Pseudoscience - What is not science?

A wonderful place to pursue this topic in more detail is the website by The Committee for Skeptical Inquiry.

In the previous sections on science and knowledge, you've read my thoughts on science and what we can learn from it. As already stated, science doesn't provide final or complete answers. But of course, we'd all like a little certainty in our lives, so it shouldn't be surprising that many people look beyond science to answer questions about the universe around them.

The result is interesting (to put it mildly). Thanks to modern science, we have revolutionized modern technology. As you read this, you're probably sitting at a computer hooked up to the internet, both of which are impressive examples of modern technology made possible by scientific discoveries. Clearly, science has done much to improve our quality of life and change it in many ways. And yet, despite all this, we live in a world full of strange and crazy ideas. It's ironic that many of these ideas fly in the face of science, and yet these days many of them propagate themselves over the internet, using the very tools science has made possible.

I'm talking about pseudoscience. I'll try and define it below, but let's start with a few of the more notorious examples: astrology, UFOs as alien spacecraft, creationism, and the Bermuda Triangle. The list is endless, because there's always money to be made by fooling people with new pseudoscientific ideas, so just when you stamp one out, more grow in its place, like mushrooms in a wet forest.

In general, pseudoscience imitates science at first glance, but upon more careful inspection falls short in some critical way. This definition is vague, and rather than try to improve it, it's probably better to look at how we can filter out pseudoscience when we encounter it. The best filter starts with Karl Popper's discussion of what constitutes a scientific statement. In general, any statement can fall into three categories:

  1. A statement which is falsifiable, but has not yet been falsified;
  2. A statement which is falsifiable, and has been shown to be false;
  3. A statement which is not falsifiable
Popper claims that a scientific statement must be falsifiable. A valid scientific statement must not yet have been proven false (1). Statements which cannot be proven false (3) are unscientific, and statements which can be proven false, even if they are scientific, are still invalid once they have been proven false (2).

Before proceeding, we should clarify what we mean when we say a statement has been proven false. If a claim is made that Cause A produces Effect B, and we test this claim, we can state that the claim has failed the test if we see no statistically meaningful evidence to support the relation between A and B. There are many ways this could happen even if the claim were actually true, but after many different tests, a lack of convincing evidence leads to the conclusion that the claim is without merit.

No measurement or experiment can be perfect, so every scientific result comes with an uncertainty. Suppose that we wish to measure the height of a 1 mm flea on top of a foot-long ruler (305 mm). If the uncertainty of each measurement is 1 mm, then sometimes we'll get 305 mm (no flea), sometimes we'll get 306 mm (1 flea), and sometimes we'll get 307 mm (two fleas!). If we conduct enough measurements, we'll even occasionally get 308 mm or 304 mm. One might be tempted to quote the latter result as evidence for negative fleas, but this is obviously silly.

Now, back to Cause A and Effect B. Suppose there is no relation whatsoever between them. In a well-designed experiment, we would get on average a correlation of zero, but with the uncertainty of the measurements thrown in, we would usually find small negative or positive correlations. Rarely would we get exactly zero (actually, never!). Occasionally, these fluctuations might even give a result that looked like reasonable proof by itself. Only in the context of the 100 or so other experiments that showed no evidence would it be clear that this one positive result was a statistical fluke.

Let's take astrology as an example. The key to astrology is the idea that the positions of the planets and constellations in the sky when a person is born can influence their personality, and this is straightforward to test. The consensus? There is no evidence to support the claim. This fact ought to close the book, but because astrology is a well-established pseudoscience, many people want to believe in it, and since there's much money to be made, astrology lingers on. People keep testing it, in the hopes that they will find a correlation where others haven't, and as expected, they occasionally do, even though it's never a strong correlation. People who want to believe will cling to these isolated cases despite the flood of evidence to the contrary.

Before moving on to our next example, we should consider the anecdote as evidence for or against a claim. Anecdotal evidence essentially consists of second-hand stories, or even worse, third-hand stories. When Person A tells Person B about something that happened to them, it may certainly be true, but it's very hard to verify, thus making anecdotes unscientific. What's worse, when people collect anecdotal evidence, they generally do so in a very haphazard way.

A good example of how people collect anecdotal evidence is the idea that more bad things happen when the Moon is full. You've probably heard that emergencies rooms are busier and police have to answer more calls during full Moons. Unfortunately, statistical studies don't back up these impressions. So why do people believe the full Moon spells trouble? Most, if not all, of us have a tendency to remember those events which reinforce our preconceived notions and forget the rest. So once we get an idea in our head, our memory serves as a filter for supporting evidence. That's why it's important to be disciplined when collecting evidence for or against an hypothesis. You have to save all of the data and be careful.

Anecdotal evidence is dangerous. It cannot be falsified. It is usually collected in a haphazard manner, and in many cases with a clear bias towards a prevailing belief. It would be much better to collect evidence like this in a directly verifiable manner, such as videotape (unedited, of course), or in an indirectly verifiable manner, using a set of rules which would allow someone else to obtain similar results at a different time.

The belief by many that UFOs offer proof of visits by extra-terrestrial beings is supported only by anecdotal evidence. These UFO sightings cannot be duplicated or tested in the lab, although if witnesses provide details about times, places, directions, and other clues, it is often possible to determine what they actually saw. The cases which remain mysterious, however, are not proof of anything. They remain mysteries. Occasionally, more tangible evidence appears in the form of photographs or videotape, and this usually makes the explanation more easy to come by, even if it turns out to be a hoax or fraud. The bottom line is that we don't have any scientific evidence that extra-terrestrials are visiting Earth.

The UFO issue raises one important point to be addressed. Frequently proponents of UFOs as alien spacecraft, when a sighting cannot be explained by known phenomena, will state that if nothing else explains their sighting, then their claim must be correct. Lack of proof for one claim cannot be construed as support for an alternative claim, as though those are the only two explanations possible in the Universe. One would be equally correct with this logic if one argued that all UFO sightings which remain unexplained are proof of giant floating cockroaches in disguise. Pseudoscience makes frequent use of this tactic, arguing that some pet theory must be correct since no successful alternative has been proposed.

One should also beware of the argument from authority. Just because the respected Sir Joe Blow believes it doesn't make it true. Respectable people have been wrong before, and they will be wrong again. Just because we want something to be true doesn't make it so.

The best filter for pseudoscience is the simple reminder that no idea should be accepted without reasonable evidence. And what's more, as Carl Sagan puts it, "Extraordinary claims require extraordinary proof." In other words, an idea which would invalidate some portion of existing scientific knowledge won't just require some evidence to support it; it's going to require a lot of evidence.

Whenever someone tells me something I can't prove or disprove, I just think of the invisible floating pink elephants... As you are reading this, right now, I can assure you that the room about you is filling up with invisible floating pink elephants. You can't touch them; you can't smell them; since they're invisible, you certainly can't see them. But they're there, you just have to take my word for it. So why don't you believe me?

Statements in the past with just as much evidence to support them have managed to collect their followers. As just one frightening example, think back to the 39 members of the Heaven's Gate cult who committed suicide in Rancho Sante Fe north of San Diego in 1997. Marshall Applewhite told his followers that if they killed their physical selves, they would ascend to an alien spacecraft hiding behind Comet Hale Bopp where the extra-terrestrials would lead them to their new lives off of planet Earth. It's remotely possible that they really did leave the planet and move on to a higher plane; after all I don't have any evidence against this claim. But it's a bit more likely that they're just dead. Either way, a healthier dose of critical thinking skills, and they'd still be alive and on the planet.

If you choose to go through life without using this filter, the choice is yours. A claim for which there is no evidence may actually be right, but it could just as easily be wrong. In fact, it's far, far, more likely to be wrong. I don't wish to hammer away at thinking which could be described as metaphysical, spiritual, or even religious. I only wish to emphasize the dangers of crossing the line from the world of the verifiable to the world of the unverified or unverifiable. By not applying critical thinking skills, you have made yourself gullible. Believing in astrology (or UFO abductions, or telepathy, or the healing powers of crystals, take your pick) may not do an individual much harm, but uncritical thinking does harm society. Do you really want someone this gullible sitting on your jury if you've been falsely charged with a criminal offense? Or voting for your future leaders? It is worth noting that con artists often target people affiliated with pseudoscientific groups. There is nothing better in a mark than a lack of critical thinking skills.

Just think of all the money spent today to perpetuate the UFO myth: newsletters, conferences, investigation after investigation of yet another UFO sighting, books, TV programs, movies, and even group counseling sessions for supposed abductees. Other pseudosciences suck up people's money similarly. Just suppose that money were diverted to scientific research. Better cancer treatments, better understanding of the weather, or earthquakes, or how the Solar System formed... If I had just a small piece of the money spent on UFOs to conduct my own research, I'd be one happy astronomer! And think of all the money diverted to counter these pseudoscientific views. I'm glad we spend this money, because if we didn't, there'd be even larger hordes of the gullible and superstitious. But wouldn't it be nice if we didn't have to?

For more reading, see the separate pages on:

Other pseudosciences which I might eventually get around to discussing:


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Last modified 4 June, 2010. © Gregory C. Sloan.