles. But then the existence of such testimony is not good evidence that such phenomena are real.

True, it’s often reasonable to take testimony at face value. If Ted and Mary, a couple I know well and have learned to trust, tell me that a man called Bob visited them last night, I’ll rightly take their word for it. But if Ted and Mary add that Bob flew round the room by flapping his arms, died and then came back to life, then it’s no longer reasonable for me to just take their word for it that these things happened. When it comes to such claims, we should raise the evidential bar much higher because we know that such reports – including even reports that appear very hard to explain in mundane terms – are going to be made from time to time anyway, whether or not there’s any truth to them.

One variety of false belief to which we’re particularly prone is belief in hidden agency – in hidden beings with their own beliefs and aims – where in truth there are none. We’re particularly quick to appeal to hidden agents when presented with significant questions to which we lack answers. When we could not understand why the heavenly bodies moved in the way they do, we supposed that they must be other agents – gods. When we could not explain natural diseases and disasters we supposed they must be the work of malevolent agents, such as witches or demons. When we couldn’t explain why plants grew, or the seasons rolled by, we supposed that there must be sprites, or nature spirits, or other agents responsible for these things. Was a result of this natural tendency to reach for mysterious hidden agents when faced with such mysteries, we have populated our world with an extraordinary range of hidden and mysterious beings and developed extraordinarily rich and complex narratives about them.

Those who are broadly skeptical about such claims often refer to them somewhat disparagingly as “woo”. As we have seen, woo claims – or W-claims, as I’ll call them – are obviously a diverse bunch, involving psychic powers, alien abduction, cryptozoology (big foot, Nessie, etc.) past life regression, end-times prophecies, miracles, ghosts, fairies, demons and gods. They are claims with which we are peculiarly fascinated (which explains why they feature so much in tabloid newspapers, fiction, films, and so on), and to which we are very easily drawn. Clearly, while not all may be false, very, many are. Very many have been debunked. Many are mutually incompatible (many god claims, for example, are mutually exclusive – a great many of them must be false).

The humanist position is that we should take a skeptical attitude towards reports of miracles, alien visitation, and so on. We should not assume they are false (some may not be). However, humanists, as a rule, believe we should subject such reports to close rational and scientific scrutiny, and acknowledge that our inability to find a plausible-sounding but mundane explanation for such reports is, as it stands, not good evidence that they are true.

Notice that reason I am giving here for being skeptical about such reports is not that what is reported is impossible or even improbable (some religious insist that if there is a God, then his performing miracles is neither impossible nor improbable; thus skepticism about religious miracles based on the assumption that miracles are impossible or improbable just presupposes there’s no God). It’s not impossible, or even very improbable, that there exist bizarre and as yet undiscovered creatures that humans occasionally glimpse. The reason we should be pretty skeptical about such cryptozoological reports (Nessie, Big Foot, and so on) is not that such creatures are impossible, or even improbable, but that such reports are going to be made fairly regularly anyway whether or not they’re true.

The scientist and humanist Carl Sagan once said, “Extraordinary claims require extraordinary evidence”. Under the heading “extraordinary claims” Sagan would certainly include what I am calling W-claims. And Sagan is correct about W-claims – we really should raise the evidential bar much higher than usual before accepting them. Why? If for no other reason than that we have an extraordinary track record of unreliability when it comes to making them.

The world is chock full of competing W-claims, including religious claims. They are claims to which we are both easily drawn and peculiarly vulnerable. If we step out into the marketplace of ideas as willing to accept someone’s testimony that they have psychic powers or a direct line to God as that they had baked beans for lunch, and our heads are soon going to fill up with nonsense. If we value truth, it’s important we apply science and reason as best we can – as, if you like, a filter. False beliefs may still get through, but subjecting claims – especially W-claims – to rational and/or scientific scrutiny before accepting them gives us our best chance of having mostly true beliefs.

Let’s now turn to some examples of some specifically religious claims that have failed to pass rational and/or scientific scrutiny.

C Science as a threat to religious belief

Many religious claims have been falsified, or at least shown to be rather less than well-founded, as a result of scientific investigation. Here are few examples:

Young Earth Creationism. The Young Earth Creationists (YEC) believe that the entire universe was created by God approximately 6,000 years ago (certainly less than 10,000 years ago). Their estimate is based on Biblical sources. In the 17th Century, using the Old and New Testaments as his source, Bishop James Ussher calculated that the moment of creation during the night before the 23rd October 4004 BC. Young Earth Creationism has since been empirically falsified in many ways by the cosmological, geological, biological, archeological and various other sciences. 

An Earth-centered universe. Back in the early 17th Century, the dominant cosmology, endorsed by the Catholic Church, placed the Earth at the centre of the universe. The other heavenly bodies, including the sun, revolved around it. This view was also supported by scripture. For example, Psalms 96:10 says “the world is established, it shall never be moved.” And in Joshua 10:12-13, Joshua commands the sun to “stand still”, which suggests that the sun moves. This cosmology was rejected by Galileo (who was accused of rejecting it without proof, and was subsequently shown the instruments of torture and condemned to house imprisonment as a result). Science has, of course established, beyond any reasonable doubt, that Galileo was right and the previously dominant religious view wrong.

The power of prayer. Many people believe in the power of petitionary prayer. For example, it is often claim that praying for people with a disease improves their chances of recovery. Yet recent rigorously-conducted large-scale scientific studies do not support this view. Indeed they undermine it. In 2006, American Heart Journal published the results of a $2.4 million experiment involving 1,802 heart-bypass patients, conducted under the leadership of Herbert Benson, a specialist who also believes in the medical efficacy of petitionary prayer. The results were unambiguous: prayer had no beneficial effect. A similar large-scale trial of patients undergoing angioplasty or cardiac catheterization also revealed prayer had no effect. That prayer has beneficial medical effects is a religious belief that can be scientifically tested. Tests strongly suggest it’s false.