Though some doubts about the principle that every proposition is either true or false were entertained even by Aristotle, both the number and the vigor of criticisms of this principle have been increasing in recent years. This paper attempts a restatement and a re-examination of the issues involved in this dispute, and in particular an evaluation of the effects on the argument of such recent discoveries as that of the “many-valued logics.”.

Charles A. Baylis; VII—Foundations For a Presentative Theory of Perception and Sensation, Proceedings of the Aristotelian Society, Volume 66, Issue 1, 1 June 19.