While there is no proof that the rates were different in the past than they are today, there is also no proof that they were the same.Thus radioactive dating relies purely on assumptions.Carbon-14 comes from nitrogen and is independent of the carbon-12 reservoir.If even a small percentage of the limestone deposits were still in the form of living marine organisms at the time of the Flood, then the small amount of carbon-14 would have mixed with a much larger carbon-12 reservoir, thus resulting in a drastically reduced ratio.They will argue that the clock was not reset if the age is too old, or that isotopes were selectively removed if the age turns out to be too young.
d) Even if the rate of decay is constant, without knowledge of the exact ratio of carbon-12 to carbon-14in the initial sample, the dating technique is subject to question.
Elements can be transported into a sample or leach out of a sample.
Scientists will reject theories about the age of the earth that do not conform to the norm.
But, carbon dating can't be used to date either rocks or fossils.
It is only useful for once-living things which still contain carbon, like flesh or bone or wood.