Introduction: Fundamental Uncertainty and Plausible Reasoning

Uncertainty and rationality are closely related features of human decision making. Many practical decisions are traditionally reconstructed as attempts to frame uncertain outcomes within the domain of rule-constrained reasoning, and much established literature explores the manifold ramifications of rationality when choice among uncertain outcomes has to be made (as with choice criteria associated with maximization of expected utility). However, this overall picture is changing rapidly as a result of recent work in a variety of related disciplines. Research in cognitive science, artificial intelligence, philosophy and economics has called attention to the open-ended structure of rationality. This point of view stresses the active role of the human mind in developing conceptual possibilities relevant to problem solving under contingent sets of constraints. Rationality is conceived of as a pragmatic attitude that is nonetheless conducive to rigorous investigation of decision making. In particular, conditions for rational decision are moved back to its cognitive frame (the collection of concepts and predicates that makes any given representation of problem space possible), and the cognitive frame is associated with the context-dependent utilization of cognitive abilities. This view of rationality distances itself from received conceptions of deductive and inductive inference as it is related to a situational conception of reasoning.