[b-hebrew] Language Evolution
peterkirk at qaya.org
Wed Sep 21 12:57:14 EDT 2005
On 21/09/2005 16:35, Read, James C wrote:
> Africa as a basin of life seems credible, although i would disagree
> with the date.
> I come from a highly scientific background (especially chemistry) and
> unimpressed by many dating methods which are dependent on variables
> which we cannot
> claim to have enough knowledge about (e.g. carbon dating is directly
> to the amounts of radiation the substance has been exposed to. as we
> cannot know
> for sure that past exposure was consistent with present exposure we
> cannot rely
> completely on such methods).
Just to clarify, the datings I mention do not depend on radiocarbon,
which is anyway accepted to be useless before about 40,000 years ago -
although the tie-up to the 'Ubaid period probably does so. Some of the
estimated dates are based on genetic estimates which everyone accepts
are highly approximate. But others are based on much more reliable
techniques such as the counting of layers in the ice in Greenland, which
allows very specific dating of climatic changes and anomalies. Some of
the ages are based on a uranium-thorium method. So we have several
independent methods pointing to approximately the same dates. Anyway, my
point is not so much in the precise dating as in the general picture.
peter at qaya.org (personal)
peterkirk at qaya.org (work)
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