Jul 19 2012
Science makes predictions. That is inherent to the scientific process. It’s what makes hypotheses testable – they make predictions about what will be observed in nature, about the outcome of experiments, and about future trends and events. Scientific theories are really models that allow us to predict the behavior of the world, and they are judged on their utility for making such predictions, rather than whether or not they are objectively “correct” (because we can’t know that).
This was a simple point I was trying to make, with respect to evolutionary theory, in a recent post on feathered dinosaurs. Egnor, who fancies himself an evolutionary gadfly, has tried to counter my arguments but only manages to create a confusing mess. In my original post I made the point:
After Darwin published his theory of evolution one of the early challenges to the idea of evolution, which includes the claim that all life on earth is related through common ancestors, was that there were significant gaps between major groups of living creatures. Birds, for example, seem to be their own group without a close connection to any other group. They are, of course, related to vertebrates. But if evolution were true then there must be fossil evidence connecting birds to another group, such as reptiles.
Evolutionary theory predicted that gaps in the “tree of life” (the phylogenetic tree of evolutionary relationships) would be filled in by fossil discoveries. Birds had to evolve from something, so we will likely find fossils filling in the morphological space between birds and another related group, which turned out to be theropod dinosaurs. I go on to describe how this is exactly what has happened, and in fact we continue to find more and more evidence for feathered dinosaurs and dinosaur-bird intermediates. These discoveries confirm a prediction made by evolutionary theory.
Michael Egnor apparently does not understand that, or he wishes to cast doubt on this obvious conclusion. His post is so confused it is hard to pull an actual argument from it, but I will try. He writes:
But “evolution”– Novella means Darwinism– predicted none of this. I challenge Novella to cite references from evolutionary biologists during the past 150 years predicting that birds rather than reptiles would be found to be related to dinosaurs based on Darwinian principle of heritable variation and natural selection and common descent.
While T. H. Huxley was an early proponent of the dinosaur-to-bird theory, he based his view on morphological similarities and paleontological evidence, not on any insight gained from ‘random variation and natural selection’. And his view was rejected– in favor of the dinosaur-reptile theory– by the Darwinist-monopolized evolutionary community for 100 years.
That’s hardly a successful “prediction made by evolution”.
First, Egnor’s statements are hopelessly confusing – what does he mean “birds rather than reptiles” would be related to dinosaurs? Dinosaurs are not related to reptiles, they are reptiles. Dinosaurs are a superorder in the class Reptilia. The question at the time was whether birds evolved from dinosaurs or some other reptile. T.H. Huxley was an early proponent of the bird-dinosaur hypothesis, and he was joined by a few others, such as dinosaur paleontologist Franz Nopcsa. I’m not sure why Egnor thinks these evolutionary scientists don’t count.
Egnor further demonstrates his poor reading comprehension by completely missing the point I was making. As is very clear in the quote above, I never said that evolutionary theory predicted that birds evolved from dinosaurs. Never. I said that evolutionary theory predicted that something would fill the gap between birds and a related group “such as reptiles.” If evolution were not true, this would not have to be the case. Birds could exist as their own “kind” with no connection to the rest of life on earth. Evolution requires a connection – and now we have a robust one with reptiles, specifically theropod dinosaurs.
It is true I referred to “evolutionary” theory without specifying what aspect of the theory I was referring to – because I thought it was blazingly obvious, but apparently not obvious enough for Egnor. Evolutionary theory includes several components. The first, and the most overarching, claim is that all life on earth is related through common descent. That is obviously the aspect of evolutionary theory I was referring to when I said that it predicts the birds must be connected to another group.
A second and distinct aspect of evolutionary theory relates to the mechanism(s) by which evolution occurs. The current consensus is a modern version of Darwin’s theory of variation and natural selection. This aspect of evolution is independent from common descent, and has nothing to do with the point I was making. A third component of evolutionary theory is a phylogenetic tree or cladogram of which species evolved from which other species. This also is independent from the other two aspects of the theory. Common descent dictates only that there will be a connection – not what those specific connections will be. Morphological, genetic, developmental, and paleontological evidence is brought to bear to flesh out the evolutionary tree of life, and this is an ever-changing puzzle as new bits of information come it.
Now – do you see what Egnor did? He states: “But “evolution”– Novella means Darwinism– predicted none of this.” Egnor arbitrarily decided that by evolutionary theory I specifically meant Darwin’s theory of variation and natural selection, when it should be obvious that I was talking about common descent. He constructed a ridiculous straw man and then proceeded to dismantle his own creation (in a confused and factually challenged manner).
From reading Egnor’s post it seems that he has no problem with the notions of common descent, or that birds are related to dinosaurs. His boogeyman is the mechanism of evolution – natural selection. He prefers to believe that the mechanism is magic (meaning his personal supernatural beliefs) rather than any naturalistic process. So he sees his boogeyman everywhere, and will rant against it no matter the actual subject of the post he is attacking. The result is incoherent.
In a separate post Egnor claims that “survival of the fittest” is a tautology. This is an old creationist canard, long deconstructed, which never seems to bother creationists. He writes:
The theory about the causes of changes in populations over time (Darwin’s theory) asserts, when you strip away the pretentious junk-science and thinly disguised ideology, that life is explained by survival of fitter individuals, whose fitness is defined as their survival.
Wrong. Fitness is defined by a host of characteristics (strength, fecundity, acuteness of senses, attractiveness to the opposite sex, a functional immune system, etc.) that allows individuals to survive and reproduce.
Once again Egnor demonstrates that creationists in general, and he in particular, do not understand evolutionary theory or the arguments in its favor. He appears to work backward from his desired result – to rant against variation and natural selection as a major mechanism of evolutionary change over time. My original article had absolutely nothing to do with the mechanism of evolution, but Egnor managed to insert that claim just so he could have something to rant about.
Meanwhile, common descent is a solid prediction made by evolutionary theory (including Darwin himself) and the paleontological evidence for the evolution of birds from dinosaurs remains a shining example of the vindication of common descent.
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