Re: Multi-Regional vs. Replacement, was This might be an ev
J. Moore (j#d#.moore@canrem.com)
Sat, 3 Jun 95 12:13:00 -0500
Jo> >I am not doing a "statistical refutal"; I am merely showing the
Jo> >inherent limits of what this worthwhile and important data can show us.
Jo> >Jim Moore (j#d#.moore@canrem.com)
Jo> Fair enough. Does this mean we're both right?
Jo> John A
Of course; actually, we seem to be saying much the same thing when it
comes to conclusions, and at any rate I'm sorry that on re-reading my
posts I did imply (through a bit of lazy language [ie. "your
conclusion"]) that you were initiating a statement rather than reporting
one. Indeed, I think that the two hypotheses should probably be folded
into each other and stirred; and that this is usually what ought to be
done with dueling hypotheses: instead they get caught up with arguments
about the data rather than earnestly trying to fit both sides' data
into a third conclusion.
Jo> Jim, if you're really saying what you seem to be saying, I think you're
Jo> flogging a dead horse :-). Not even the most rabid replacementist would
Jo> claim that the MtDNA evidence showed that it was *impossible* that our
Jo> ancestors were scattered all over at the time under consideration --
Jo> just that it was extremely *improbable*.
But my point is that the data is tracking the effects of a single
lineage, and by doing it backward (which is of course the only way we
have [and probably ever will have] of doing it) we only *seem* to see
a replacement by a new population. This *is* stated, that we have
replacement without admixture by a new population, and is in fact the
replacement theory in a nutshell. Knowing what we do of how both human
and chimp individuals tend to be exogamous, this seems unlikely. What
seems more likely is that Africa has been a wellspring of change for
hominids and that this is what the MtDNA evidence is showing. This is
not the radical new outlook that the MtDNA researchers were setting
forth, as it's just what seemed likely from the fossil evidence that
we've had for some time (ie. the "archaic" *Homo sapiens* fossils).
Unfortunately, getting notice in science generally is easier by saying
that what's reported is radically new and overturns previous thought,
rather than building on previous ideas. This building on previous ideas
can either be supporting them or disaggreeing with them, but it's how
most science, and perhaps all science really, is built. It doesn't get
headlines, sadly, although I think it should.
(For instance, Susman's *Science* paper about the robust
australopithecine fingers' being adapted in a way that suggested
habitual tool use was presented as an "overturns previous thought",
which makes a better, and more likely, headline than "Susman shows that
Tanner was right to say that L. Leakey shouldn't have changed his mind
about what he said in 1959". The second statement is more accurate, and
I think it's more exciting science, but it's not exciting newspaper
reporting I guess. But perhaps scientists shouldn't gear their
statements quite so much toward the newspapers. ;-)
Jm> It does not, however, tell you anything about admixture or the lack of
Jo> ^^^^^^^^
Jm> it, as the MtDNA proponents had claimed, and as is still claimed
Jo> It does tell you *something* about what the other side was *likely* to
Jo> be, given some sort of assumptions about breeding population size, etc.
I just left this in because it clarifies one of the problems that the
replacement theorists have had, that is in making assumptions about
human behavior without seeing what behavior is likely, for instance
by looking at what humans (and our close relatives) actually do. They
assumed the "other side" was always most likely the same group, when
human and ape behavior would suggest it wasn't.
Jim Moore (j#d#.moore@canrem.com)
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