No it is not Bishop Ussher, it is the Bible. We can all add up the numbers, we don't need Bishop Ussher although his calculations are probably the most trustworthy.
Pat cites the radiometric evidence for an old earth: what is your opinion on radiometric dating?
Pat says you have dinosaur fossils and you have radiocarbon dating and Bishop Ussher is wrong, and you should teach your children what science reveals as evidence of reality.
Of course it isn't just radiocarbon dating, but a whole slew of radiometric and other dating methods that all show the earth is old, very old, and they show it in a consistent pattern, a pattern that cannot be explained by such methods being erroneous or prone to massive errors.
The age of the earth is not a matter of debate, it is a matter of looking at the evidence and either:
(A) accepting the evidence and theories of science as the best consistent explanation, or
(B) rejecting the evidence of virtually every science known in favor of a belief, and an interpretation, that is contradicted by the evidence and theories of science.