Friday, November 17, 2006

Why I'm Not a Darwinist

Charles Darwin was the greatest scientist who ever lived. This may seem like an exaggeration to many people who take evolution for granted, and it appears downright ludicrous to those who reject evolution for religious reasons. But really, who are the other candidates? Newton is the only one who comes close and his contributions were nowhere near as significant and far-reaching as those of Darwin. Biology is much harder than physics.

Darwin discovered natural selection and he promoted and sold the idea of common descent. He founded evolutionary biology. Today evolutionary biology is one of the largest and most exciting fields in all of science.

We all know about evolutionary biology, but what is "Darwinism?" Ernst Mayr has an entire chapter devoted to the question ("What is Darwinism") in his book One Long Argument (Mayr, 1991). At the end of that chapter he says, ...
After 1859, that is, during the first Darwinian revolution, Darwinism for almost everybody meant explaining the living world by natural processes. As we will see, during and after the evolutionary synthesis the term "Darwinism" unanimously meant adaptive change under the influence of natural selection, and variational change instead of transformational evolution. These are the only two truly meaningful concepts of Darwinism, the one ruling in the nineteenth century ... and the other ruling in the twentieth century (a consensus having been reached during the evolutionary synthesis). Any other use of the term Darwinism by a modern author is bound to be misleading.
I agree with Mayr on this point. Darwinism refers to evolution by natural selection. But a "Darwinist" is not just someone who accepts the fact of natural selection, it's more than that. It's someone who prefers this explanation to all other possible mechanisms of evolution. This is the point made by Stephen Jay Gould in his famous 1982 Science paper, "Darwinism and the Expansion of Evolutionary Theory." (The Gould quote about semantics in the left sidebar is from that paper.) Gould defines modern Darwinism as ...
If we agree, as our century generally has, that "Darwinism" should be restricted to the world view encompassed by the theory of natural selection itself, the problem of definition is still not easily resolved. Darwinism must be more than the bare bones of the mechanics: the principles of superfecundity and inherited variation, and the deduction of natural selction thereform. It must, fundamentally, make a claim for wide scope and dominat frequency; natural selection must represent the primary directing force of evolutionary change.
Richard Dawkins is a Darwinist and Daniel Dennett is a Darwinist. I am not a Darwinist. I prefer a modern pluralist view of evolution as I explain in Evolution by Accident.

I am not a Darwinist, just as most of my colleagues in the Department of Physics are not Newtonists, and most of my friends who study genetics are not Mendelists. All three of these terms refer to the ideas of famous men (Charles Darwin, Isaac Newton, Gregor Mendel) who made enormous contributions to science. But in all three cases, the modern sciences have advanced well beyond anything envisaged by their founders.

Call me an evolutionary biologist.

21 comments:

  1. Umm, Darwin did not discover natural selection. Natural selection was written about before Darwin published his ideas about it- See Ed Blythe.

    Also the sad thing is after all these years we still don't know what matutaions caused what changes and we don't even know if any mutation/ selection process can afford the range of change required if today's diversity of living organisms owed its collective common ancestry to some unknown population(s) of single-celled organisms.

    Common Descent relies on similarities where it needs to explain the differences- something no one has done.

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  2. How does evolution by accident explain convergent evolution (evolving the eye several times independently, for example)?

    Chance is of course crucial to evolution, but it becomes less of a directing force when it occurs in smaller increments for (even weak) selection to act on. Asteroids would be a different matter.

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  3. jeffw asks,
    How does evolution by accident explain convergent evolution(evolving the eye several times independently, for example)?

    That's due to natural selection. Darwinists, also called adaptationists, attribute everything to natural selection. Pluralists like me don't deny natural selection but we know that there are lots of other things going on.

    The debate between supporters of Gould and supporters of Dawkins has been going on for 30 years. If you support Dawkins you are happy to be called a Darwinist. If you support Gould, as I do, then that label is odious and incorrect.

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  4. "Darwinists, also called adaptationists, attribute everything to natural selection. Pluralists like me don't deny natural selection but we know that there are lots of other things going on.

    The debate between supporters of Gould and supporters of Dawkins has been going on for 30 years. If you support Dawkins you are happy to be called a Darwinist."

    Hang on a minute! To be fair to Dawkins, he has never claimed that ALL evolutionary change is due to natural selection. Here for example is Dawkins from 'The ancestor's tale':

    "Contrary to my rather ludicrous reputation as an 'ultra-Darwinist'.....I do not think that the majority of evolutionary change at the molecular level is favoured by natural selection. On the contrary, I have always had a lot of time for the so-called neutral theory associated with the great Japanese geneticist Motoo Kimura..".

    Dawkins' point is that we need natural selection to explain adaptive change. Last time I looked in my text-books, that was a pretty orthodox view.

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  5. I have never heard anyone attribute everything (pertaining to evolution) solely to natural selection. Not Dawkins, not Darwin and not one of my zoology profs.

    I think Larry made that up. Just like he made up that Darwin discovered natural selection- which is demonstratably false.

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  6. tony jackson says,

    Dawkins' point is that we need natural selection to explain adaptive change. Last time I looked in my text-books, that was a pretty orthodox view.

    Not only is it the orthodox view, it's the only view. There's no other way to explain adaptation.

    The difference between Dawkins and the pluralists is that Richard Dawkins inclines to the view that the only significant evolution is adaptation. While admitting that random genetic drift predominates at the molecular level, he doesn't think it counts as real evolution.

    Furthermore, he pretty much assumes that all phenotypic change is due to natural selection. This is not correct. Adaptationists attribute much more to adaptation (via just-so stories) than pluralists do.

    People can quibble about semantics until the cows come home but that doesn't mean the debate between adaptationists and pluralists is going to go away. Look at the Gould quote in the sidebar—there's more going on here than mere semantics.

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  7. Well Dawkins can defend himself, but I'd be surprised if he believes that ALL phenotypic change is due purely to natural selection. Where in any of his writings does he say that?

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  8. Charles Darwin was the greatest scientist who ever lived. This may seem like an exaggeration to many people who take evolution for granted, and it appears downright ludicrous to those who reject evolution for religious reasons. But really, who are the other candidates? Newton is the only one who comes close and his contributions were nowhere near as significant and far-reaching as those of Darwin. Biology is much harder than physics.

    Bullshit. Biology is fluff compared to the mathematical sciences.

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  9. tony jackson asks,

    Well Dawkins can defend himself, but I'd be surprised if he believes that ALL phenotypic change is due purely to natural selection. Where in any of his writings does he say that?

    Here, from The Extended Phenotype p. 32 ....

    The adaptationist controversy is quite different. It is concerned with whether, given that we are dealing with a phenotypic effect big enough to see and ask questions about, we should assume that it is the product of natural selection. The biochemist's 'neutral mutations' are more than neutral. As far as those of us who look at gross morphology, physiology and behaviour are concerned, they are not mutations at all.... If a whole-organism biologist sees a genetically determined difference among phemotypes, he already knows he cannot be dealing with neutrality in the sense of the modern controversy among biochemical geneticists.

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  10. aristotle, galileo, and einstein (and newton) were all better, i think, than darwin. biology might be harder than physics now, thanks to the hard work of physicists in the past, but it's no small feat to get us to where we are now. that sentence is just begging to be disagreed with. and it's pretty hard to explain quantum theory or relativity. i can't think of anything in biology that is that hard to wrap your mind around, even after learning it.

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  11. "aristotle, galileo, and einstein (and newton) were all better, I think, than darwin."

    First of all, you have no reason to be taken seriously if you do not capitalize. Second of all, Galileo or Newton were perhaps better. Einstein maybe not. But Aristotle was definitely not better than Darwin (or Galileo, Einstein, Newton, etc.). He may have been extremely clever, but he was a terrible scientist! Science is based on observation. Aristotle was all about a priori reasoning. If we still took Aristotle's attempt at science seriously, then we would deny gravity, believing that objects fall because of an "internal desire" to do so.

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  12. To Robert O'Brien - at least as far as evolution is concerned, biology is very much a mathematical science. The amount of rigorous mathematical work that's been done in population genetics and on genetic drift is astounding, and it's by no means light, airy work. I suggest you look up Kimura and Fisher and the like before you insult what you may not be familiar with.

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  13. I haven't read "evolution by accident" yet, but I'm suspicious that I would agree. Never the less, I think I'd prefer to stick with the label "darwinist" for the sake of simplification, since I do think that NS plays a huge role, and I bet my pinky finger nail that you do too - for instance, hummingbirds didn't "accidentally" adapted to lick nectar and then just realized that they could live much better doind that than whatever they've been doing on another niche that eventually acidentally made them quite "perfect" nectar-feeding birds.

    I just prefer to say that I'm not a panadaptationist and that developmental constraints, drift, population sizes and other things than simplistic NS play a huge role on evolution.

    Doing this way, I don't feed creationists or not well informed laymen with notions that NS is "just a theory" and could be another totally drastically different, "energy" like explanation for life (perhaps even common ancestry, which may be misunderstood as "just a theory" as well) and adaptation.

    When proeminent biologists (I'm not even a biologist) do that, it gives me some creeps... I just can anticipate new quote mining from creationists and other being fooled... then we have all the work to explain it... again...

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  14. What you guys need to understand is that Dawkins has a tendency to disconnect the molecular genetic from the morphological phenotype.

    For those of us with experience in both fields, it is abundantly clear that both are highly affected by evolution of the non-seletional kind.

    Try carrying out phylogenetic analysis based on leg bones if you don't believe me :D

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  15. Einstein home-boy, eintstein!!

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  16. Once someone asked me (I work with electronics) what Thomas Edison would think if he could "come" to the world today. I answered: first he would obviously be amazed at all he would see, but when he knew of the date we are he would certainly ask: is that all you've done up to now?
    A scientist is a scientist and the rest is nothing. A scientist doesn't follow the scientific method, he doesn't need it. The scientific method is only a ridiculous gift uselessly given to mankind to try to see if it could understand anything. Of course, it didn't work.
    And as a last say:
    The only science there is is Physics.

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    1. "Once someone asked me (I work with electronics) what Thomas Edison would think if he could "come" to the world today. I answered: first he would obviously be amazed at all he would see, but when he knew of the date we are he would certainly ask: is that all you've done up to now?"

      No, Thomas Edison was an zealous businessman before anything else. His first thoughts would be how to corner any chosen business by buying or stealing other people's inventions. He was the Bill Gates of his day with a near-monopoly of the fledging movie industry. (The movie industry was oddly built on studios pirating Edison's patents, which moved to the opposite coast to avoid paying Edison's exorbitant license fees.)

      There's also Edison's war with Westinghouse over whether the country should use AC or DC electrical mains which is over-the-top FUD at its most absurd with Edison creating the electric chair just to give AC bad press.

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  17. Moran posted:
    "Adaptationists attribute much more to adaptation (via just-so stories) than pluralists do."

    Do pluralists have their own just-so stories? Or is it only adaptationists that have just-so stories?

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  18. "Biology is much harder that physics". Well, two things. First, this is subjective. Secondly, this is asserted with no evidence whatsoever. I think a physicist would be unlikely to make a claim of this sort. Which perhaps says something about the rigor of the two fields. It seems to me biology is messier and computationally more complex, but that does not necessarily mean "harder"

    I would place Newton first, Darwin second.

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  19. "But really, who are the other candidates? "

    Wallace?

    Darwin and Wallace's contribution was to suggest that natural selection was a creative force that could cause new species to evolve. Until then natural selection was thought to be a conservative force that prevented changes to species because mutants usually were less fit.

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  20. Examples of convergent evolution could be considered evidence of situations where evolution is not random. If two species evolve the same feature isn't that more suggestive of necessity than chance?

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