 A second guiding idea is that the proposition actually conveyed by the assertion of a particular sentence depends on presuppositions shared by the participants in the conversation—including presuppositions about what particular words represent and presuppositions about actual empirical circumstances. If you’re a Chinese speaker who doesn’t understand anything at all about what the term ‘cold’ represents in English, then I cannot use ‘It’s cold today‘ to convey facts about Melbourne’s weather. And if you’re a Canadian who doesn’t understand anything about Australian weather conditions, you won’t understand precisely what I am saying to my fellow Melburnians when I assert that sentence. Stalnaker calls the set of presuppositions that conversational partners treat as common knowledge that they can rely on to get their point across the “context set”—which he models as the set of possible worlds that satisfy all of these mutual presuppositions. The context set will encode shared assumptions about the meaning of words, about general empirical facts, about the what’s happened so far in the conversation, and so on.