But how do you explain that none of them contradicted each other over two thousand years when defining doctrines concerning faith or morals?
Hey Jacob quick question. How many infallible statements have popes made? The number matters for this argument, you see. If it was only a handful talking about different things, well, no surprise there, of course they don't contradict each other. If there's been hundreds, or thousands, that's certainly interesting. Might be worth a look.
Actually, to make it more precise, since we don't want anyone saying there's been goalpost shifting going on, how many statements by popes are generally agreed by Catholic theologians to be cases of papal infallibility? If we look just at that list we don't have to worry about anyone saying 'well, it's common sense that this one doesn't count'.