In Popper’s view (and I agree with him), while you can never prove a scientific theory, you should be able to demonstrate it to be incorrect. In other words, a scientific theory should be falsifiable. There should be the possibility that some discovery would end up demonstrating that the theory is false. If a scientific theory can accommodate any data, it is not a scientific theory. This, of course, makes sense. If a theory is so plastic that it can be molded to fit any data, it is definitely not scientific.
Dr. Hunter says that evolution is not falsifiable because it is a negative argument. As he puts in in the post mentioned above:
Evolution is, and always has been, motivated by failures of creationism and design. If god did not design or create this world, then it must have evolved. Somehow. Evolutionists perform research to try to figure out how evolution could have happened, but it must have happened—that much they know. That is a metaphysical position, not a scientific position, based on a negative argument. It is not falsifiable.
While I agree with the last sentence in that quote, I don’t agree with anything that comes before it.
I don’t think evolution is a negative argument. I don’t think it is simply the result of people thinking God didn’t create. Now don’t get me wrong. There are probably plenty of evolutionists who believe in evolution simply because they don’t want to believe that God created. That’s fine, but it’s not very scientific. It’s also not representative of the majority of evolutionists out there. I think evolutionists believe in evolution because they see evidence for it. Similarities between different organisms, for example, represent (in their minds) strong evidence for common ancestry.
Given that evolution isn’t a negative argument, is it falsifiable? I think that it initially was. Darwin made all sorts of predictions, but many of them have been falsified. In order to “save” evolution, however, evolutionists simply started adding caveats to “explain around” the falsifying data. As a result, we now have an evolutionary theory that is so plastic it can be molded around any kind of data. This makes it not falsifiable, and thus not scientific.
To give you an example of the flexibility of evolutionary theory, lets start with something Darwin said:
If it could be proved that any part of the structure of any one species had been formed for the exclusive good of another species, it would annihilate my theory, for such could not have been produced through natural selection.1
Of course, there is a common example of just such a situation. Indeed, I fight this common example every spring. It is the backyard dandelion. There are many species of dandelion, and most of them reproduce sexually. However, the common backyard dandelion does not. It’s only mode of reproduction is asexual.2
Do you see the problem with this? The common dandelion plant produces flowers, and those flowers produce nectar. Insects love to eat that nectar. Now if the common dandelion reproduced sexually, this would benefit the dandelion. The insects would get pollen on them, and when they went to the next flower, they would transfer that pollen to the next plant, and that would allow the two plants to sexually reproduce. However, the common backyard dandelion doesn’t sexually reproduce, the nectar it produces gives it no benefit. The nectar benefits the insects only. Thus, here is a plant that produces nectar, and that nectar benefits only other organisms. This, of course, is exactly what Darwin says would “annihilate” his theory.
Of course, evolutionists cannot let that happen, so they have to come up with some caveat to fix the situation. As a result, they say that the common dandelion did have a sexual mode of reproduction at one time, but it was eventually lost. Thus, the nectar production is a left-over remnant of a mode of sexual reproduction that once existed.
In the end, I have no problem with that argument. It seems very reasonable. However, please realize what it implies, because it will become important in a moment. The dandelion expends a lot of energy producing the nectar that gives it no benefit. Thus, to believe in this explanation, we must believe that natural selection allows an organism to be incredibly wasteful – it keeps around a vestige from a system it no longer has, regardless of the fact that it is expending a huge amount of energy to keep it.
Why is this a problem? Well, let’s look at another situation. Apes have an excellent sense of smell, but their eyesight leaves a bit to be desired. Humans have much better eyesight than apes, but they have a worse sense of smell. Because of the similarities between apes and humans, it is assumed that they both shared a common ancestor. In addition, it is expected that this ancestor was rather “ape-like.” Most evolutionists, then, assume that through the process of evolution, humans developed better eyesight, but their sense of smell actually got worse.3
Once again, there is a reasonable explanation for this as well. If the common ancestor of apes and humans lived mostly in the woods, the sense of smell would be more beneficial than the sense of sight. Over the course of evolution, however, if humans moved out of the forests and onto the plains, the sense of sight would be more important. Thus, natural selection would select for better sight, and since organisms can’t afford to be wasteful when it comes to resources, it would select against the apelike sense of smell. As a result, humans developed better eyesight, and they ended up with a worse sense of smell in order to conserve resources.
I have no problem with this argument, either. As I said before, it is reasonable. The only problem is that it is incompatible with the explanation regarding the dandelion. In the case of the dandelion, natural selection allows it to waste an enormous amount of energy producing nectar that it never uses. However, in the case of human evolution, natural selection could not even allow the sense of smell to be as keen as it once was, because human beings couldn’t afford to waste resources on a less-useful sense.
This, as I see it, is the reason evolution cannot be falsified. It simply has too many excuses built into it. With enough excuses, you can accommodate any amount of data. As I have mentioned previously, similarities among organisms are supposed to be evidence of common ancestry. However, there are many, many examples of similarities between species that evolution cannot accommodate as being linked by a common ancestor with such a trait. As a result, evolutionists call that “convergent evolution” – a case in which evolution “just happened” to come up with similar traits in two unrelated organisms. In other words, similarities between organisms are evidence of evolution when evolution can accommodate them, and they are simply the result of chance when evolution cannot accommodate them.
When a theory is so plastic that it can be molded to fit any data, it is no longer a scientific theory. That’s where evolution is today.
2. David Sadava, H. Craig Heller, David M. Hillis, May Berenbaum, Life: The Science of Biology, Macmillon, 2009, p. 810
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3. Kitcher, P., Abusing Science: The Case Against Creationism, MIT Press, 1982, pp. 73-74
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