You write: Since we must first assume the rocks are old enough to
be measured, the measuring device cannot be used to prove that the rock is
old. Yet Kulp appears to do just that. Radiometric dating proves an old
earth, but an old earth must first be assumed in order to use radiometric
dating. Wasn't Kulp aware of this false twist of logic? Surely such a highly
educated and knowledgeable student of the sciences would not make such a
glaring mistake as this. Or, Did Numbers misrepresent Kulp's position?
I don't see this as a "false twist in logic." You don't have to
assume an old earth to use any age dating technique but it saves a lot of
time if you make at least some assumptions. For example, the half life of
Na-24 is 15 hours and I could waste a lot of time looking for Na-24 in
minerals if I did not assume that the earth was older than 5 x15 = 75 hours
(I'm using five half lives as a reasonable maximum in measuring ages). So,
I might pick C-14, with a half life of 5730 hours and, if I didn't find any
C-14 in calcites, could assume that the calcite is older than 28000 years
and so on. On the other end of the spectrum, I could use Te-130, which has
a half life of ~1021 years but I might not live long enough to observe
enough disintegrations to draw any conclusions.
Yes, one has to assume that half lives do not change with time but
there has been enough work done on comparing C-14 concentrations with
counting rings in bristlecone pines to prove the point for C-14. I would
think that it would be up to an opponents to age dating techniques to prove
that half lives are not constant.
To me, the best argument for an old earth is still the Oklo
phenomenon in Gabon, Africa, where a spontaneous nuclear fissioning process
occurred in nature. Because U-235 has a shorter half life than U-238, the
U-235/238 ratio was higher in the past. At that time, the U-235/238 was
high enough to sustain this process using natural water as a moderator.
Nowadays, we have to either enrich the fuel by increasing the U-235/238
ratio (US nuclear reactors) or use heavy water as moderator (Canadian
nuclear reactors) to obtain a sustaining chain reaction.
Hope this will help.
Chuck Vandergraaf
Pinawa, MB
Canada