Lisa Bortolotti

In this chapter, our focus is the role played by notions of rationality in the diagnosis of mental disorders, and in the practice of overriding patient autonomy in psychiatry. We describe and evaluate different hypotheses concerning the relationship between rationality and diagnosis, raising questions about what features underpin psychiatric categories. These questions reinforce widely held concerns about the use of diagnosis as a justification for overriding autonomy, which have motivated a shift to mental incapacity as an alternative justification. However, this approach too has recently been criticized from a mental disability rights perspective. Our analysis of the relationship between mental capacity and rationality is used to illuminate these concerns, and to investigate further the relationship between rationality and psychiatric diagnosis.

We talk about irrationality when behaviour defies explanation or prediction, when decisions are driven by emotions or instinct rather than by reflection, when reasoning fails to conform to basic principles of logic and probability, and when beliefs lack coherence or empirical support. Depending on the context, agents exhibiting irrational behaviour may be described as foolish, ignorant, unwise or even insane. In this clear and engaging introduction to current debates on irrationality, Lisa Bortolotti presents the many facets of the concept and offers an original account of the importance of judgements of irrationality as value judgements. The book examines the standards against which we measure human behaviour, and reviews the often serious implications of judgements of irrationality for ethics and policy. Bortolotti argues that we should adopt a more critical stance towards accepted standards of rationality in the light of the often surprising outcomes of philosophical inquiry and cognitive science research into decision making. Irrationality is an accessible guide to the concept and will be essential reading for students and scholars interested in the limitations of human cognition and human agency.

Does conscious reflection lead to good decision-making? Whereas engaging in reflection is traditionally thought to be the best way to make wise choices, recent psychological evidence undermines the role of reflection in lay and expert judgement. The literature suggests that thinking about reasons does not improve the choices people make, and that experts do not engage in reflection, but base their judgements on intuition, often shaped by extensive previous experience. Can we square the traditional accounts of wisdom with the results of these empirical studies? Should we even attempt to? I shall defend the view that philosophy and cognitive sciences genuinely interact in tackling questions such as whether reflection leads to making wise choices.