 In epistemic utility theory, the states of the world remain the same, but the possible actions an agent might perform are replaced by the possible epistemic states she might adopt, and the utility function is replaced, for each agent, by an epistemic utility function, which takes a state of the world and a possible epistemic state and returns a measure of the purely epistemic value that the agent attaches to being in that epistemic state at that state of the world. So, in epistemic utility theory, we appeal to epistemic utility to ask which of a range of possible epistemic states it is rational to adopt, just as in traditional utility theory we appeal to non-epistemic, pragmatic utility to ask which of a range of possible actions it is rational to perform. In fact, we will often talk of epistemic disutility rather than epistemic utility in this entry. But it is easy to translate between them. If \(\mathfrak{EU}\) is an epistemic utility function, then \(-\mathfrak{EU}\) is an epistemic disutility function, and vice versa.