 Traditional utility theory (also known as decision theory, see entry on  normative theories of rational choice: expected utility)  explores a particular strategy for establishing the norms that govern which actions it is rational for us to perform in a given situation. Given a particular situation, the framework for the theory includes states of the world that are relevant to the situation, actions that are available to the agent in the situation, and the agent’s utility function, which takes a state of the world and an action and returns a measure of the extent to which she values the outcome of performing that action at that world. We call this measure the utility of the outcome at the world. For example, there might be just two relevant states of the world: one in which it rains and one in which it does not. And there might be just two relevant actions from which to choose: take an umbrella when you leave the house or don’t. Then your utility function will measure how much you value the outcomes of each action at each state of the world: that is, it will give the value of being in the rain without an umbrella, being in the rain with an umbrella, being with an umbrella when there is no rain, and being without an umbrella when there is no rain. With this framework in hand, we can state certain very general norms of action in terms of it. For instance, we might say that an agent ought not to perform an action if there is some other action that has greater utility than it at every possible state of the world. This norm is called Naive Dominance. We will have a lot to say about it in  section 5.1  below.