 There is a fourth, application-driven style of argument for norms for credences that seems to be explicit or implicit in the minds of many Bayesians. The idea is that a good argument for the two core Bayesian norms can be obtained by appealing to applications. The goal is to account for a comprehensive range of intuitively good epistemic practices, all done with a simple set of general norms consisting of little or nothing more than the two core Bayesian norms. If this Bayesian normative system is so good that, of the known competitors, it strikes the best balance of those two virtues just mentioned—comprehensiveness and simplicity—then that is a good reason for accepting the two core Bayesian norms. In fact, the method just described is applicable to any norm, for credences or for actions, in epistemology or in ethics. Some philosophers argue that this method in its full generality, called Reflective Equilibrium, is the ultimate method for finding a good reason for or against norms (Goodman 1955; Rawls 1971). For more on this method and its controversies, see the entry on  reflective equilibrium.