Abstract

Default logics have been extensively studied, primarily by Artificial Intelligence researchers, as a method of representing a form of common sense reasoning. While the motivation of these studies are general founded on intuitive notions of extended modes of inference, the technical work focuses on how to represent the "theory" determined by a set of defaults, ignoring how to actually reason with defaults. ;In this essay I develop a logic which is dynamic in the way "proofs" are produced, reflecting the fact that an inference which is permissible at one point in a derivation may not be permissible, and may be rejected, at a later point. My approach is an adaptation of the Dynamic Dialectical Logic developed by Diderik Batens