Two aspects of reasoning competence: A challenge for current accounts and a call for new conceptual tools

Abstract

The initial enquiry into human formal deductive abilities has been more or less fulfilled, yielding a moderately positive answer (people do have some degree of formal competence), together with two main elaborate theoretical approaches (mental logic, mental models) specifically developed to explain performance on the artificial laboratory tasks. The new enquiry into ecologically valid deductive abilities started relatively recently. This chapter, which is essentially theoretical and programmatic, is devoted to this question. After summarizing the knowledge available to date, it considers the question of the kind of formalism that could inspire the modelling of human performance in this domain. Because so many researchers in the fields of judgement and decision making have chosen the probability calculus as a model, it is tempting for investigators of reasoning to follow suit. The chapter pays special attention to the concept of probability and examines its adequacy to represent people's uncertainty in the domain of reasoning. It argues that the probability calculus may not be any more appropriate than classical logic as a model. Finally, it considers a few alternative formalisms that are possible candidates for modelling reasoning with uncertain premises.