This paper presents a semantical analysis of the Weak Kleene Logics Kw3 and PWK from the tradition of Bochvar and Halldén. These are three-valued logics in which a formula takes the third value if at least one of its components does. The paper establishes two main results: a characterisation result for the relation of logical con- sequence in PWK – that is, we individuate necessary and sufficient conditions for a set.

In this article we revisit a number of disputes regarding significance logics---i.e., inferential frameworks capable of handling meaningless, although grammatical, sentences---that took place in a series of articles most of which appeared in the Australasian Journal of Philosophy between 1966 and 1978. These debates concern (i) the way in which logical consequence ought to be approached in the context of a significance logic, and (ii) the way in which the logical vocabulary has to be modified (either by restricting some notions, (...) or by adding some vocabulary) to keep as much of Classical Logic as possible. Our aim is to show that the divisions arising from these disputes can be dissolved in the context of a novel and intuitive proposal that we put forward. (shrink)

In this paper it is argued that herzberger's general theory of presupposition may be successfully applied to category mistakes. The study offers an alternative to thomason's supervaluation treatment of sortal presupposition and as an indirect measure of the relative merits of the two-Dimensional theory to supervaluations. Bivalent, Three-Valued matrix, And supervaluation accounts are compared to the two-Dimensional theory according to three criteria: (1) abstraction from linguistic behavior, (2) conformity of technical to preanalytic distinctions, And (3) ability to capture classical logic. (...) A matrix like characterization of thomason's theory is reported. (shrink)