Over at UD, GilDodgen has a long quote from Michael Behe claiming that ID is easily falsified while evolution cannot be. The quote is from the DVD Case for a Creator (this should of course really be “Case for an unnamed, undefined and possibly non-divine intelligent designer”, but apparently they were feeling a bit lazy that day). I want to look at both parts of Behe’s claim. Here’s the first:
The National Academy of Sciences has objected that intelligent design is not falsifiable, and I think that’s just the opposite of the truth. Intelligent design is very open to falsification. I claim, for example, that the bacterial flagellum could not be produced by natural selection; it needed to be deliberately intelligently designed. Well, all a scientist has to do to prove me wrong is to take a bacterium without a flagellum, or knock out the genes for the flagellum in a bacterium, go into his lab and grow that bug for a long time and see if it produces anything resembling a flagellum. If that happened, intelligent design, as I understand it, would be knocked out of the water. I certainly don’t expect it to happen, but it’s easily falsified by a series of such experiments.
This is the same argument that he and Scott Minnich made in their testimony in the Dover trial; it didn’t work then and it won’t work now, for two primary reasons: first, because such an experiment could never approximate the actual conditions in which the flagellum evolved, and second, because even if a flagellum did evolve, the ID advocates would not actually accept it as a falsification of irreducible complexity. Let’s take the first argument first.
Frankly, Behe is being disingenuous here when he claims that scientists could just remove the flagellum from a bacterium and see if one evolves again. He knows this because he and his colleagues love to do these amazing probability calculations for how unlikely it would be for the flagellum to evolve step by step, and some of the variables included in those calculations are variables that simply cannot be replicated in a lab. Bacteria have been evolving for around 3.8 billion years on the Earth, and they exist on earth in numbers that can barely be expressed even mathematically.
There simply is no way to replicate the number of sequential trials (i.e. the total population of bacteria or the amount of genetic variation within that population) or the amount of time involved. A researcher might work with a population of a few billion bacteria for his entire professional career of 50 years or so and he would not have replicated the actual population or time involved in nature to even one billionth of the actual numbers. And that’s not even counting the fact that we can’t possibly replicate all of the relevant selective pressures that various subpopulations might have been under that allowed the mutations that developed the flagellum to become fixed in the first place.
Behe knows all of this, and we know he knows all of this, because when he’s done his own research even on a much less complex biochemical system, a single protein binding site, he had to use a computer simulation to do it. When he and Snoke did the work for their 2004 Protein Science paper, they knew that even for a relatively simple experiment involving only a few point mutations in a single enzyme within a bacteria, they could not possibly replicate real world conditions in the lab.
They knew that the only way they could even come close was by using computerized artificial life programs to speed up the whole process. And even then, they rigged the conditions to make it as unlikely as possible and as unlike the real world as possible, but the computer simulation still showed that a binding site that Behe himself characterized as irreducibly complex could evolve in 20,000 years. Yet here he is demanding that scientists do an actual experiment with actual bacteria, the numbers of which could not possibly be contained in a lab, on the evolution of a much more complex biochemical system that would almost certainly take longer to evolve than the whole of recorded human history.
Reasonable? Of course not. This is like arguing that a solar system could not have come together on its own without divine intervention, and that you can easily falsify that claim merely by creating a solar system in your laboratory – assuming, of course, that you had a laboratory that could hold and contain a 50 million mile thick fusion nuclear reactor at temperatures that would melt the earth. This is precisely what Judge Jones was referring to in the Dover ruling when he said that the IDers intentionally demand an absurd level of proof that they know cannot be met.
But here’s the punchline: even if a scientist did manage to do such an experiment and a flagellum did re-evolve in the lab, would they really accept this as proof that ID was false? Not on your life. They would immediately make two arguments:
1. “All this shows is that it can only happen in the lab, where the scientist intervenes as an intelligent designer to ensure the result. This only proves that intelligent intervention is required to bring about a flagellum”; and,
2. “If the information for the evolution of the flagellum was front loaded into the bacterial DNA by the Intelligent Designer, then of course a flagellum would re-evolve if you removed it; it was designed that way.”
How do we know that they would make those arguments? Because they’ve already made them. Here is Behe himself on front-loading:
Suppose that nearly four billion years ago the designer made the first cell, already containing all of the irreducibly complex biochemical systems discussed here and many others. (One can postulate that the designs for systems that were to be used later, such as blood clotting, were present but not “turned on.” Om [resent-day organisms plenty of genes are turned off for a while, sometimes for generations, to be turned on at a later time.)
Mind you, as a biochemist Behe knows perfectly well what happens to unexpressed DNA; because it’s not expressed in the phenotype it can’t be selected for, so mutations accumulate massively over the generations until the genes are completely useless. Thus, along with this front loading he also has to posit that the undefined designer (wink, wink) also intervened constantly to prevent that from happening. Given that level of constant intervention in the natural order, how could any experiment like this possibly falsify such a designer’s actions? It simply can’t happen, not even hypothetically.
Now let’s turn that around and ask, How do we falsify the contention that natural selection produced the bacterial flagellum? If that same scientist went into the lab and knocked out the bacterial flagellum genes, grew the bacterium for a long time, and nothing much happened, well, he’d say maybe we didn’t start with the right bacterium, maybe we didn’t wait long enough, maybe we need a bigger population, and it would be very much more difficult to falsify the Darwinian hypothesis.
But this is a profoundly silly argument, based upon the same ridiculous premise as his argument above. If it isn’t possible to replicate the population size, the amount and type of genetic variation, the amount of time involved, or the selection pressures specific to the environment at the time – and it’s not – then of course you can’t falsify evolution in this manner. But that does not, of course, mean that evolution can’t be falsified or tested at all, nor does it mean that we can’t use lab research to confirm smaller parts of that testing.
Because the evolution of these biochemical systems happened primarily in the distant past and took place over such long periods of time, we will never have a videotape-level display of how exactly they took place, which is the only thing that will satisfy the IDers (as Behe made very clear in his testimony in Kitzmiller). But we can use this kind of research to help us understand how they developed in a number of different ways. And Behe accepts all of those ways, and accepts that they can in fact demonstrate plausible evolutionary pathways for the development of complex biochemical systems.
He’s perfectly fine, for example, with the evolution of the antifreeze proteins in arctic fish having developed via mutation and selection, despite the fact that we don’t have the kind of undeniable mutation-by-mutation videotape of how it happened. But what we do have is precisely the kind of lab research that Behe rejects when it comes to the flagellum, research that compares specific genes in closely related species to see, for example, how a gene in one species is duplicated in another species, which provides the raw material necessary for adaptation. We have the research showing that the antifreeze proteins are virtually identical to the pancreatic protein trypsinogen, and much more. We can infer from this the likely pathway taken to evolve a particular trait. His arguments in regard to the flagellum are a textbook example of special pleading.