Are people rational? This question was central to Greek thought; and has been at the heart of psychology and philosophy for millennia. This book provides a radical and controversial reappraisal of conventional wisdom in the psychology of reasoning, proposing that the Western conception of themind as a logical system is flawed at the very outset. It argues that cognition should be understood in terms of probability theory, the calculus of uncertain reasoning, rather than in terms of logic, the calculus of certain reasoning.

Mike Oaksford is Professor of Psychology and Head of School at Birkbeck College London. He was a research fellow at the Centre for Cognitive Science, University of Edinburgh, he was then lecturer at the University of Wales, Bangor, and senior lecturer at the University of Warwick, before moving to Cardiff University in 1996 as Professor of Experimental Psychology, a post he held until 2005. His research interests are in the area of human reasoning and decision making. In particular, with his colleague Nick Chater, he has been developing a Bayesian probabilistic approach to deductive reasoning tasks. According to this approach reasoning "biases" are the result of applying the wrong normative model and failing to take account of people's normal environment. He also studies the way the emotions affect and interact with reasoning and decision making processes.
Nick Chater is Professor of Cognitive and Decision Sciences at University College London. He has an M.A. in Psychology from Cambridge University, and a PhD in Cognitive Science from Edinburgh. He has held academic appointments at Edinburgh, Oxford, and Warwick Universities. His research focussed on attempting to find general principles that may be applicable across many cognitive domains, ranging from reasoning and decision making, to language acquisition and processing, to perception and categorization. Since the late 1980s, in collaboration with Mike Oaksford, he has been interested in the application of probabilistic and information-theoretic methods for understanding human reasoning.