If 14C is in diamonds or coal they can not be as old as claimed or the decay rate has varied over time in a significant way. One or the other.
Unless that residual C14 is coming from various contaminants and instrumentation residues. Then where are you?
If radio active decay varied at all, even .01% (not just error in measurement) then the principle of radio decay invariance is nonsense.
But C14 ages are calibrated against the calibration curve, so any such factors are taken into account in the resulting date. And that right there is enough to blow the 6000 year belief right out of the water.
Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
How can I possibly put a new idea into your heads, if I do not first remove your delusions?--Robert A. Heinlein
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" does not include the American culture. That is what it is against.