nicely sidestepped sciencegeek. just in case anyone does not know, dating methods as c14 etc operate by measurements taken in the present, but do not tell you any unseens in the unobservable past. these are subject to interpretations controlled by assumptions.
to simplify,,, for MY sake. if you saw an hourglass with sand running through, you might calculate how long it had been running, but supposing some sand had been added or subtracted, or the flow had been slowed or speeded somehow, then your calculation would be out. you were not there to observe the whole time.
you, nor I were in the long gone past, so only assumptions can be made about the amounts and conditions in the past.
and as I said, some results have been spectacularly wrong. I certainly hope that if I have to go into hospital that the doctors practise much better science than that. and if I have to have an MRI scan, I can be thankful that it had a creationist inventor !.