Sound of Trumpet wrote:
(snippage)

For evolutionary
biology is a historical science, laden with history's inevitable
imponderables.

Errr, I think I have a quibble with this. Paleontology is really
historical biology, but evolutionary biology itself is not much more
historical than say physics or chemistry. Just do a search on PubMed for
more info.

Sound of Trumpet wrote:

http://www.arn.org/blogs/index.php/2/2006/01/30/lstrongglemgchallenge_to_evolutionary_ps


Challenge to evolutionary psychology: What if the number of human
ancestors is actually small?

by Denyse O'Leary

ARN correspondent

-- [snip]

Another serious practical problem for evolutionary psychology is that
the number of common human ancestors may actually be quite small. For
example, recent research identifies four women as recent common
ancestors of 3.5 million Ashkenazi Jews (2000 mya).

Why is this a problem? Because evolutionary psychology is, in general,
group psychology. If the basic evolutionary psychology thesis were
sound, a group would respond to a given issue (selective baby-killing,
polygamy) by making choices that affects the group's survival and
reproduction. This response is alleged to be encoded in our genes,
turning up later in our thoughts.

This is a really, really bad explanation. Now, as noted in the snipped
portion, a lot of evolutionists regard evolutionary psychology as "not
ready for prime time." And the basic idea of common descent, and the
theory of natural selection as an evolutionary mechanism, do not depend
on whether evo-psych enthusiasts are correct about the selective
regimes that shaped our mental traits, or even about those mental
traits themselves.

But even so, I think if you're going to reject evo psych, it deserves
to be rejected on its own merits, not on the merits of some dimwitted
caricature of the idea.

Evolutionary psychology holds, at a minimum, that human psychology
evolved by the same mechanisms as human physiology. It is not "a group
would ... mak[e] choices" about how to deal with problems. Rather,
within a group, there would be individuals with variant psychological
dispositions, different predilections for behavior under various
conditions. Some traits would make the individuals in the group more
likely to produce a larger percentage of the groups total offspring
than other individuals.

Note that these predispositions to certain behaviors aren't "chosen."
Just as the ancestors of polar bears benefitted by having, e.g. lighter
fur (presumably for camoflage), but no ancestor chose its fur color, so
no human ancestor chose his or her tendencies towards compassion, or
vindictiveness, or or whatever. Each individual chose his own actions,
based on these psychological traits which were, in part, genetically
induced. The responses to social problems are not encoded in our
genes; rather, a tendency to have the sort of mental wiring that tends
to lead to certain decisions, is encoded in our genes.

But if only a few human beings are actually ancestors, only a few
unique and unpredictable individual responses matter. It is no use
theorizing about how early humans in general might have reacted if the
individual who chooses to go against the group becomes the ancestor.
And we don't even know, for mosst purposes, whether a decision that
went against the group played any role in that individual's becoming an
ancestor.

First, note that those four women were probably not the only
ancestresses of modern Ashkenazi Jews. I'm pretty sure that the author
is talking about *mitochondrial* DNA, which is inherited (normally)
only through the female line. Therefore, mitochondrial DNA cannot
reveal anything about male ancestors, or about female ancestors who are
connected to one through sons rather than daughters. The same point
applies to "mitochondrial Eve," the last female-line ancestress of all
living humans. We are probably descended from many of the members of
her tribe alive at her time (and perhaps from members of other tribes
as well), as well as from her; we simply didn't didn't inherit our
mitochondrial DNA from any of them.

Second, I don't think many evolutionary psychology proponents think
that Ashkenazi Jews have unique psychological traits not found in other
humans. But perhaps those four ancestresses did have genes, that
shaped their brains to be predisposed to behaviors that somehow helped
them to leave descendants when some of their contemporaries did not.
We inherit our genes (and therefore, to whatever extent our genes shape
our minds, our predispositions to certain personalities and tendencies,
from specific individuals, not from entire groups.

Who knows how those four Jewish women felt about the persecution of
Jews, for example? The only thing we can say for certain is that they
did not see it as a reason to refuse to have children. Similarly, the
only thing we can safely say about our early human ancestors is that
their challenges and troubles did not dissuade them from raising
families. Who can effectively postdict any other critical details in
the absence of a historical record?

I am not going further than I have in defense of evolutionary
psychology, but I will point out that it is silly in the extreme to
suppose that we cannot discover facts and test theories about things
that happened before historical records. This is a variation on the
tedious and absurd creationist line, "were you there?" If we could not
know things that were not directly observed and reported, there would
be no point to forensic science of any kind, to autopsies or to
crash-scene investigations. I really do not think that Ms. O'Leary
knows what she is talking about.

Sound of Trumpet wrote:

http://www.arn.org/blogs/index.php/2/2006/01/30/lstrongglemgchallenge_to_evolutionary_ps
Challenge to evolutionary psychology: What if the number of human
ancestors is actually small?
by Denyse O'Leary
ARN correspondent

Given that the Bi(b)le says all humans descended from a single
pair of man and woman...