The grand assertion is that you must see the world through probability and that probability is the only guide you need. - Dennis Lindley

In my opinion, it helps enormously to know why something is true, rather than being told it is true, for why should you believe me? Never believe anything on the authority of a single person but seek confirmation — and reason is the best confirmation.

There are some things that you know to be true, and others that you know to be false; yet, despite this extensive knowledge that you have, there remain many things whose truth or falsity is not known to you. We say that you are uncertain about them. You are uncertain, to varying degrees, about everything in the future; much of the past is hidden from you; and there is a lot of the present about which you do not have full information. Uncertainty is everywhere and you cannot escape from it.

Consider the case of a person who holds a view with probability 1. Then coherence says that it is no use having a debate with them because nothing will change their mind.