 Lewis’s suggestion about how to think of self-locating mental states has recently been very influential in a variety of areas. Adam Elga (2001, 2004) has extensively investigated the consequences of Lewis’s approach for decision theory. Andy Egan (2007) has developed a novel form of semantic relativism using Lewis’s approach as a model. Daniel Nolan (2007) has recently argued that Lewis’s approach is less plausible for desire than for belief, and Robert Stalnaker (2008) argues that the view makes the wrong judgments about sameness and difference of belief across agents and times.