In this paper I urge friends of truth-value gaps and truth-value gluts – proponents of paracomplete and paraconsistent logics – to consider theories not merely as sets of sentences, but as pairs of sets of sentences, or what I call ‘bitheories,’ which keep track not only of what holds according to the theory, but also what fails to hold according to the theory. I explain the connection between ...

The expert witness testifies under oath to tell "the whole truth," yet certain aspects of the legal system itself make this ideal difficult or impossible. The authors present both a philosophical and a practical discussion of the challenges for the expert in attaining this goal. After review of oaths in general and truth-telling in particular, real-life examples are provided to examine the vici...

The natural answer to this question, MacFarlane takes it, is “yes”. I don’t propose to harp on the question of whether MacFarlane has the data right. Let us just assume, for the sake of argument, that he does. Let us further assume that his interpretation of the data is correct—i.e., that these judgments are assessments of the the whole clause and not simply of the prejacent. Granting all this—...

If we adopt a supervaluational semantics for vagueness, what sort of logic results? As it turns out, the answer depends crucially on how the standard notion of validity as truth preservation is recasted. There are several ways of doing that within a supervaluational framework, the main alternative being between ‘global’ construals (e.g., an argument is valid if and only if it preserves truth-un...

The natural answer to this question, MacFarlane takes it, is “yes”. I do not propose to harp on the question of whether MacFarlane has the data right. Let us just assume, for the sake of argument, that he does. Let us further assume that his interpretation of the data is correct—i.e., that these judgments are assessments of the the whole clause and not simply of the prejacent. Granting all this...

Geometry of Interaction (GoI) reacts against the absence of any satisfactory explanation for logic. The usual one is that of a symbolic calculus of truth values, which supposes that truth values preexist and formulas as well. This was later improved into a symbolic calculus of category-theoretic diagrams, what is still unsatisfactory: since this calculus rests upon an oriented rewriting, one si...