Sensitivity,Safety, and Brains in Vats

Both sensitivity and safety theorists concur that their accounts should be relativized to the same method that one employs in the actual world. However, properly individuating methods has proven to be a tricky matter. In this regard, Nozick (Philosophical Explanations, Harvard University Press, Cambridge, 1981) proposes a Same-Experience-Same-Method Principle: if the experiences associated with two method tokens are the same, they are of the same type of method. This principle, however, has been widely rejected by recent safety and sensitivity theorists. In this paper, I raise an argument in favor of Nozick: not endorsing the principle leads to some rather implausible consequences when certain skeptical scenarios are considered—i.e., scenarios in which skeptical possibilities are ‘close’. Additionally, this argument reveals some important lessons about skepticism in general and the place of modal accounts of knowledge in the internalism/externalism debate.