As a reminder, in Bayesian epistemology, given a hypothesis H and new evidence E, it is recommended to update your degree of belief using the formula P (H|E) = (P (E|H) * P(H))/P(E). P (H) is the prior probability of the hypothesis being true. In Bayesian epistemology, there is the concept of a prior for certain theories. A zero prior is not recommended even for theories that have had no evidence so far. This is because with a zero prior, no amount of evidence would change your degree of belief as per that formula.

But how does this materialize into reality? A zero prior in the case of a hypothesis also means you are simply certain that it isn't true. But why does certainty imply that you can't change your mind? It is not hard to imagine someone being certain that dinosaurs did not exist, come across evidence of fossils, then start believing that dinosaurs did exist.

As such, is it wrong to assume that a 100% degree of belief implies that no amount of evidence can change your mind?