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 any… - Dennis Lindley

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.

Whatever way uncertainty is approached, probability is the only sound way to think about it.

It is not merely a question of calculating with probabilities but also one of relating the ingredients of your probability statements to reality. You do not need to think only about p(E|K) but also about the precise nature of E and K.