Delusions and Other Irrational Beliefs

Delusional people are people saying very bizarre things like they are dead, their spouse is a robot, the TV star is talking to them, they are possessed by the devil, aliens are following them, and so on. Even though we know that they are not identical, terms like “delusion” and “mental illness” are often used as synonyms in ordinary language. This comes from what psychopathology tradition handed down: delusion is the key psychopathological phenomenon, although essentially un-understandable (Jaspers, 1959). In her book Delusion and Other Irrational Beliefs, Lisa Bortolotti explores the topic of delusion from the epistemological perspective of analytical philosophy. Do delusional people really believe what they say? This question is as interesting as it is pressing for clinics. From the very beginning however this work is engaged in defending two core ideas. First, understanding belief, regardless of whether it is a “real pattern” or not (Dennett, 1991), is relevant to understanding what delusions are. Second, delusions can be beliefs like others. This is only a small part of what makes this book a fascinating and indispensable work. The aim of the book is arguing against accounts which deny the doxastic nature of delusion. In philosophy of mind, the claim that delusions are not beliefs is taken as a modus tollens argument deriving from the general premise that all beliefs presuppose a background rationality, as assumed by belief attribution theory in the Davidson-Dennett tradition. In other words, since delusions do not meet the rationality constraint (since they are irrational phenomena), they are not beliefs at all. Chapter 1 is an opening background section devoted both to the rationality constraint in belief attribution theory and to conceptions and taxonomy of