Minds and Machines

, Volume 11, Issue 4, pp 577-595

First online:

Real Logic is Nonmonotonic

  • Henry E. KyburgJr.Affiliated withDepartment of Philosophy, University of Rochester and The Institute for Human and Machine Intelligence

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Charles Morgan has argued that nonmonotonic logic is ``impossible''. We show here that those arguments are mistaken, and that Morgan's preferred alternative, the representation of nonmonotonic reasoning by ``presuppositions'' fails to provide a framework in which nonmonotonic reasoning can be constructively criticised. We argue that an inductive logic, based on probabilistic acceptance, offers more than Morgan's approach through presuppositions.