Motivation and demotivation of a four-valued logic

Abstract

Belnap offers two arguments for the usefulness of four-valued logic. I argue that one of them, which rests on interpreting valuations as states of our information, when taken seriously collapses into an argument for two-valued logic in which relevance is lost, and that the other, resting on Scott’s thesis, is not an argument for its usefulness. © 1990 by the University of Notre Dame. All rights reserved.