1) That the price of decay was constant throughout time. 2). That the isotope abundances when you look at the specimen dated haven’t been changed during its history by addition or elimination of either moms and dad or daughter isotopes 3) that whenever the stone first formed it included a known amount of child product («Radioisotopes while the chronilogical age of the planet earth» pg v)
We ought to observe that processes that are past never be occurring at all today, and that some might have occurred at rates and intensities far not the same as comparable procedures today. ( «Radioisotopes in addition to chronilogical age of the planet earth» pg vii)