Abstract

Properly understood, content internalism is the thesis that any difference between the representational contents of two individuals' mental states reduces to a difference in those individuals' intrinsic properties. Some of the strongest arguments against internalism turn on the possibility for two "doppelgangers" –- perfect physical and phenomenal duplicates -– to differ with respect to the contents of those of their mental states that they can express using terms such as "I," "here," and "now." In this paper, I grant the stated possibility, but deny that it poses any threat to internalism. Despite their similarities, doppelgangers differ in some of their intrinsic properties, and it is to such intrinsic differences that differences of indexical content reduce.