On “Scorekeeping in a Language Game” (1979) and “Truth in Fiction” (1978).
Building on our first half, which covered Ch. 4 of Lewis's book Counterfactuals (1973), we now look to some of Lewis's ideas about language. In his "Scorekeeping in a Language Game" essay, Mark, Wes, Dylan, and guest Matt Teichman consider conversational dynamics, which in part involves thinking about how possible-world talk relates to conversation. The whole point of talking about the "score" of a conversation is not to describe talking as competitive, but to say that there's a shared set of assumptions that we make as we proceed through a conversation, and this set of assumptions (like a score) can change as we go. Some of these assumptions can be described modally in terms of possible worlds. If we're thinking together about a scientific problem (considering the various possible worlds in which one or the other scientific hypothesis is true), we're not considering the possible worlds in which ghosts or the Divine Hand play some direct causal role. But if you suggest such a solution, and I agree to consider it, then the score has shifted, and we're now considering a much wider set of possible worlds.
Lewis gives many examples of the parameters by which the context (the score) may shift, and for instance, we have another go at Austin's performatives as described in ep. 186. While Austin thinks that performatives have no truth value (and by extension, maybe all sentences are performative to some extent, and so truth is not as binary as we've been led to believe), Lewis thinks that uttering a performative changes the score of the conversation so as to, with the new context, make itself true. Before a religious official pronounces that "you are now married," the sentence (not yet uttered) would have been false, at the moment it is uttered (given appropriate circumstances), then it becomes a true sentence.
In "Truth in Fiction," we're considering a specific type of possible world: one created by a writer. Lewis's example is Arthur Conan Doyle's world of Sherlock Holmes. "In the world of Sherlock Holmes" is a particular kind of modal operator, and according to modal logic, it shouldn't be possible for us to conclude things about the real world from statements about that fictive world, and vice versa, but yet we do, for instance, assume that Holmes doesn't have three nostrils, even though none of the stories explicitly mentions his number of nostrils. So that fictive world is not just all the possible worlds in which the things explicitly said in the text are true, but the closest world(s) to ours in which the text is true, meaning that unless he states something that diverges from our actual world, we can assume that what's true about our actual world is also true of the world the author is creating for us.
So you can see how this shared context is related to scorekeeping in a conversation, and Lewis considers some interesting exceptions to the fictive world being like our actual one, as in if he and his audience share a wrong belief about the actual world, then that wrong belief will be part of the shared context: the fictive world will differ from the actual world in that it contains that error. And of course there are other ways that the author can make mistakes, like Watson's war wound isn't always described in the Holmes stories as being in the same place, yet clearly wounds like that don't move, and Doyle is not trying to give us a world of moving wounds. He just made a mistake, meaning that strictly speaking his world isn't "possible" any more than a round square is possible.
End song: "Real Life" by Matt Wilson, as interviewed for Nakedly Examined Music #118.