Of the various accounts of negation that have been offered by logicians in the history of Western logic, that of negation as cancellation is a very distinctive one, quite different from the explosive accounts of modern "classical" and intuitionist logics, and from the accounts offered in standard relevant and paraconsistent logics. Despite its ancient origin, however, a precise understanding of the notion is still wanting. The first half of this paper offers one. Both conceptually and historically, the account of negation (...) as cancellation is intimately connected with connexivist principles such as ¬( ¬). Despite this, standard connexivist logics incorporate quite different accounts of negation. The second half of the paper shows how the cancellation account of negation of the first part gives rise to a semantics for a simple connexivist logic. (shrink)

Abstract Utterances of counterfactual conditionals are typically attended by the information that their antecedents are false. But there is as yet no account of the source of this information that is both detailed and complete. This paper describes the problem of counterfactual antecedent falsity and argues that the problem can be addressed by appeal to an adequate account of the presuppositions of various competing conditional constructions. It argues that indicative conditionals presuppose that their antecedents are epistemically possible, while subjunctive conditionals (...) bear no presupposition. Given this arrangement, utterance of the counterfactual results in an antipresupposition, that is, a scalar implicature generated from the presuppositions of competing alternatives rather than from the at-issue content of competing alternatives. The content of the antipresupposition is the negation of the presupposition of the competing indicative, i.e., that the antecedent of the conditional is known to be false by the speaker. (shrink)

Connexive logics aim to capture important logical intuitions, intuitions that can be traced back to antiquity. However, the requirements that are imposed on connexive logic are actually not enough to do justice to these intuitions, as I will argue. I will suggest how these demands should be strengthened.

A philosophical discussion of the intuitive meaning of the formalism of modal propositional logics.