Disagreement in logic and reasoning

State of the art and the proposal

Disagreement is a relatively new topic in philosophy, although the concept of disagreement is obviously at the heart of a number of classical philosophical questionnings. In the last twenty years, the concept of disagreement has been the focus of a growing number of studies. A large part of the philosophical community has taken up the issue and arrived to a conceptual circumscription of the notion of disagreement. The analysis of disagreement is now also applied to concrete cases such as the explanation of disagreements between experts, the reduction of disagreement or the detection of psychological or sociological origins of disagreements, the tasks and methods of conciliation, etc.

However, most studies on disagreement have focused on the epistemology of disagreement or issues relative to opinion and belief. Very few projects have been devoted to disagreement in science. The main proposal of the DISAGREE project is to innovate and develop an analysis of disagreements concerning logic and reasonning, i.e. the very principles which are supposed to make possible a resolution of disagreements. It thus focuses on the limit cases of disagreement and in domains where disagreement is usually not expected, such as science, logic, and mathematics, or in situations where the possibility of overcoming a disagreement seems problematic. Although the goal is not the resolution of actual cases of disagreement, the ambition is to elaborate a theory of disagreement which will not be disconnected from practical applications.

Scientific goal

Situations of disagreement are not necessarily negative in themselves, and they may even have virtues in terms of competition and heuristics. However, the concept of disagreement is essentially linked to the idea of an effort towards its own overcoming, by means such as debates, negociation, evaluation of arguments, and justification, rather than by strength, force, or violence. For this reason, disagreement is inseparable from reasoning, rational discussion, argumentation, and, in some cases, proof and refutation. The originality of the DISAGREE project is to focus the analysis of disagreement on the very conditions which are usually presupposed for its resolution or in which these conditions seem impossible to satisfy. These cases of disagreement concern the very principles of argumentation, of proof, of logic, and more generally of science. And also, in a completely different perspective, the judgement of taste in the precise cases where one does not see how to make sense of some possible argument intended to convince (de gustibus non disputendum, as people commonly say), and where all that seems to remain is a kind of radical and irreducible divergence (to be distinguished from disagreement), which can only be reduced to some kind of relativity. In such cases, the issue is to question the limits of such relativity and its possible overcoming. Are such divergences cases of disagreement ? or should they be opposed to cases of disagreement ? Oddly enough, this field of research, in its globality, is almost unexplored and calls for a large scale investigation and structure.

With this leading idea in mind, we propose to divide our investigations into several main axes which can just be quickly enumerated here and are explained in many details in the complete version of the project: 1) disagreement in judgment and action; 2) disagreement in logic ; 3) disagreement and pluralism; 4) disagreement in mathematics; 5) verbal disputes and deep disagreements; 6) disagreement in science. The research aims to arrive to a detailed analysis of these axes and to clarify and make apparent the large scale goals of their content. This will be made possible through the association of researchers in logic, logic and cognition of reasoning, philosophy of action, psychology of reasoning, philosophy of mathematics, epistemology and philosophy of mind, philosophy of language, coming from the French and Japanese institutions involeved in the project, specializing in different domains, who will apply their own and specific expertise to the analysis of disagreement.