Believing Bullshit: How Not to Get Sucked into an Intellectual Black Hole (10 page)

What about the theory of evolution? Can that be strongly confirmed? Yes. The theory is a theory of common descent. It says that contemporary species evolved from common ancestors in a tree-like manner, with contemporary species at the tips of the branches and the most common ancestor at the base of the trunk. If the theory is true, the sedimentary layers should reveal fossils arranged in a very specific order, consistent with such a tree-like structure.

In its fully developed form, the theory of evolution also says that birds and mammals developed fairly late in the history
of life, after the Devonian period. So the theory predicts that
not even one fossil of a bird or mammal will ever show up in the lower pre-Devonian deposits (which constitute over half the history of multicellular organisms
). As one scientist puts it: “Even
one
incontrovertible find of any pre-Devonian mammal [or] bird … would shatter the theory of common descent.”
¹⁰

These are both clear and precise predictions. They are also surprising predictions; for example, say the theory of evolution not true, and the flood theory were true instead. There would be no particular reason not to expect to find, among the countless thousands of fossils dug up each year, at least
one or two
avian or mammalian fossils in the pre-Devonian layers (Young Earth Creationists would not be remotely surprised if they did). Nor would there be any reason to expect fossils to line up in precisely the way predicted by the theory of common descent. Indeed, that the fossils should happen to line up precisely that way would be a gob-smacking coincidence if the theory weren't true.

So, in predicting that no such fossils will be found, the theory of evolution takes a very significant risk—which is why the fact that no such fossil has ever shown up very strongly confirms the theory of evolution. (And of course, this is just
one
example of how the theory of evolution is strongly confirmed. There are numerous others.)
¹¹

FALSIFICATION

Let's now turn from the notion of confirmation to that of falsification. What of the Young Earth Creationists' claim that their theory is not
falsified
by the fossil record? I am going to suggest that, not only is Young Earth Creationism not falsified by the fossil record—given the kind of immunizing strategies employed by its proponents—it
cannot
be falsified by the fossil record or indeed by anything else. It is, in effect, an unfalsifiable theory.

So far as the notion of falsification is concerned, a pivotal figure is the philosopher Karl Popper. Popper developed a philosophical theory called
falsificationism
, which describes how science progresses. Few philosophers now embrace falsificationism,
and I certainly won't be relying on that theory here. Nevertheless, Popper did make a number of points relevant to our discussion.

We have already seen how scientific theories can be falsified—we can derive from them observational predictions that can then be checked. If the prediction turns out to be false, then the theory is falsified. However, Popper notes that various strategies can be employed by defenders of a theory to deal with an apparent falsification—to
protect
or
immunize
it against falsification. It is on such immunizing strategies that I am going to focus here. Let's begin with some examples.

Blame an Auxiliary Hypothesis

Here's one obvious way of protecting a theory from falsification. We have already seen that, in order to derive a prediction from a theory, it's often necessary to employ
auxiliary hypothesis.
We saw that Newton's theory of universal gravitation predicts a smooth, elliptical orbit for Uranus only if no other planet is exerting a gravitational effect on it. When Uranus turned out not to have a smooth, elliptical orbit—it wobbles slightly in and out of its predicted orbit—defenders of Newton's theory insisted that, rather than falsifying Newton's theory, this observation revealed only that there was another as-yet-unknown object in the vicinity of Uranus tugging it out of its elliptical orbit. In other words, the falsification was
deflected away from the core theory and onto an auxiliary hypothesis.
Scientists calculated where this mystery object would have to be in order to exert such a pull, looked for it, and discovered a new planet: Neptune.

Here's another example. When Galileo constructed his telescope, looked at the moon, and observed mountains and valleys, it seemed that Aristotle's theory that every heavenly body is perfectly spherical had been falsified. Instead of accepting this, some defenders of Aristotle's view suggested that there must be an invisible substance covering the surface of the moon, filling up its valleys right to the tops of the mountains, so that the moon is,
after all, perfectly spherical. The falsification was in this case deflected away from Aristotle's theory and on to the auxiliary hypothesis that any material making up the surface of the moon must be visible.

Other strategies for defending a theory include exploiting vagueness and ambiguity in the theory or the predictions derived from it—to reinterpret them so that what is observed turns out to “fit” after all. This is, as already noted, a favorite trick of psychics and soothsayers.

Ad Hoc Maneuvers

Popper realized that even mainstream scientists can and do employ such strategies in order to defend their theories. He did not think this was
always
a bad thing. In particular, Popper thought that defending Newton's theory of universal gravitation by postulating a mystery planet was entirely acceptable, because it led to
new tests
—scientists could actually look to see if there was planet in the place predicted.

What Popper considered
particularly
suspect were attempts to defend a theory by means of modifications that introduced
no new tests.
So, for example, the postulation of an invisible substance on the surface of moon in order to salvage the Aristotelian theory that all heavenly bodies are perfectly spherical led to no new tests—there was nothing scientists could do at the time to check whether any such substance was there. Popper calls such untestable hypotheses introduced to immunize a theory against falsification “ad hoc.”

Popper noted that the more such strategies are employed to protect a theory from falsification, the less falsifiable it becomes, until eventually we end up with a theory that is not falsifiable at all. In Popper's view, an unfalsifiable theory is not scientific. Theories that claim to be scientific but fail to meet the test of falsifiability are mere pseudoscience.

TWO KINDS OF IMMUNITY TO FALSIFICATION

My suggestion is that Young Earth Creationism, as promoted and defended by today's adherents, is also an unfalsifiable theory. But, before we look again at Young Earth Creationism, it's worth taking a short detour to look at two quite different ways in which theories can achieve unfalsifiability. We'll see, interestingly, that there are at least two versions of Young Earth Creationism, and they achieve unfalsifiability in a different way.

Popper himself distinguishes two ways in which a theory might be rendered unfalsifiable. Let's focus for a moment on Popper's own examples. He considered both Marx's theory of history and the psychoanalytic theories of Freud and Adler unfalsifiable, but for different reasons.

The problem with Freud's and Adler's psychoanalytic theories, thought Popper, is that, whatever human behavior is observed, it can always be interpreted to “fit” either theory. Popper, who knew Adler, remarks:

As for Adler, I was much impressed by a personal experience. Once, in 1919, I reported to him a case which to me did not seem particularly Adlerian, but which he found no difficulty in analyzing in terms of his theory of inferiority feelings, although he had not even seen the child.

Popper believed the same was true of Freud's theories. They both appeared to fit the evidence and to thus be supported by the evidence, no matter what evidence might show up. Popper illustrated by considering two hypothetical situations—one in which a man pushes a child into water with the intention of drowning the child, and one in which a man sacrifices himself to save a child. Popper claims each of these two events can be explained with equal ease in Freudian and Adlerian terms:

According to Freud the first man suffered from repression (say, of some component of his Oedipus complex), while the second man had achieved sublimation. According to Adler the first man suffered from feelings of inferiority (producing perhaps the need to prove to himself that he dared to commit some crime), and so did the second man (whose need was to prove to himself that he dared to rescue the child).

Popper found he couldn't think of any human behavior that
wouldn't
fit either theory:

It was precisely this fact—that they always fitted, that they were always confirmed—which in the eyes of their admirers constituted the strongest argument in favor of these theories. It began to dawn on me that this apparent strength was in fact their weakness.
¹²

So Popper thought these two psychoanalytic theories were unfalsifiable, and for much the same reason. Popper also thought that Marx's theory of history was unfalsifiable, but for a different reason. According to Popper, unlike Freud's and Adler's theories, Marx's theory
started out
as a falsifiable theory. In fact, it made some rather risky predictions about how history would unfold. For example, it predicted the character of a coming social revolution (for example, it predicted the revolution would happen in an industrially advanced society such as Britain). However, this prediction turned out to be largely incorrect (there was a revolution, but it did not take place in the way Marx predicted—it actually happened in industrially backward Russia). Marx's theory was therefore falsified. Rather than accept this, Marx's followers employed an immunizing strategy, reinterpreting theory and evidence so that the theory continued to fit the evidence after all:

Instead of accepting the refutations the followers of Marx reinterpreted both the theory and the evidence in order to make them agree. In this way they rescued the theory from refutation; but they did so at the price of adopting a device which made it irrefutable.
¹³

Dave's Immunizing Strategy

Let's now return to Dave's theory that dogs are spies from the planet Venus. Mary and Pete tried to falsify Dave's theory, but each time they tried, Pete came up with yet another explanation for why his theory is, after all, consistent with the evidence. While some of Dave's moves are rather ad hoc in nature, others are not. His suggestion that the dogs' transmitters are located in their brains does in fact lead to a
new test
—we could look inside dogs' brains to check whether there are any transmitters. However, when no transmitters show up, Dave just makes another adjustment—he says the transmitters must be made of organic material indistinguishable from brain stuff. So while not every immunizing move Dave makes is ad hoc, his
overall strategy
renders his theory unfalsifiable. So, yes, today's Young Earth Creationists can say, “Our theory has not been falsified!” But that's only because, given their immunizing strategies, it
cannot
be.”

Clearly, Dave's theory suffers from the same problem that Popper found with Marxism. Dave's theory
starts off
as potentially falsifiable. However, once it
is
falsified, Dave develops an immunizing strategy that makes it unfalsifiable. Every time his theory runs into trouble with the evidence, Dave just makes another modification to deal with it: to make it
fit
the evidence after all.

As should now be clear, the version of Young Earth Creationism outlined above is also unfalsifiable, and for much the same reason. The theory that the earth was created just as described in Genesis
starts out
as a falsifiable theory. Indeed, it is straightforwardly falsified by a mountain of evidence. In response to the evidence, proponents of Young Earth Creationism, like Dave, then devise ever more ingenious moves to account for it. Once they have embarked on this strategy, their theory
becomes
unfalsifiable. It's
the strategy developed to defend the core theory, rather than anything about the theory itself, that makes it unfalsifiable.
So, yes, today's Young Earth Creationists can say, “Our theory has not been falsified!” But that's only because, given their immunizing strategies, it
cannot
be.

So, yes, perhaps Young Earth Creationists can correctly say “Our theory has not been falsified!” But if so, that is only because, given their immunizing strategy, it
cannot
now be falsified.

Gosse's Omphalos Hypothesis

There is an interesting contrast to be drawn here with a rather different version of Young Earth Creationism developed by Philip Henry Gosse. In 1857, Gosse published a book titled
Omphalos: An Attempt to Untie the Geological Knot.
Gosse tried to explain how the discoveries then being made in geology—such as the fossil record—that were beginning to seriously challenge the view that the earth was just a few thousand years old, were in fact entirely compatible with Young Earth Creationism
Omphalos
means “navel,” or “belly button.” Some Christians wondered whether Adam had one. One the one hand, it seems he wouldn't, because he had no mother to whom he was attached by an umbilical cord. On the other hand, it would be seem odd if Adam didn't have one, as it's an otherwise universal feature of human beings.