Re: Constraints (was Re: Adaptationism's Lessons)
Len Piotrowski (lpiotrow@magnus.acs.ohio-state.edu)
Thu, 19 Sep 1996 17:46:53 GMT
In article <51q2sg$edf@panix2.panix.com> pcg@panix.com (Paul Gallagher) writes:
[snip]
>In <51p5r6$15pg@argo.unm.edu> mycol1@unm.edu (Bryant) writes:
>>In article <51n998$ldl@panix2.panix.com>, Paul Gallagher <pcg@panix.com> wrote:
>>And as I've pointed out before in these parts, that's not the kind of
>>prediction I'm talking about. The adaptationist program does not make
>>predictions about future selection. It makes predictions about the
>>"design" (the historical or evolutionary function) of complex traits.
The problem of agency in "design" has been discussed before. The
sociobiological paradigm presents no role for such agency, which ultimately,
as a logical derivative of functional adaptation theory, is the individual.
Individual choice in the retention of a "trait" (like kestrel's capability to
recognize the UV pattern of vole poop and piss trails as associated with a
possible food resource) presents the problem of alternate processes of
selection. Like cultural selection or group selection, these alternative
processes of selection may work in concert with natural selection, but they
may also reduce or eliminate the utility of natural selection entirely as an
explanation for the retention of characteristics, including behavioral. In
fact, there are those scholars of human behavior that claim the processes of
cultural and group selection in human populations completely overshadow the
efficacy of natural selection.
>[snip]
>At the opposite extreme, Loren Rieseberg recreated the species, Helianthus
>anomalus, by breeding the parent species from which it arose as a hybrid.
>
[snip]
My field and lab mentor related to me a story of Polish biologists recreating
the ancestral Pleistocene form of cow from current populations of
the domesticated animal. In this case as well, the action of intense
deterministic selection doesn't seem possible to account for the re-emergence
and retention of the ancestral morphology. But the idea of chromosomal
mechanical constraints doesn't appear involved either since variation is not
limited to a single path as is the case of the sunflowers. All in all, the
two examples point to "something else is going on."
>>Since I've quoted the Spandrels paper to negate an earlier mistake of
>>yours, perhaps you can take my word for my having repeatedly read through
>>it.
>[snip]
>In particular,
>they advocated Seilacher's construction morphology. This is the idea that
>morphological analysis requires morer than functional analysis. Just
>elucidating the function of a trait does not explain it. You need to
>address phylogenetic, structural, ecophenotypic, and chance factors as
>well to get a complete and useful explanation. These latter four factors
>aren't just something holding back adaptation. They're equal players in
>determining the form of an organism.
I might add group and cultural factors to the list of considerations.
>[snip]
>>>Besides, shouldn't you make predictions that will falsify a hypothesis,
>>>not just make predictions? If "jealousy" is in the genes, we might
>>>predict that jealousy should increase fitness - but if it turned out
>>>jealousy didn't increase fitness, that wouldn't prove the hypothesis that
>>>jealousy is in the genes, false.
>>You're assuming current utility. Bad boy.
>I assumed the opposite. The idea is to think up a prediction that if
>proved wrong would falsify the hypothesis that "jealousy is genetic."
>That's what you want to do: test the hypothesis by thinking up
>predictions that would falsify it. If jealousy does not increase fitness,
>that would not prove the hypothesis that jealousy is genetic wrong,
>precisely because you could rescue the hypothesis by saying that it once
>increased fitness, but does not do so currently. So, the fitness test is
>not a falsifiable prediction.
... and therefore not scientific! In as much as it deflects attention away
from the problems inherent in the subject matter of sociobiology, it proffers
the illusion of scientific validity by mimicking scientific method. Well put
Paul! Until we have direct and uncontroversial evidence that human behavior
has a discrete genetic basis, grand hopes of sociobiology overthrowing
anthropology and the social sciences are decidedly premature.
>If I had said, jealousy isn't genetic because it right now doesn't
>increase fitness, then you would be right to say I was assuming current
>utility. But I didn't say that. I said X is logically independent of Y.
>You someone took that to mean if not X, then not Y.
>[snip]
>
>Paul
Cheers,
--Lenny__
|