Now of 500 or so methods that can be used to estimate the earth’s age, radiometric dating yields the greatest age – sometimes by healthy multiples and other times by orders-of-magnitude: earth is nearly 6 orders of magnitude older by the radiometric method, than it is by uranium salts! Given this vast range of scientific age estimates, one might assume that objective criteria had been applied in deciding to prefer a method yielding the oldest age. Otherwise, why not use a method yielding the youngest age? But in searching out the beginnings of the radiometric method, we find that no such criteria were applied. Rather, its justification was based on extreme-antiquity beliefs of such men as Sir George Darwin (Charles Darwin’s son), who proposed the method in 1905.
Therefore, seeing that radiometric dating is not really the only option, let us treat it objectively, as we would any science: by a) proposing it as a hypothesis; by b) deriving its predictions (which are its age dates); and by c) comparing its ages with reality. If it turns out to be consistent and accurate, it should be bound over for further testing; but if it exhibits inconsistency or error, it should be rejected, as would any falsified hypothesis.
a) The radiometric proposition: The time rate of decay of a radioactive “parent” isotope is an unchangeable proportion to the mass of remaining parent isotope. A mass of stable “daughter” product is developed over time in direct proportion to the amount of decayed parent isotope. Thus at any given time, a simple mathematical relationship exists between the ratio of parent-to-daughter product, and the elapsed time since emplacement of the original materials. This relationship can be exploited to calculate elapsed time from emplacement to present, for samples containing suitable elements.
b) Deriving radiometric predictions: Precise measurements of parent-to-daughter ratios in rock samples are made. Current rates of decay are accurately measured, and applied in “time” calculations. However, a variety of assumptions apply, generally falling into three categories: 1) the parent-to-daughter ratio at time of emplacement can be determined; 2) the system is sealed, preventing loss or gain of parent and daughter products; and 3) the decay rate has been constant. Values for the first assumption are derived using primordial conditions, surmised by extrapolating back in time from current conditions through suppositions of uniformity. These suppositions are also used to support the second and third assumptions. Now after having applied these constraints repeatedly over the last century to the radiometric proposition, many ages have been derived, forming a dense baseline of results from which definitive and objective conclusions can be drawn easily.
c) Comparing radiometric ages with reality: Inconsistencies are the rule, sometimes by hundreds of percent among dates that should be nearly identical; and this gulf widens when differing radiometric types are compared (e.g. Potassium-Argon and Rubidium-Strontium from samples in the same strata). But these inconsistencies pale in comparison to absolute errors from samples of known ages. For example, a sample known by independent historical means to be 3,000 years old may test at 1,000,000 years (a 33,000-percent error) if using any type other than radiocarbon dating!
As for radiocarbon dating, archeologists use it only as a last resort because of demonstrable and excessive error. Even so, (postdiluvian) radiocarbon dates are generally much more accurate than any other radiometric types, for two reasons: 1) radiocarbon is used for much “younger” dating, greatly reducing the multiplicity of uniformitarian extrapolation that must be invoked; and 2) it can be calibrated against known artifacts and periods. In contrast, no other radiometric types are calibrated against any date that is definitively or independently known. Also, all other radiometric types are typically extrapolated to supposed ages of literally thousands to one or two millions of times older than the entirety of recorded history!
Conclusion: From a scientifically philosophical viewpoint, even if calibration against actual dates could be performed, it would instill little veracity after a few multiples of extrapolation, let alone to thousands of multiples. Extrapolation is iffy business from the start; but extrapolating to thousands of multiples from an unverifiable baseline is quite literally the theater of the absurd. Evidentially and empirically, lack of self-consistency, alone, falsifies the radiometric proposition. And even if radiometric dates were always self-consistent, measurements of absolute error (from historical samples) still demonstrate extraordinarily large systematic error that would translate to the unverifiable ages. Therefore, the radiometric proposition should be abandoned. Furthermore, there is no reason to prefer earth ages derived from the radiometric method over those estimated by any of the other 500 or so earth-age methods.