In this controversial volume (originally published in 1975), Peter Unger suggests that, not only can nothing ever be known, but no one can ever have a reason at all for anything. A consequence of this is that we cannot have any realistic emotional ties: it can never be conclusively said that someone is happy or sad about anything. Finally, he argues that no one can ever say, let alone believe, that anything is the case. In order to get beyond this apparent bind - and this condition of ignorance - Unger proposes a radical departure from the linguistic and epistemological systems we have become accustomed to. Epistemologists, as well as philosophers of mind and language will undoubtedly find in this study of the limitations of language an invaluable philosophical perspective.