 Recall that on the mapping conception, a narrow content is a function from environments or contexts of acquisition to broad contents. Broad contents in turn are thought of as determining truth conditions; that is, a broad content will be true in some situations and false in others. How should we think of the environments or contexts that determine broad content, and the situations in which broad contents are true or false? One reasonably natural suggestion is the following. Oscar and Twin Oscar both actually exist (in Putnam’s fantasy), but they have different environments, different contexts of acquisition. We can think of their contexts as including all the objective or nonperspectival facts about the actual world, plus a bit more, namely information about their locations in that world. This may be more information than we need, but it gives us a simple way to characterize contexts, and it is guaranteed to include everything relevant to the contribution of the natural and social environment to the contents of their beliefs. And of course, in addition to the actual contexts of Oscar and Twin Oscar, we can consider other possible contexts, other environments that they might have inhabited. In general, we can say that a context of an individual at a time is a centered world, a possible world that we regard as centered on the relevant individual and time.