Reasoning and rationality

Dualities abound in the contemporary study of reasoning, and it is striking how this kind of theoretical structure has characterized so much of recent research. For instance, we have the dual-process theory of thought, which began with Evans and Wason in the 1970s (Evans & Wason, 1976; Wason & Evans, 1975) and has cropped up in similar forms in a number of different and independent fields in rough synchrony (see Evans, chapter 10 this volume; Evans & Over, 1996; Stanovich, 1999). Then there is dual rationality theory, in which there is a broad divide between rationality conceived as adherence to (or justification by) an appropriate normative system, and rationality as doing the right thing in the circumstances, i.e., as optimal goal attainment. Evans and Over (1996) and Stanovich (1999; Stanovich & West, 2000) again provide extensive surveys of this second duality.