The Logic of Modality

A. N. Prior

in Formal Logic

Published in print March 1963 | ISBN: 9780198241560
Published online October 2011 | e-ISBN: 9780191680373 | DOI:
The Logic of Modality

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A division of propositions that was given some prominence in the logic of Aristotle and the Schoolmen is that into propositions simply asserting that something is or not so; and ones asserting that something must be, may be, need not be, or cannot be so. The latter are called ‘modal’ propositions. The first section of this chapter describes modality and its resemblance to quantity. The second section examines modality and implication. The third section describes iterated modalities. The fourth section examines combined modality and quantification. The fifth section describes extensions of the notion of modality. The sixth section explores deontic logic.

Keywords: modality; iterated modalities; quantification; deontic logic; implication

Chapter.  14351 words. 

Subjects: Philosophy of Mathematics and Logic

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