On Skepticism and Certainty
Skeptics either have valid reasons for their universal doubting, or they have no valid reasons for it. If they have valid reasons, they surely know something that is valid, and they no longer are real skeptics. If they have no valid reasons, they have no reason to doubt. In the first case their position is inconsistent, and in the second case their position is irrational. Whichever way they turn, their position is untenable. --Celestine N. Bittle, Reality and the Mind , 1936