Process and Policy : Resource - Boundednon

This paper investigates the appropriateness of formal dialectics as a basis for non-monotonic reasoning and defeasible reasoning that takes computational limits seriously. Rules that can come into connict should be regarded as policies, which are inputs to deliberative processes. Dialectical protocols are appropriate for such deliberations when resources are bounded and search is serial. AI, it is claimed here, is now perfectly positioned to correct many misconceptions about reasoning that have resulted from mathematical logic's enormous success in this century: among them, (1) that all reasons are demonstrative, (2) that rational belief is constrained, not constructed, (3) that process and disputation are not essential to reasoning. AI mainly provides new impetus to formalize the alternative (but older) conception of reasoning, and AI provides mechanisms with which to create compelling formalism that describes the control of processes. The technical contributions here are: the partial justiication of dialectic based on controlling search; the observation that non-monotonic reasoning can be subsumed under certain kinds of dialectics; the portrayal of inference in knowledge bases as policy reasoning; the review of logics of dialogue and proposed extensions; and the pre-formal and initial formal discussion of aspects and variations of dialectical systems with non-demonstrative reasons. 1. ARGUMENTS AND DEMONSTRATION Sometimes there is proof; mostly there are arguments. A proof demonstrates its claim once and for all. An argument, in contrast, produces warrant for its claim only when it is eeective, in a context of counterarguments, rebuttal, and further counterargument. It produces warrant as a result of a process which subjects the claim to dispute. 1 This distinction between argument and proof is historically upheld: there is demonstrative reasoning and there is non-demonstrative reasoning. Mathematical proof is the model of demonstration. Demonstrative reasoning has been the basis of mathematically satisfying formal languages. For non-demonstrative reasoning, formal linguistic systems have been developing more slowly in this century. Major historical gures have written about this distinction: from Aristotle, who introduced the study of both; to Thomas Aquinas, whose discussions of argument occurred during a time when, reversing current thought, non-demonstrative reasoning dwarfed demonstrative reasoning as a topic of intellection; to the unsuccessful admonitions of John Maynard Keynes against Russell and Whitehead as they were conscripted under Hilbert's reductionist mathematicism; to Karl Popper's attempt to distinguish respectable study of disputation from Hegelian dialectical metaphysics ; to Alonzo Church's infamous claim of dialectic's intrinsic incompatibility and Nicholas Rescher have been especially …