This chapter discusses John Osbourne (Ozzy)'s paradoxical insanity and the features of his sensory experiences. The question of whether Ozzy can ever know whether he is insane or not falls under the purview of epistemology. Ozzy's predicament is similar to the skeptical scenarios described by the father of modern epistemology, Rene Descartes. Descartes recognized the problem that insanity poses for knowledge, speaking of madmen, whose brains are so damaged by persistent vapours of melancholia. The possibility of skeptical scenarios like Descartes' demon or the sort of insanity that may be afflicting Ozzy threaten the quality of a person's reasons. A solution to Descartes'skeptical worry could offer a way for Ozzy to determine whether he is going insane. Although commonsense view of the world explains the features of sensory experiences, the mere fact that it does so is not enough to keep anyone from falling "Into the Void" of skepticism. © 2013 John Wiley & Sons, Inc.