Stability of Belief

In everyday life we normally express our beliefs in all-or-nothing terms: I believe it is going to rain; I don''t believe that my lottery ticket will win. In other cases, if possible, we resort to numerical probabilities: my degree of belief that it is going to rain is 80%; the probability that I assign to my ticket winning is one in a million. It is an open philosophical question how all-or-nothi...