brain sizes: Einstein's and women's
lojbab at lojban.org
Sat Oct 5 23:50:20 EST 2002
"John Knight" <jwknight at polbox.com> wrote:
>"Dave Wilson" <testaccount2002 at btopenworld.com> wrote in message
>news:3D9F5844.6030809 at btopenworld.com...
>> For anything beyond ~50,OOO years, carbon dating is pretty inaccurate,
>> (and even within its usable timescale, it needs organic content, and
>> really is best with calibration from dendrochronology for good accuracy)
>> but radiometric dating using other elements (Potassium/Argon,
>> Argon/Argon, Uranium series, etc) can be used for the longer geological
>> Particularly where the composition of samples and timescales is such
>> that different radiometric methods can be used, a high degree of
>> confidence can be placed in the results.
>> Dave W.
>There are two primary problems with both techniques:
>1) It's assumed that the increase or decrease in radioactivity is a
>constant, and we have NO way to prove that it is.
His point was that different kinds of radioactive dating agree with
each other, and on the shorter time spans, with non-radioactive dating
>2) The ONLY factor (written history) which can be used to calibrate either
>technique is not accurate itself.
Written history is not a particularly useful means of calibration.
Tree rings and glacial deposits go back further.
>There's abundant scienfic evidence that increases and decreases in
>radioactivity are not constant.
>As just one example, recent measurements of
>the changes in the strength of the Earth's magnetic field suggest that the
>magnetic field may have been so strong just 5,000 years ago that space
>radiation may not have even been able to enter the atmosphere.
Even if so, this has nothing to do with the rate of radioactive decay
of carbon-14 or other radioactive isotopes.
>Obviously this would throw the calibration way off.
No it wouldn't.
>On top of that, the
>assumption that any existing written document is older than 2,000 years is
>an ASSUMPTION, so the calibration of organic matter that's associated with a
>2,000 year old written document is based exclusively on an ASSUMPTION that
>cannot be proven with any scientific validity.
The calibration of dating methods is based on using MULTIPLE
independent methods which have to agree with each other to establish
their mutual credibility.
>The third problem, of course, is that 2 people become 6 billion people in a
>big hurry. At the rate of growth of the US, with wars, abortion, and the
>pill, it would take only 1,500 years to go from two people to the current
>world population of 6 billion.
So? Are you claiming that Adam and Eve were born in 500 AD? That is
obvious nonsense. And of course I've provided you numerous references
to show you why human population was nearly flat until a few hundred
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