Categorical Propositions

Abstract

‘Proposition’ was commonly defined in terms of truth. Paul of Venice, for example, following a long tradition, said that a proposition is ‘indicative speech signifying something true or something false’. For an item of speech to signify something true or something false, that item must have an appropriate logical form. Such forms were extensively investigated, and were generally expounded in a recursive manner. That is, a given form was specified as minimally sufficient if the item of speech was to be able to signify something true or something false, and other forms were described in terms of operations carried out on items of speech which could signify something true or something false. This chapter focuses on categorical propositions, each of which consists of just three parts: subject, copula, and predicate. Categorical propositions are compared with molecular propositions, and three kinds of supposition—personal, simple, and material—are considered. Personal supposition, negation, and modal propositions are also discussed.