Although arguments for and against competing theories of vagueness often appeal to claims about the use of vague predicates by ordinary speakers, such claims are rarely tested. An exception is Bonini et al. (1999), who report empirical results on the use of vague predicates by Italian speakers, and take the results to count in favor of epistemicism. Yet several methodological difficulties mar their experiments; we outline these problems and devise revised experiments that do not show the same results. We then (...) describe three additional empirical studies that investigate further claims in the literature on vagueness: the hypothesis that speakers confuse ‘P’ with ‘definitely P’, the relative persuasiveness of different formulations of the inductive premise of the Sorites, and the interaction of vague predicates with three different forms of negation. (shrink)

The paper represents main ideas of my theory “Relative verity logic”, that combines advantages of two contrary approaches to vagueness. RVL allows the fruitful treatment of borderline cases while saving all the classical tautologies and inference rules; and on top of all this, it also avoids the trap of the sorites paradoxes.

The dissertation has two parts, each dealing with a problem, namely: 1) What is the most adequate account of fuzziness -the so-called phenomenon of vagueness?, and 2) what is the most plausible solution to the sorites, or heap paradox? I will try to show that fuzzy properties are those which are gradual, amenable to be possessed in a greater or smaller extent. Acknowledgement of degrees in the instantiation of a property allows for a gradual transition from one opposite to the (...) other, each intermediate stage constituting an overlap in certain proportion of both contraries. Hence, degrees in the possession of a property give rise to simple contradictions. The reason why I have chosen those two questions is that they provide the main philosophical motivation for a particular brand of an infinite valued and paraconsistent logic. I will claim that Classical logic (CL) is not adequate to handle fuzzy situations, and, being deficient, is in need of being expanded to make room for degrees of truth and weak contradictions. One can hardly deny the importance of the debate, since what is ultimately at stake is what the limits of truth, rationality, intelligibility and possibility are. The main disciplines within which the research moves are the philosophy of language, philosophy of logic, and ontology. (shrink)

This volume analyzes and studies how vagueness occurs and matters as a specific problem in the context of theories that are primarily about something else.

Purpose. The way of assignment of exact numerical truth value to any vague predicate sentence remains to be problematic. Methodology. I would like to propose one of the possible ways of estimation for vague sentences: to exploit the supevaluationists' idea of precisification for the interpretation of verity. We can think of the verity of a borderline sentence as the proportion of permissible precisifications on which it is true. Scientific novelty. The proposed construal of degrees, interpreting verities on the basis of (...) a measure over admissible precisifications, allows discrimination among borderline cases that would otherwise all inhabit the same truth-value gap. My view of vague expressions assumes also that a borderline sentence may affect verity of another borderline sentence. The notion of relative verity reflects an intuitive assumption about possible semantic connections between applications of vague predicates. So-called forcing connection is a non-symmetric, transitive relation, which does not express any temporal or causal dependence between borderline cases; rather, it expresses a logical or semantic relation. I consider different kinds of forcing connection between vague expressions. Conclusion. Using of the notions “relative verity” and “forcing” provides preservation for borderline sentences of certain logical connections, which are postulated by classical logic. (shrink)