The last digit of "1540 * (1543 * 1542 * 1541 * 1539!)" is 0 and not 7

Updated. (Didn't occur to me it would be so easy.)

Bayesian probabilities don't give you any anchoring to reality, they only give you consistency. If you're willing to abandon consistency as well, they give you precisely nothing whatsoever.

It is unnecessarily black-and-white point of view on consistency. I can improve my consistency a lot without becoming completely consistent. In practice we all compartmentalise.

Probabilities are a tool for talking about uncertainty, they are not uncertainty.

I did certainly not dispute that (if I understand correctly what you mean, which I am not much sure about).

As ad hominem attacks go, that's an interesting one.

The point was, subjective probability is a degree of belief in the proposition; saying "it must be either 0 or 1 by laws of mathematics" rather implies that it is an objective property of the proposition. This seems to signal that you use a non-subjectivist (not necessarily frequentist, my fault) interpretation of probability. We may be then talking about different things. Sorry for ad hominem impression.