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 (
1978
), 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.