Vagueness, Open texture and Computational dialectics

In this paper we are seeking general definitions of vagueness. They have much to do with dialectical reasoning since we are interested in vagueness caused by differing opinions, or points of view, about the definition of concepts. After giving three definitions for vagueness we sketch ways of choosing meaning for vague concepts, using “direct democracy”. In this context we also define open texture and a related concept, porosity. I am currently working on my Ph.D. thesis at the University of Montreal under the direction of Paul Bratley, of the Département d’informatique et de recherche opérationnelle, and Daniel Poulin of the Centre de recherche en droit public. Our team’s main subject of research is legal interpretation with differing points of view to reproduce the adversarial dimension in legal reasoning (see [Bratley 94] and [Poulin 93]). This paper is an offspring of that work. 1) Vagueness and Open texture Although vagueness is a vague concept, this section contains a few “natural language” definitions intended to shed some light on the subject. Quoting Susskind ([Susskind 87], p. 187), vagueness can be seen as a form of apparent imprecision: [...] words are vague when they clearly have no definite set of necessary and sufficient conditions governing their use and application. Terms such as ‘fair’ and ‘reasonable’, in this sense, can be seen as vague. We can say that concepts are vague because their meaning is varying along time, points of view, application domains, etc. The variations make impossible to cast single definitions with fixed necessary and sufficient conditions. Open texture, then, is a possibility of vagueness (id., quoting Waismann):