The Price of Twin Earth

Abstract

Abstract Liberals about perceptual contents claim that perceptual experiences can represent kinds and specific, familiar individuals as such; they also claim that the representation of an individual or kind as such by a perceptual experience will be reflected in the phenomenal character of that experience. Conservatives always deny the latter and sometimes also the former claim. I argue that neither liberals nor conservatives have adequately appreciated how the content internalism/externalism debate bears on their views. I show that perceptual content internalism entails conservativism when conjoined with one other, extremely plausible premise. Hence, liberals are committed to perceptual contents externalism, yet they have failed to fully address the consequences that this has for their view. Moreover, the argument is easily adapted to perceptual experiences of Twin Earthable properties, like colour and shape. I use this last result to show why existing conservative arguments that appeal to Twin Earth plausibly overgeneralize.