This amount is often unknown and is one of the downfalls of conventional radiometric dating.
However, isochron dating bypasses this assumption, as explained below. The final condition is the number of atoms of parent and daughter isotopes remaining in the rock and can easily be measured in a lab.
These assumptions include: 1) the initial amount of the daughter isotope is known, 2) neither parent or daughter product has migrated into, or out of, the closed rock system, and 3) decay has occurred at a constant rate over time.
But what if one or some combination of these assumptions is incorrect?
Certainly the majority of scientists accept radiometric dating.
And yet, there is really no scientific reason proving that radiometric dating is correct, and a number of evidences showing that it doesn't work. We'll find that faith in materialism, and rejection of any supernatural activity, is the foundation stone of radiometric analysis, even before any measurements are made.
This will be covered in the chapters, Primitive Environment (chapter 9), and DNA (chapter 10).
Third, evolution of living organisms into more advanced life forms by natural selection or mutations.
Without these observations you cannot be sure that the time is valid.A swimming race illustrates the simple principles involved in measuring time.This swimmer is competing in a 1,500 metre race and we have an accurate, calibrated wristwatch.This was dealt with in the chapter by that name (chapter 1).Second, generation of living organisms from non-living matter, or origin of life.