[Glenn made a long posting about evidence of hunting, habitation and
fire from a few hundred thousand years ago]
>> I don't see how anyone could conclude that the fossil people that
>> you described could be thought of as anything other than just as
>> human as you and I.
There are a few reasons. One is that there is as yet no evidence of
art-work from that far back, and the tools also are less sophisticated
than they are for Homo sapiens. They don't appear to have buried their
dead. Neandertals did, which is why their fossil record is so good.
Homo erectus and archaic Homo sapiens certainly deserve to be called
"human" rather than "ape", but the evidence suggests that although they
had some of the behaviours we associate with human-ness, they weren't
what we would consider "fully human".
>> I have questions about the dating processes. Based on my limited
>> knowledge of them I know there are two very critical pieces of
>> information that must be assumed (and here I assume you are
>> using radiometric dating). One is the amount of radioactive
>> tracer material that the item to be dated had in it at the time
>> it came into being. The other is that none of the tracer material
>> has been removed by groundwater leaching or any other known or as
>> yet unknown natural processes in the thousands or millions of
>> years between then and now. Just how credibly or accurately can
>> these assumptions be made?
I'll reply very generally, since I don't know a lot about the details of
radiometric dating. Geologists do a lot of testing to determine which
methods work with which minerals, and which substances can migrate into
and out of rocks. For an example, an assumption that a mineral
contained zero argon at formation can be tested by observing whether the
same mineral when formed by modern volcanoes ever contains argon (this
is a hypothetical example only).
Also, there are cases where it can be determined that atoms of a
daughter element had to be caused by radioactive decay from a parent
element (and did not initially exist in the rock) because atoms of the
daughter element cannot form in the crystal lattice for that mineral.
To sum up, there are ways of testing whether the assumptions are
justified or not. In addition, isochron dating mostly gets around these
problems because there are multiple data points which must lie on a line
for the isochron date to be valid. Contamination or leaching will cause
the data points to scatter.
-- Jim Foley Symbios Logic, Fort CollinsJim.Foley@symbios.com (303) 223-5100 x9765* 1st 1.11 #4955 * "I am Homer of Borg! Prepare to be...OOooooo! Donuts!!!"