Apr 16 2007
I’m loving it. We have a nice little war raging in the science blogosphere between those of us defending science and reason (in this particular case evolutionary theory) and apologists for intelligent design (specifically the Discovery Institute’s latest mouthpiece, neurosurgeon Dr. Michael Egnor). Recently I discussed the fact that training in neurosurgery does not necessarily prepare one to have a respectable opinion about evolution. I also took some jabs at ID proponents’ abuse of information theory. Well Dr. Egnor has fired back with an article about me on the Discovery Institute’s website.
First, I can’t help but be tickled that I am denigrated as a “Yale Darwinist” on the DI website. Let me quote the eminent politician and statesman James Danforth Quayle by saying, “I wear their scorn as a badge of honor.” So, thanks.
The rhetoric Dr. Egnor uses in his article is also very telling. He refers to me multiple times as a “Darwinist” – the term preferred by creationists and ID’ers to refer to those who accept the overwhelming consensus of scientific opinion that evolutionary theory is well established as a fact. Eugenie Scott astutely pointed out when we interviewed her for our podcast that they use the term Darwinist in a deliberately derogatory fashion – to imply that belief in evolution is an “ism”, an ideology. It demonstrates that Dr. Egnor is thoroughly versed in the propaganda of the Discovery Institute.
Dr. Egnor makes two basic points in the article. The first one is a repetition of his primary point about which he has been engaging with PZ Myers,Orac , Ed Brayton and other science bloggers – he asks for evidence that random mutation and natural selection can increase genetic information over time. He writes, “Actually, all I did was ask a question: how much biologically relevant information can Darwin’s mechanism of chance and necessity actually generate.”
Reading back it is clear that his question initially was to ask “how” evolution can increase information. This was answered by multiple people, with copious references to the literature showing, for example, how gene duplication and later mutation and cooptation can lead to the addition of meaningful genetic information. Here is an article on Talkorigins.org reviewing this question with many of the very references Dr. Egnor asks for. Now (without ever acknowledging that his initial question was answered) it seems he is asking for evidence of precisely how much new information evolutionary processes can generate over time.
Dr. Egnor is just nudging back the goalpost. A classic denial strategy is simply to ask for more evidence than is currently available. I will be the first to admit that we do not know everything about the history of life – and we never will. Evolution deniers like Egnor can always find something to ask for that is not currently known, or not precisely enough. And when it is, they will shift to something else. This is what Judge Jones concluded in the Dover trial – the challenges of ID proponents had been met by subsequent research, but they never acknowledged it. He wrote: “We find that such evidence demonstrates that the ID argument is dependent upon setting a scientifically unreasonable burden of proof for the theory of evolution.” They just keep moving the goalpost – so there is no reason to suspect that their questions are sincere scientific inquiries. They have demonstrated them to be ideological denialist posturing.
The evidence in the published literature is overwhelming that modern genes have evolved from older genes, that many genes are related to each other, that genetic information has increased over evolutionary time. Further, there is copious and undeniable evidence that all known life on earth is related, and in an evolutionary pattern that follows morphological, biochemical, and fossil evidence. For example, the specific pattern of three nucleotides that code for amino acids, and the specific sequence of amino acids that make up the same proteins in different species are very similar but not identical. There is no functional reason for them to be similar, and if they were simply created there is no reason for them to vary. And they don’t vary at random – they vary in a perfect evolutionary pattern. The more closely related two species are evolutionarily, the more similar their nucleotide and amino acid sequences. Heredity is the only scientific explanation for this pattern.
Mark C. Chu-Carroll over at Good Math, Bad Math, also wrote a reply to Egnor’s response to my post. In the article he notes that Dr. Egnor’s challenges for published studies showing that evolutionary processes can account for a sufficient increase in information have been met. In response Dr. Egnor just changes his definition of “information” to wiggle out of the evidence. It is also important to note that given it is well established that the proven genetic mechanisms outlined above can increase specified genetic information over time, and current genetic information seems to have come about from these and similar mechanisms, we can reasonably infer that evolutionary processes can and have produced the current level of genetic diversity. Given this it is appropriate to place the burden of proof back on Dr. Egnor. So I challenge him to cite a valid reference or combination of references that indicate evolutionary forces could not have produced the requisite genetic information in the time available.
Dr. Egnor’s second main point at least is a new one – as far as I am aware. It also ranks among the most ludicrous arguments against evolution I have ever heard. Dr. Egnor writes:
“According to Dr. Novella’s reasoning, brain tumors ought to be generating quite a bit of “meaningful and even useful new information.” Better neuroanatomy and better neurophysiology ought to be popping up “easily.” Better frontal lobes and cognition, from cancer. Better temporal lobes and memory, from cancer. Better cerebellums and coordination, from cancer. If random mutations and natural selection—Dr. Novella’s “two stroke engine”—is the source of all functional integrated biological complexity, brain tumors ought to help our brains evolve in some way.”
He is trying to say that mutations causing the appearance of cancer cells within an organism is a good analog of evolution – that the evolutionary processes of mutation and selection should operate on cancers to evolve them into better organs. You read that correctly. And yet he takes offense at my “disdain” for “Darwin doubting.” I love it when they make my job so easy. I almost feel guilty. Well…not really.
There are two major conceptual flaws in Dr. Egnor’s reasoning. The first is that brain cancer is capable of creating better brain tissue. Rather, cancer represents a somatic mutation – a mutation within a non-reproductive cell within an individual organism. It cannot affect the development and therefore organization and structure of the brain. To suggest that it should be able to do this (if evolution were correct) is absurd – coming from a neurosurgeon it is shocking and disturbing.
To be clear on this point, mutations that result in the change of anatomy, physiology, or biochemistry of an organism (not an individual cell) must be present at conception or early in development, and must occur in a gene that controls such things. Once the brain is fully developed there is no conceivable mutation that could alter its structure.
The second major misconception is that evolutionary forces should push cancer cells to form better functioning anatomy and physiology – a better brain (and the fact that it never does proves that evolutionary forces don’t work). Cancer is actually a good example of evolutionary forces in the proper context of the competition for survival of cells within an organism. Cells can compete with each other for survival, just like individuals fight for survival within a population. Individuals are not working for the betterment of the population – just their own survival. Likewise, mutations that result in cancer allow the cancer cells to out-compete other cells. They grow and reproduce without limit, using up resources and crowding out and even destroying other cells. But those pressures cannot work toward the betterment of the entire organism. Evolutionary pressures do not operate at higher hierarchical levels – only for the survival of the individual- in this case individual cells.
Therefore Dr. Egnor conveniently demonstrates a significant lack of understanding of evolution in his argument. Darwinian selection only creates pressure for immediate survival advantage of the individual – it cannot plan strategically for the future, nor can it look at the “big picture.” Therefore it is common for species to evolve themselves into a corner – to undergo adaptations that give them a survival advantage in the short run but doom them to extinction in the long run. The total dependence of koalas on eucalyptus trees, or the pretty but burdensome tail display of the peacock are good examples.
Likewise cancer cells survive and spread because their mutation gives them an immediate survival advantage – even though it may doom the organism to an early death.
To be crystal clear on this point – somatic mutations and selective pressures can only affect the differential survival of cells within an organism – any effect on the organism as a whole is incidental. There would be no selective pressures for cancer cells to form better brain structures.
Further, mutations that cause cancer are a specific kind of mutation – one that changes the lifecycle of a cell so that it become immortal (it can divide an unlimited number of times) or does not undergo apoptosis (programmed cell death) when it is supposed to. So one or more of the normal mechanisms that keep cells from growing out of control stops working because of a mutation. The notion that a brain tumor (a mass of cells growing without restriction) should form (according to evolutionary theory) functional organized structures is a bit of utter nonsense.
To summarize, there is no plausible mechanism by which a somatic mutation, and specifically cancer, could form useful structures in a mature individual, and, even if there were, selective pressures operating at the level of cells would not favor the function or survival of the organism as a whole.
Perhaps the term “rube” was being far too kind.
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