Abstract

In the First Meditation, the Cartesian meditator temporarily concludes that he cannot know anything, because he cannot discriminate dreaming from waking while he is dreaming. To resist the meditator’s conclusion, one could deploy an asymmetry argument. Following Bernard Williams, one could argue that even if the meditator cannot discriminate dreaming from waking while dreaming, it does not follow that he cannot do it while awake. In general, asymmetry arguments seek to identify an asymmetry between a bad case that is entertained as a ground for doubt and a good case in which one takes oneself to know something. My aim in this paper is to consider how effective asymmetry arguments are as an anti-skeptical strategy. I conclude that although asymmetry arguments provide an effective response to dreaming skepticism, they fail as a response to brains-in-a-vat skepticism