Re: [asa] historical versus experimental sciences

David:

Some quick replies:

"We can be confident, based on evolution, that primates are the best place
to look for something chemically as well as physically similar to us".

We could be equally confident without evolution. Aristotle and Linnaeus
were both capable of seeing that primates and man had a lot in common.

"Overall, morphological study still guides a lot of our understanding of the
overall evolutionary picture."

In other words, if two organisms are a lot alike morphologically, they are
probably close evolutionary relatives. And from that we can deduce that
they will be alike in other ways as well. But we hardly need the middle
step (about being evolutionary relatives) to infer that tigers and lions,
moose and elk, oranges and tangerines will probably be alike in ways other
than their shape.

Regarding the liver example, I prefaced it by "if (let's say)". Given the
premise, the logic was impeccable. If the premise was faulty, then delete
the example; I could come up with thousands more. And the point was equally
made in my example of the broken bone, which apparently is not objectionable
to you. So if you understand the point, why quibble over one of two
examples?

The point is that medical applications of biology proceed from empirical
knowledge of how the creature's organs and systems work. That is, they
proceed from physiology, anatomy, developmental biology, genetics, etc. If
we know that gene number X5B97 (I'm making that up, because I don't know the
labelling system for identifying individual genes) causes such and such a
kind of cancer, then whether that gene evolved in the Mesozoic or the
Cenozoic, whether it was originally transferred to human beings by a virus,
or whatever, is all irrelevant. Wherever it came from, it's now a permanent
fixture in the patient's genome, and it's killing the patient, and either we
can treat the cancer or we cannot. If we cannot, the patient dies. If we
can, the patient may live. And no physician is going to phone up Allen Orr
or Jerry Coyne or Richard Dawkins in order to get evolutionary advice on how
to treat the cancer, if it's treatable. They're going to read up on it in
specialized texts in physiology, biochemistry, oncology, etc., written by
people who actually know something about the day-to-day functioning of human
bodies. They will save the patient, if they do, by thinking like engineers
or auto mechanics, not by thinking like evolutionary theorists.

I'm sorry, David, but your case for the practical uses of evolutionary
theory is weak. Nothing you've said in multiple posts convinces me that a
Ph.D. in evolutionary biology has any advantage, when it comes to practical
applications, over an intelligent generalist with empirical biological
knowledge and plain old common sense. I myself would have tried a
morphologically similar fruit fly in the search for the right pheromone to
save the crops, and evolutionary theory would never have entered my head.
And I've already said that I don't think evolutionary biology needs
practical applications to justify itself, any more than Newton needed to
send up a satellite in 1695 to justify his theory of celestial mechanics.
My point is merely that nobody expects evolutionary theory to be practical,
any more than they expect the Big Bang theory to be practical, so Darwinians
are wasting their breath trying to sell it to the public on that basis.
They have to try to sell it to the public on the basis that it is true,
i.e., that it accurately describes what happened in the past upon this
planet. And the way to do that is to *provide the detailed, stepwise,
genetic mechanisms which can explain the origin of major organs and systems
and body plans*. Until they can do this, they have only themselves to blame
for the fact that half of the American public finds the theory incredible.

Cameron.

----- Original Message -----
From: "David Campbell" <pleuronaia@gmail.com>
To: "asa" <asa@calvin.edu>
Sent: Monday, August 10, 2009 1:00 PM
Subject: Re: [asa] historical versus experimental sciences

>>> Sure, Behe would grant that if you know (a) that two creatures are
>>> evolutionarily related, then you could predict (b) that they will have
>>> many
>>> of the same base sequences, and therefore (c) that they will generate
>>> many
>>> of the same proteins. But the first step is gratuitous. If you know they
>>> have the same base sequences, the information that they are evolutionary
>>> relatives is irrelevant to predicting the proteins. You can get to (c)
>>> from
>>> (b). You don't need (a).
>
> But we rarely know b. And a tells us which creatures are likely to be
> the best match. For example, if you want to find something similar to
> a human protein but a little bit different, evolution tells us to look
> at primates. We have no genetic data whatsoever on millions of
> species of organisms, but we can be confident, based on evolution,
> that primates are the best place to look for something chemically as
> well as physically similar to us. Rodent are pretty close and
> generally much easier to keep in the lab, so practical considerations
> might favor mice (or, for that matter, even more distant organisms).
>
> More fundamentally, the question is what you want to do. Of course
> you don't need (a) to get from (b) to (c). (a) helps you get to (b),
> though one could try to get there empirically. (a) is therefore not
> totally irrelevant, gratuitous, etc. If you want to focus on b to c
> type problems, you can, but this does not make (a) wrong, imaginary,
> or useless.
>
>> Maybe it is possible to have a strong hunch that (a) is true without
>> having all the details of (b), <
>
> Yes, many organisms still have not been investigated with molecular
> techniques, and the vast majority of those that have been studied have
> only a handful of genes sequenced, at most. Overall, morphological
> data still guides a lot of our understanding of the overall
> evolutionary picture. There is no a priori non-evolutionary reason to
> expect a general molecular similarity between morphologically similar
> organisms above and beyond any functional constraints.
>
>>> If a physician knows that a patient has cancer of the liver, and if
>>> (let's
>>> say) it happens that cancer of the liver, once begun, always proceeds in
>>> certain ways, and can only be arrested by certain means, does the
>>> physician
>>> need to know whether the person got the liver cancer from an inherited
>>> genetic defect, from working in a certain chemical factory, or from
>>> fallout
>>> from Chernobyl?
>
> In fact, this isn't a good example, either. In the case of an
> inherited genetic defect, the patient's entire liver consists of cells
> that are prone to becoming cancerous. While the immediate treatment
> may be the same, longer-term efforts at preventing recurrence will be
> different. On the other hand, the chemical factory or Chernobyl
> causes would suggest higher risk of other problems such as genetically
> unrelated cancers.
>
> --
> Dr. David Campbell
> 425 Scientific Collections
> University of Alabama
> "I think of my happy condition, surrounded by acres of clams"
>
>
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Received on Mon Aug 10 14:25:58 2009