 The two Bayesian norms sketched above can be stated a bit more generally as follows. (A formal statement will be provided after this tutorial, in  section 2.)  Suppose that there are some possibilities under consideration, which are mutually exclusive and jointly exhaustive. A proposition under consideration is one that is true or false in each of those possibilities, so it can be identified with the set of the possibilities in which it is true. When those possibilities are finite in number, and when you have credences in all of them, Probabilism takes a simple form, saying that your credences ought to be probabilistic in this sense: