Logics: from tolerance to pluralism

• Applicant: Privatdozent Dr. Martin Fischer
• Subject Area: Theoretical Philosophy
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 407312485

Today classical logic is not the only logic, but there is a variety of alternative logics available. In contrast to logical monism, logical pluralism allows for more than one logic to be adequate. The aim of this project is the development of a coherent and nontrivial form of logical pluralism.The thesis of logical pluralism faces several challenges. On the one hand it has to explain the possibility of different argument forms being correct. On the other hand the thesis should not become trivial by accepting that anything goes. Therefore, the specific form of logical pluralism aimed at in this project should not only explain the variety of different logics but moreover enable a fruitful interaction.Starting point of the investigation will be Carnap's principle of tolerance. A historical analysis is the first step towards a modern form of logical pluralism. Carnap's principle of tolerance is based on a meta-perspective on language as well as a language relativism. Both aspects deserve a more thorough investigation.The principle of tolerance is therefore the starting point for a systematic investigation of pluralism. In this systematic part of the project proof-theoretic methods will be employed. With this central technical as well as philosophical questions will be addressed, such as the collapse argument. Moreover, it will be the basis of an elaborated formal theory, in which the central notion of logical consequence will be proof-theoretically explicated via sequent calculi. These parts of the project will then be brought together to a consistent philosophical theory together with an appropriate epistemology and an inferentialist theory of meaning.

• DFG Programme: Research Grants