Re: Can any Darwinist in this Forum....


"chris thompson" <chris.linthompson@xxxxxxxxx> wrote in message
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On Sep 27, 3:16 pm, "Aerion" <Aer...@xxxxxxxxxxxxx> wrote:
"John Harshman" <jharshman.diespam...@xxxxxxxxxxx> wrote in message

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Bob Casanova wrote:
On Wed, 24 Sep 2008 15:19:24 -0700, the following appeared
in talk.origins, posted by John Harshman
<jharshman.diespam...@xxxxxxxxxxx>:

OK, let's take this from the beginning; I'm getting tangled
up in my opinions vs. your opinions.

Bob Casanova wrote:

<snip>

IMHO refusing to
acknowledge that observations are distinct from explanations
*in practice*, simply because all observations are
inherently mental abstractions of reality, and thus are
inherently also "explanations" in a sense, is a variation of
the former.

Your HO is wrong. Or can you provide an argument, rather than just an
unsupported opinion? How are observations distinct from explanations
in
practice?

OK, is an example good enough for demonstration? Today, 25
Sept 2008, the Dow-Jones Industrial Average closed at
11,022.06, up 196.89 from the close on 24 Sept 2008. These
are facts (observations), and aren't amenable to anyone's
opinion.
Here's a possible explanation: There were more people who
wanted to buy than wanted to sell.

In this case, as in most cases of common experience, the
observation precedes the explanation; this isn't universally
true, since one *may* theorize about something and then go
looking for an instance.

Do you agree that there's a difference between observation
and explanation *in this case*?

I agree that there's a difference between the particular statements.

What are observations in evolutionary biology? And what is "the fact
of
evolution"?

I'm no biologist, but those who are seem to agree in general
that the fact of evolution is the observed change in allele
distribution in a population over generations. Is this
generally correct?

No, I disagree. I would consider "the fact of evolution" to be universal
common descent. Of course you don't observe allele frequency change in
populations. You infer it from other things.

This is something I've suspected for some time. Since allele frequency
is a measure of genetic diversity in a population, how is it possible to
determine the amount of genetic diversity from one generation to
_another_?

Sampling of course. Most animals have considerably shorter generation
times than humans.

This is interesting. The question is why. Some birds live 100 years, some
sea creatures have a longer life span than humans. Turtles can live for
hundreds of years. The answer lies in part to the telomeres. These are
"specalized Dna sections" in a strand at the tip of each chromosome.
Reminiscent of the tip at the ends of a shoe string.
Research has shown that human cells lose one "section" each time they
reproduce. In test tubes somatic cells reproduce about 50 times, then reach
the Hyflick limit and cease to reproduce. Death soon ensues. However,
germ cells are immortal they are passed from generation to generation to
generation endlessly. They never die. Why do turtles lives many 2 and 3
times
longer than humans? Research has shown that one reason is that their
Hyflick limit is far greater than human. There is research into this and
it is reasonable that once researches learn how to restore the sections
lost during reproduction, why germ cells are able to accomplish this
we may be on the way to much greater life spans. Perhaps in a century
or less, aging and death may be as foreign as the black plague, who
knows.

Dogs have a high percentage of diversity "built in", whereas cats have
much less

I wouldn't bet on that. Appearance is about the least valuable
character for predicting genetic diversity.

and especially cheetahs they have virtually none they are
all one closely related species through inbreeding.

All dogs are one species. All domestic cats are one species. All
cheetahs are one species. They are similar genetically due to a
genetic bottleneck about 11,000 years ago. This has forced inbreeding
on cheetahs.

You are absolutely correct. - Thanks Chris!

Chris




Philosophically correct, but even though
something to be acknowledged as true still an impediment to
progress; we don't whip out an abacus (or a clay tablet and
chisel) every time we want to multiply two 7-digit numbers.

You persist in making these irrelevant comparisons. I think there must
be some unexpressed assumption about what I mean by "fact" and
"theory"
on your part, but I don't know what it is.

We seem to be talking somewhat past each other. To me, a
"fact" is an observation of an occurrence, while a
"scientific theory" is a tested explanation of the reason
for that occurrence. Theories *may* become so well-tested
that they can be treated as facts (evolutionary theory,
atomic theory, germ theory, etc), but the realization should
always be present that *any* explanation may be incorrect
(or less than fully correct), while an observation, unless
it can be shown that it didn't actually happen, isn't. If 5
million people observe a lunar eclipse, it happened. If 5
million people explain it self-consistently and identically,
taking into account all known data, the explanation is
*probably* correct, but it may not be. But even if the
explanation turns out to be incorrect, the eclipse still
occurred.

When you say "eclipse" do you mean an event in which the moon appeared
to
darken for a brief period? Because "eclipse" would seem to incorporate
elements of explanation.

I would say that there are very few facts that don't require a theory
behind them to make them into facts. Like the word "eclipse" you use
above.

To address your implied question, ISTM that you have been
saying that *any* observation is a theory, based on the fact
that what we sense is an abstraction of what actually
occurred, since that's how our brains work. I can't refute
this (nor would I want to, since I agree with it), but I
believe it's more useful in practice, and more likely to
minimize faulty communication, to distinguish between
observations (such as the observation that populations
change over time)

How is this observed? Doesn't it have to be abstracted from more direct
observations of many individuals taken at many times? And do we in fact
directly observe alleles at all? Sorry, but they're too small to see.

and explanations (such as the evolutionary
theories derived from this observation) than to call
everything a "theory", especially when discussing such
subjects as evolution, since this doesn't help to get the
point across to the skeptical who say "It's all just a
theory".

Does that help?

Not really. Because the most important facts of evolution are themselves
clearly theories, even by your criteria. It is, for example, a fact that
humans are closely related by descent to chimpanzees. But we can't just
observe that. You seem to have elided from "fact" to "observation"
above.
Are they the same thing?

.

Relevant Pages

  • Re: Can any Darwinist in this Forum....
    ... up in my opinions vs. your opinions. ... Here's a possible explanation: ... that the fact of evolution is the observed change in allele ... When you say "eclipse" do you mean an event in which the moon appeared ...
    (talk.origins)
  • Re: Can any Darwinist in this Forum....
    ... up in my opinions vs. your opinions. ... *in practice*, ... Here's a possible explanation: ... determine the amount of genetic diversity from one generation to _another_? ...
    (talk.origins)
  • Re: Can any Darwinist in this Forum....
    ... up in my opinions vs. your opinions. ... Here's a possible explanation: ... that the fact of evolution is the observed change in allele ... million people observe a lunar eclipse, ...
    (talk.origins)
  • Re: Can any Darwinist in this Forum....
    ... up in my opinions vs. your opinions. ... Here's a possible explanation: ... that the fact of evolution is the observed change in allele ... million people observe a lunar eclipse, ...
    (talk.origins)
  • Re: Can any Darwinist in this Forum....
    ... up in my opinions vs. your opinions. ... *in practice*, ... Here's a possible explanation: ... that the fact of evolution is the observed change in allele ...
    (talk.origins)