He has a good point, Isaiah. There is no evidence of any variation in the decay rates. Also, while there are possible ways of contaminating measurements, the scientists are well aware of these and correct for them. Creationists love to play up possible contaminants, conveniently ignoring the fact that it was mainstream science that located these and has corrected for them. Also, more than one measurement is made. On a tell, for example, they may take at least three samples for carbon-14 dating. In addition, they also bring in other means of dating. If all indicators point the same way, bango, you got it. If not, and sometimes that happens, they you can't reach any definite conclusions. Your comments remind me of a situation that occurred with creationist Barry Settlefield. He tried to argue that c (speed of light) was not absolute, could in fact undergo many changes. He then argued that c was infinite at the beginning of creation and has been slowing down ever since. If scientists took that into account, they would calculate out a very young earth. But where is the evidence of any of this? C has been checked more than once by modern science and remains constant. Setterfiled tried to argue on the basis that the history of C measurements shows slower and slower rates. Doesn't compute. Careful study of the records of attempts to measure c show it has been assumed to be faster and faster, not to mention these measurements were made with primitive instruments. Also, if you ere to throw out all scientific measurements, what would you use in their place? And if scientific measuring techniques prove to be wrong, you can say the substitutes you brought in were any better? If you can't trust one, it stands to reason you should have doubts about the other. Some creationists have appealed to Scripture. However, Scripture provides no clear measurements and has been interpreted as saying anything from 4004 BC to 10,000BC. Incidentally, minor point here: Archbishop James Usher did not say the world began in 4004 BC. That was q decision his followers came up with, not Usher.