Re: [asa] historical versus experimental sciences

Tim:

Your reply, like those of David Campbell, reminds me of why I didn't go into
biology (even though I started university on a science scholarship, with the
intention of possibly studying animal classification and evolution). You
drown me in data and specialist studies of minutiae, when I am trying to
keep you fixed on a line of logic in a particular argument.

It does not matter if you can come up with ten thousand pieces of evidence
for a "scouring mechanism" *after the fact*. Please read my original
argument carefully. Hebert did *not* offer any of the evidence you are
offering. He did not offer any evidence at all. When asked what the
proposed scouring mechanism might be, he said that it was a "science
mystery". That is, he did not have any clear hypothesis of the mechanism,
let alone any proposed ways of testing it. Yet *still*, lacking even a
clear conception of what such a mechanism might be, he proposed it, and he
proposed it (by his own admission) because he did not like the alternative,
which he believed was suggested by his data, i.e., "creationism". (I
suspect that he was including ID in there, but it doesn't matter for my
point, since "creationism" in any form, ID or not, involves the conception
of design.)

I am not saying that it is wrong for scientists *ever* to postulate the
existence of an entity or force that they (as yet) have no evidence for.
Sometimes there are good theoretical reasons for thinking that a thing
should exist, based on other things that are *known* to be true. In such
cases, that is all right with me, as long as the scientists fully admit that
they have no confirming evidence yet. But there is something more going on
here than that. Hebert (based on his exact words here, which is all we have
to go on) postulated this entity *because his own research had revealed
evidence that neo-Darwinism might not be true*. He was postulating this
entity to neutralize the implications of his findings. His postulation was
not naturally generated by the internal logic of Darwinian theory, but by a
crisis in its evidentiary basis.

Of course, you and David Campbell take it for granted that neo-Darwinian
evolution is true, so you see Hebert's procedure as unobjectionable. If
neo-Darwinian evolution is true, then the apparent evidence for
"creationism" in the mitochondrial DNA *must* be misleading, and therefore
some mechanism *must* be postulated to explain that evidence away.

The case is different when you are arguing before a neutral audience which
has not yet made up its mind that neo-Darwinian evolution is true. Before
such an audience, the argument above does not hold. There is no urgency to
postulate an imaginary mechanism if there is no need to assume that
neo-Darwinian theory is true. One can just as well suppose that
"creationism" is true, and that the imaginary mechanism is a desperate
rescue attempt in order to escape the implications of the evidence. To a
neutral audience, Hebert's proposal is highly suspect.

I find that neo-Darwinians are psychologically incapable of imagining that
there could be a neutral audience. They divide the world into true
scientists who can see immediately why neo-Darwinism is true, and religious
obscurantists ("creationists") who stubbornly refuse to admit the evidence
and the implications. This is why you and David Campbell cannot see my
point about Hebert. You cannot place yourselves at the Archimedean point
where one could gaze with a detached theoretical attitude at both Darwinism
and design and remain open as to which is a better explanation (or perhaps
to a third alternative, i.e., that life is best explained by a combination
of neo-Darwinian processes and design). You are not used to a truly
detached theoretical perspective, because your entire area of science
(evolutionary biology) is predicated on a closing down on one group of
theoretical options, and you never need to raise the deeper philosophical
question whether that closing down can be justified; you can get papers
published, win grants, get promotions, receive accolades from the scientific
world, etc. without ever engaging in such troubling reflection.
Evolutionary biology does not require truly Socratic self-criticism.
(Evolutionary biologists criticize each other, to be sure, just as political
theorists in the old U.S.S.R. criticized each other over which version of
Marxism was correct. But just as it was unthinkable for the Soviets to
imagine that Marx himself might be fundamentally wrong, so it is unthinkable
for evolutionary biologists to imagine that Darwin might be fundamentally
wrong.)

Hebert moves one step towards Socratic self-criticism in his acknowledgment
that design is a scientific hypothesis in the sense that it can point to
genuine data which support it (his mitochondrial DNA findings). He realizes
that it is logically parallel to Darwinism as an explanation, and that he
has no non-arbitrary reason for excluding the inference on principle. Right
away, that makes him a good deal more perceptive than many Darwinians, who
still tout the party line of Eugenie Scott and Judge Jones that ID is not
science (except when they run joyously through all the arguments to prove
that it is falsified science, thus contradicting their premise). But,
standing at the cross-roads, and given the choice of following the road not
taken (the Socratic one, which would entail considering the possibility that
the design/Darwinism question is not yet settled), Hebert cringes at the
last moment, and plunges down the familiar route, inventing mechanisms on
the fly as he goes.

Way back in my first year, I think I sensed the deeply anti-Socratic
character of modern biology, and abandoned it for studies in which the mind
was free of preconceived dogmas about how nature works. Hebert's remarks
convince me that I made the right choice.

Cameron.

----- Original Message -----
From: "Tim" <tpi.hormel@comcast.net>
To: "asa" <asa@calvin.edu>
Sent: Saturday, August 22, 2009 12:13 PM
Subject: Re: [asa] historical versus experimental sciences

> Cameron Wybrow wrote:
>> Tim:
>>
>> Were you reading the same article that I was?
>> Dr. Hebert wasn't talking just about the human species. He said:
>>
> Yes, I know.
> Actually, I did the reading one better: I pulled up some scientific
> articles on the subject of mitochondrial gene diversity and read them. As
> I noted in my previous reply, others have confirmed that within-species
> mitochondrial gene variation is often much less than expected for neutral
> theory. As I explained, neutral theory mechanisms are but a subset of
> evolutionary mechanisms.Other mechanisms can predominate. It is really not
> a SWAG (sophisticated wild-assed guess) of Herbert to suppose that the
> data reflects a selective sweep, because it really does display those
> characteristics. Interestingly, it appears that these observations
> generalize to the mitochondria of many species. That suggests that there
> could be common mechanisms behind the phenomena and suggests a means to
> investigate them.
>> [...]Therefore, the results of genetic barcoding tilt more towards
>> "creationism" than neo-Darwinism.
>>
>>
> The results 'tilt' toward the category of 'undetermined'.
>> [...]Nonetheless, Dr. Hebert rejects "creationism".
> Good for him.
>
>> [...] And if you reply, as you may, that new evidence for such a scouring
>> mechanism has come up since then -- though if that's the case, please
>> provide references rather than just asserting it -- that still doesn't
>> change the fact that an *a priori* motive guided the initial invention of
>> the scouring mechanism, not any evidence that one existed, or even could
>> exist. And the *a priori* motive was to make sure that no one would come
>> to "creationist" conclusions from data which, to a fair observer,
>> actually suggested them.
>>
> New evidence? It's called 'selection'. There's also 'hitchiking', which
> can fix unselected genes by virtue of their proximity to selected genes.
> And that's just a couple of many. In the case of mitochondria, that could
> cover pretty much the whole organelle's genome. A good textbook is an
> excellent place to start reading about the many mechanisms that affect
> genetic diversity. Still, here are some papers on the subject.
>
> Science. 2006 Apr 28;312(5773):570-2. Bazin E, Glémin S, Galtier N.
> "Population size does not influence mitochondrial genetic diversity in
> animals"
> http://www.sciencemag.org/cgi/content/abstract/312/5773/570?ck=nck
>
> Here's a section of a Mortiz paper from 2007:
> PLoS Biol. 2004 October; 2(10): e354. C. Moritz & C. Cicero. "DNA
> Barcoding: Promise and Pitfalls"
> http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2259444
>
> "Over 30 years ago, Richard Lewontin concluded that intraspecific
> variation is tightly constrained and recognized that both genetic drift
> and natural selection offer possible explanations for this fact (Lewontin
> 1974). Under genetic drift, recent population bottlenecks could account
> for low intraspecific variation. It might be argued that the low levels of
> mitochondrial variation detected in our study reflect the unique history
> of North American birds, most of which have expanded into their present
> ranges from smaller populations following retreat of glaciers. However,
> restricted intraspecific mitochondrial variation also exists in many
> vertebrate and invertebrate species from tropical, temperate, marine, and
> terrestrial environments (Barrowclough & Shields 1984; Bucklin & Wiebe
> 1998; Meyer & Paulay 2005; Saunders 2005; Hajibabaei et al. 2006),
> implying a more general explanation. Effective population size for nuclear
> genes can reach an asymptotic limit due to linkage; this effect is
> strongest for organisms with large genomes, with the result that the
> effective population size of vertebrates might not exceed 10E4 (Gillespie
> 2000; Lynch et al. 2006). Although not directly applicable to
> mitochondria, this effect does reveal the complexities of estimating
> effective population sizes and predicting the role of drift in scouring
> variation.
>
> Low mitochondrial variation might alternatively (or additionally) reflect
> recurrent selective sweeps; repeated diffusions of new, selectively
> favoured variants across the breeding range of a species could purge
> mitochondrial diversity. Although 98% of the nucleotide differences in COI
> barcode sequences in our study between nearest neighbours were synonymous,
> selection on any nucleotide position in the mitochondrial genome would
> result in the loss of variation in the barcode region because mtDNA is
> inherited as a single linkage group, due to its asexual transmission.
> Mutations in nuclear or mitochondrial loci important in
> nuclear-mitochondrial co-adaptation might be particularly important
> (Catalano et al. 2006). A recent analysis of patterns of substitution in
> nuclear and mtDNA concluded that reduced mitochondrial diversity in
> animals is due to selective sweeps (Bazin et al. 2006). Although these
> authors found no correlation between census population size and
> intraspecific mitochondrial variation, the range of variation was less
> than expected given census population sizes. This latter finding, together
> with our results showing trends toward increased diversity in larger
> populations and older species, imply that genetic drift does influence
> mitochondrial variation, but only weakly."
>
>> [...] The "embarrassment to science" that I spoke of is not that
>> evolutionary theorists consider the *possibility* of explaining
>> biological information in terms of matter and energy alone. The
>> embarrassment lies in their blatant a priorism, their
>> in-advance-of-the-facts certainty that matter-energy explanations alone
>> will be sufficient. To be willing to postulate utterly unknown
>> mechanisms *only because if they do not exist, one's theory will be
>> falsified or seriously weakened*, is desperate and dishonest.
> Just like those developmental biologists who postulated morphogenetic
> gradients before they actually discovered them? Those biologists were
> overwhelmingly committed to physical mechanisms over 'interruptive' divine
> intervention. I think you're actually making a general indictment of
> current science.
>
> I'm going to dig up a letter I wrote to an earlier participant on this
> topic. It discussed the 'morphic resonance' hypothesis developed by Rupert
> Sheldrake to explain some of the questions remaining in developmental
> biology. He perceived an explanatory gap in many current scientific
> explanations and tried to fill them in with a previously unknown (by
> physicists), but universal mechanism. Gusty and likely wrong, at least his
> mechanism had the virtue of making distinguishable, positive predictions.
>
> Regards,
> Tim
>
>
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Received on Sat Aug 22 18:35:55 2009