 If you grant the existence of self-locating beliefs, then it’s clear that people can systematically and predictably give voice to their self-locating beliefs by using the right sentences of natural language. For example, when Muhammad Ali says “I am the greatest”, he’s giving voice to a particular self-locating belief—what Lewis will characterize as a self-attribution of being the greatest, and what Perry will characterize as being in the “I am the greatest” belief-state. Similarly when I call the friend I’m supposed to be meeting at the bar and say, “I’ll be there in 15 minutes”.