To distinguish science from pseudoscience the crux is falsifiability (i.e., refutability), not verifiability. For example, for years astronomers had predicted the physics of a collision between two neutron stars. But it had not been possible to verify it by the simple fact that, until very recently, the phenomenon had not been observed in radio telescopes. And there are astronomical hypotheses that cannot yet be verified due to lack of observation. It may be so long without these other phenomena being observed that, when the day comes, we would already be dead.
The idea is to elaborate a solid principle of demarcation that will serve us today to distinguish between true and false science. In addition, in a borderline area of research, such as the shroud of Turin, there is no lab test of ‘Christness’ as there are, say, tests to detect a human pregnancy. What does it even mean ‘scientific verification’ that a cloth covered the body of Jesus? The most we can do is date the linen with reliable radiometric tests. If the results come out after the 1st century of our era, it is ruled out that it was ‘the shroud of Christ’. The point is that this strategy is not verification but falsification of the 1st century hypothesis.
It may not be easy to understand the concept of falsifiability if we read philosophers of science directly. But it is easily understood when we read a pedagogue. The most didactic class I know of to understand the concept is that of the neurologist Terence Hines in the first chapter of his book Pseudoscience and the Paranormal, published the year in which the Carbon 14 tests were done on the shroud. I read it in 1990: the year I started reading texts from sceptics after five years of reading exclusively to parapsychologists and sindonologists.
The chapter, ‘The Nature of Pseudoscience’ from Hines’ book begins with the following words:
______ 卐 ______
What is pseudoscience? It’s difficult to come up with a strict definition. In the real world things are not clearly delineated but surrounded by gray areas that doom any hard definition. As the term implies, a pseudoscience is a doctrine or belief system that pretends to be a science. What distinguishes pseudoscience from real science? [Some authors] have discussed criteria for separating real science from pseudoscience and for helping to decide whether a new claim is pseudoscientific.
The most common characteristic of a pseudoscience is the nonfalsifiable or irrefutable hypothesis. This is a hypothesis against which there can be no evidence—that is, no evidence can show the hypothesis to be wrong. It might at first seem that such a hypothesis must be true, but a bit of reflection and several examples will demonstrate just the opposite. Consider the following hypothesis: “I, Terence Michael Hines, am God incarnate, and I created the universe thirty seconds ago.” Now, you probably don’t believe this hypothesis, but how would you go about disproving it? You could argue, “You say you created the universe thirty seconds ago, but I have memories from years ago. So, you’re not God.” But I reply, “When I created the universe, I created everyone complete with memories.” We could go on like this for some time and you would never be able to prove that I’m not God. Nonetheless, this hypothesis is clearly absurd!
Creationists, who believe that the biblical story of creation is literal truth, often adopt a similar irrefutable hypothesis. They claim that the world was created less than ten thousand years ago. As will be seen in chapter twelve, vast amounts of physical evidence clearly refute this claim. All one has to do is point to something older than ten thousand years. Backed into a corner by such evidence, creationists often rephrase the creationist hypothesis in an irrefutable form. They explain the clear geological and fossil evidence that dates back millions of years by claiming that God put that evidence there to test our faith. An alternative version is that the evidence was manufactured by Satan to tempt us from the true path of redemption. No evidence can refute either of these versions of the hypothesis, since any new piece of geological or fossil evidence can be dismissed as having been placed there by God or Satan. This does not make the hypothesis true—it just makes it nonfalsifiable. Such a hypothesis contributes nothing to our understanding of the physical world.
Another example of an irrefutable hypothesis comes from a doctrine not usually considered a pseudoscience (but which meets the criteria, as will be seen in chapter five)—psychoanalysis. Sigmund Freud believed that all males had latent homosexual tendencies, but that in most males these tendencies were repressed. Clearly, homosexual males have homosexual tendencies. But what about heterosexual males? To determine whether the hypothesis that all males have repressed homosexual tendencies is false, you could give some sort of test for homosexual tendencies. What if you failed to find such tendencies? The standard Freudian reply is that the tendencies have been so completely repressed that they don’t show up on the test. Given this irrefutable hypothesis, no test could show that heterosexual males don’t have latent homosexual urges. No matter how sensitive the test, the reply can always be made that the urges are so deeply repressed that they don’t show up on the test.
Those who are skeptical about pseudoscientific and paranormal claims are frequently accused of being closed-minded in demanding adequate evidence and proof before accepting such a claim. But who is really being closed-minded? As a scientist, I can specify exactly the type of evidence that would be required to make me change my mind and accept the reality of astrology, UFOs as extraterrestrial spacecraft, or any other topic considered in this book. But the believer, who likes to paint him or herself as open-minded and accepting of new possibilities, is actually extremely closed-minded. After all, the irrefutable hypothesis is really saying “There is no conceivable piece of evidence that will cause me to change my mind!”
That is true closed-mindedness.