The ASPIC+ framework for structured argumentation: a tutorial

This article gives a tutorial introduction to the ASPIC + framework for structured argumentation. The philosophical and conceptual underpinnings of ASPIC + are discussed, the main definitions are illustrated with examples and several ways are discussed to instantiate the framework and to reconstruct other approaches as special cases of the framework. The ASPIC + framework is based on two ideas: the first is that conflicts between arguments are often resolved with explicit preferences, and the second is that arguments are built with two kinds of inference rules: strict, or deductive rules, whose premises guarantee their conclusion, and defeasible rules, whose premises only create a presumption in favour of their conclusion. Accordingly, arguments can in ASPIC + be attacked in three ways: on their uncertain premises, or on their defeasible inferences, or on the conclusions of their defeasible inferences. ASPIC + is not a system but a framework for specifying systems. A main objective of the study of the ASPIC + framework is to identify conditions under which instantiations of the framework satisfy logical consistency and closure properties.