Group Belief -- Broadening Label-based Argumentation Semantics with May-Must Scales -- Semirings of Evidence -- Logic Programming, Argumentation and Human Reasoning -- Reasoning about Degrees of Con rmation -- Ideal related algebras and their logics { Extended abstract -- Computer-supported Analysis of Arguments in Climate Engineering.-A Logic of Knowledge and Belief Based on Abstract Arguments -- A Meta-level Annotation Language for Legal Texts -- Towards an Executable Methodology for the Formalization of Legal Texts -- Goal-driven Structured Argumentation for Patient Management in a Multimorbidity Setting -- Intuitionistic-Bayesian Semantics of First-Order Logic for Generics -- Ambiguity Preference and Context Learning in Uncertain Signaling.-A Decidable Multi-Agent Logic for Reasoning about Actions, Instruments, and Norms -- Preservation of Admissibility with Rationality and Feasibility Constraints -- Uncertainty in Argumentation Schemes: Negative Consequences and Basic Slippery Slope -- Reasoning as Speech Acts -- Dynamics of Fuzzy Argumentation Frameworks -- Probabilistic three-value argumentation frameworks -- Further Steps Towards a Logic of Polarization in Social Networks -- A Formalization of the Slippery Slope Argument.

This book constitutes the refereed proceedings of the Third International Conference on Logic and Argumentation, CLAR 2020, held in Hangzhou, China, in April 2020. The 14 full and 7 short papers presented were carefully reviewed and selected from 31 submissions. The papers cover the focus of the CLAR series, including formal models of argumentation, logics for decision making and uncertainreasoning, formal models of evidence, con rmation, and justi cation, logics forgroup cognition and social network, reasoning about norms, formal representationsof natural language and legal texts, as well as applications of argumentationon climate engineering.