Luke Weiger:
> What Arash writes below is correct. I hasten to add, though, that
> Pinker et
> al. are right--if Chomsky's view of our capacity for language is
> correct
> (and most everyone agrees it's roughly right), then the evolutionary
> explanation of its origin will involve adaptation after adaptation.
Arash:
I agree, it seems pretty obvious something so complex as language capability had to be "designed" by natural selection, it has much too specific of an implementation to be just a random by-product of brain size or complexity increasing.
http://mailman.lbo-talk.org/pipermail/lbo-talk/Week-of-Mon-20060605/011649.html
Miles:
I find it highly amusing that Arash is demonstrating the same fallacious reasoning that Intelligent Design enthusiasts use (replace the words "natural selection" in the above sentence with "God" if that's not immediately apparent). It is not the claim of evolutionary theory that all complex traits must be caused by natural selection. To put it simply, sometimes shit just happens; traits can emerge and persist in a species, and those traits may have nothing to do with selection pressures. --Reading the recent threads, I'll go so far as to say that the true opponents of the scientific development of evolutionary theory are not the "cultural fundamentalist" straw men that Justin excoriates, but rather the naive enthusiasts who jump to the conclusion that every discrete, complex trait in a species must be caused by natural selection.
http://mailman.lbo-talk.org/pipermail/lbo-talk/Week-of-Mon-20060605/011686.html
My response:
I guess the lesson here is that before you become highly amused, make sure you’re not highly confused. Natural selection is in fact the only known means for generating complex traits in the sense of complexity I was referring to, “adaptive complexity,” biological organization especially suited to carry out some sophisticated function, one that plausible benefits reproductive fitness. Recasting Luke’s description of “adaptation after adaptation” as “design” does not signify barrowing from the reasoning of intelligent design, I was alluding to the metaphor just as it is used in biology, e.g. adaptive complexity is used synonymously with the terms “complex functional design” and “design.” The analogy to intelligent design just adds to the ignorance involved in this criticism, the only way someone would entertain this kind of argument was if they hadn’t bothered to figure out what was actually wrong with this brand of creationism, you know, the entire basis for rationally opposing it.
First off intelligent design is being confused here with it’s pre-Darwin predecessor, natural theology. As long as there was no better explanation, theologians had a kind of credibility in claiming that the functional complexity found in the nature had to be designed by god, e.g. the eye is so intricately constructed for the task of vision that it must be the work of a divine creator. But a better explanation did come along.
The kind of reasoning natural theology offered wasn’t refuted by exposing a fallacy as Miles claims, there was nothing unsound in assuming this kind of functional organization couldn’t randomly “just happen.” The theory of natural selection just superseded this religious argument as a better explanation for this characteristic of the natural world that was being observed. Despite the attribution of a supernatural cause, natural theology was describing phenomena in need of explanation, John Maynard Smith put it this way when referring to William Paley’s defense of natural theology, "The main task of any theory of evolution is to explain adaptive complexity, that is, to explain the same set of facts that Paley used as evidence of a creator."
It’s exactly because of the way the theory of natural selection diminished the credibility of natural theology, by removing the mystery on which it was premised, that intelligent design takes the approach that it does, it’s advocacy of “irreducibly complexity” is an attempt to bring god back into the picture by fraudulently restricting the scope of what selection can account for. Intelligent design argues that certain cellular systems can’t be considered adaptively complex as they otherwise would be, that these systems are instead irreducibly complex because they are dependent on all their component parts to be functional. Therefore these instances of functional complexity couldn’t have been developed in any intermediary stages and can’t be explained by any current scientific explanation.
But irreducible complexity is a non-starter as a scientific concept, there is no positive evidence that any of the examples intelligent design uses are really irreducible, design proponents just float the idea around a set of biological systems whose evolutionary histories are not yet completely accounted for. In fact one of the popular examples of supposed irreducible complexity, the flagella of eubacteria, has been shown to be reducible, many of its proteins are homologous to another bacterial adaptation. Still the concept of irreducible complexity is useful to the intelligent design movement because it has the veneer of scientific authority, it’s useful in conveying the impression of an actual disagreement within evolutionary biology.
Intelligent design has other approaches where it couches its message in false conclusions from information theory and probability theory, but neither these or the irreducible complexity argument would be seriously countered by claiming that biological complexity, adaptive or otherwise, just happens, this makes no sense in the context of what is being discussed. If Miles is sincerely opposed to intelligent design pseudoscience, then he shouldn’t carelessly offer up improvised, erroneous refutations of it. Evolutionists spend more than enough time writing up carefully laid out arguments to disentangle creationist misinformation, the last thing they need is to have to further clarify misinformation regarding how intelligent design is actually debunked.
Miles:
To put it simply, sometimes shit just happens; traits can emerge and persist in a species, and those traits may have nothing to do with selection pressures.
My response:
Yes, natural selection isn’t solely responsible for making traits permanent in a species, genetic drift can do this too and in a haphazard, “shit happens” fashion. But neither genetic drift nor any other evolutionary process outside of natural selection has any hope of giving you a functional entity like an eye or even a flagellum. Just because there are different modes of evolution doesn’t mean they can all equally render the same effects. All traits are not the work of natural selection, but that doesn’t mean all complex traits (as in complex functional design) aren’t.
Ravi writes:
[Damn, I can't resist jumping in!]
I don't understand the above at all. The use of quotes around "design" seems to hide the fact that it is the implied non-quoted notion of design that gives selection higher capacity than randomness (or more appropriately, higher-order properties). It seems to me not mere chance that presents the similar usage of design here, with that seen in "intelligent design".
http://mailman.lbo-talk.org/pipermail/lbo-talk/Week-of-Mon-20060605/011666.html
My response:
The essential difference is that in intelligent design the term “design” is used literally whereas I am using it metaphorically, as it is used in biology, but even then the usage isn’t really that similar. As you can see in my response to Miles, the term just refers to biological organization to a functional end, in intelligent design some additional criterion like irreducible complexity needs be fulfilled before the word can be used, to distinguish what it is describing from something natural selection could cause. The metaphorical distinction is the exact reason I used quotation marks. Rather than hiding anything, the quotation marks are there to make clear I’m using the word in an irregular sense, that a natural, agentless process is carrying out the functions of design, design without a designer. This usage isn’t at all uncommon in the texts and papers I‘ve read concerning adaptation, both the papers I referred to use it this way,
http://www.wjh.harvard.edu/%7Emnkylab/publications/languagespeech/HauserChomskyFitch.pdf
Hauser-Chomsky-Fitch: would note all living things are *designed* on the basis of highly conserved developmental systems , natural selection is the only known mechanism capable of generating such functional complexes [the argument from *design*]
Pinker-Jackendoff: the language faculty, like other biological systems showing signs of complex adaptive *design*
, evolutionary process in which an ancestral primate *design* was retained
To take it a step further, by your reasoning you should also suspect the term “natural selection” implies a creationist logic. Nature isn’t an agent that really selects anything, there is nothing intentional about the interaction between the environments and organisms that drives this process. Still the concept of selection matches the actual process closely enough to serve as a productive metaphor.