Notes on Modal Contextualism

Just as the scope of possible worlds under consideration can be varied according to the type of possibility, whether logical, physical, or social, so it can be limited by the application of possibility as evidence for or against a proposition, whether both for and against are allowed, or only for, or only against. So, the skeptical hypothesis has a different modal scope from ordinary hypotheses in the same way that physical possibility has a different modal scope from logical possibility.

Label all those possible worlds that disprove the skeptical hypothesis SH as DP. The set of possible worlds DP is excluded under a SH context, just as a set of possible worlds in which the laws of physics do not obtain are excluded from a physical possibility context. In effect for the SH, the type of possibility is limited to that which proves the SH. All possible evidence that disproves it is categorically excluded. So, this is a new proof-of-SH, PSH, possible worlds set type that we are limited to considering. When we are permitted the broader scope of possible worlds that include DPSH possible worlds, we exit the SH context.

“Suppose you are in a skeptical scenario” is the same as saying, “For the sake of argument, exclude possible worlds that would disprove you are in a skeptical scenario.” Then, to exit the SH context, one only has to say, “I am now including possible worlds that would disprove that I am in a skeptical scenario.”