It is dangerous to attach probability zero to anything other than a logical impossibility. - Dennis Lindley

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

It is not surprising that in talking about uncertainty we should lean heavily on facts, just as the court of law does when interrogating witnesses. Facts form a sort of bedrock on which we can build the shifting sands of uncertainty.