The Philosophy and Psychology of Delusions

Routledge, 2023

This book presents new philosophical work on delusions and their impact on everyday human behavior. It explores a cluster of related topics at the intersection of philosophy of mind and psychiatry, while also charting the historical development of work on delusions.

Philosophy Compass, 2015

In this paper we review two debates in the current literature on clinical delusions. One debate is about what delusions are. If delusions are beliefs, why are they described as failing to play the causal roles that characterise beliefs, such as being responsive to evidence and guiding action? The other debate is about how delusions develop. What processes lead people to form delusions and maintain them in the face of challenges and counter-evidence? Do the formation and maintenance of delusions require abnormal experience alone, or also reasoning biases or deficits? We hope to show that the focus on delusions has made a substantial contribution to the philosophy of the mind and continues to raise issues that are central to defining the concept of belief and gaining a better understanding of how people process information and learn about the world.

AVANT. The Journal of the Philosophical-Interdisciplinary Vanguard, 2014

The aim of the article is to present the contemporary concepts of delusions from the phenomenological perspective. The difficulties to define delusions and the examples of delusional disorders, such as delusional mood, Cotard's syndrome, or Capgras delusions, serve as the point of departure for this analysis. The questions of the phenomenological understanding of delusions are presented in the context of Karl Jaspers' theory of the incomprehensibility of psychotic thinking (primary delusions, delusional mood). The subsequent analysis presents the constraints of contemporary cognitive theories of delusions. The criticism of said theories highlights the need for creating a broader concept of experience and cognition and results in the proposition to use the terms "background" and "embodiment" as theoretical tools for a more complete understanding of the peculiarities of delusional experience.

Delusions in Context, 2018

This open access book offers an exploration of delusions—unusual beliefs that can significantly disrupt people’s lives. Experts from a range of disciplinary backgrounds, including lived experience, clinical psychiatry, philosophy, clinical psychology, and cognitive neuroscience, discuss how delusions emerge, why it is so difficult to give them up, what their effects are, how they are managed, and what we can do to reduce the stigma associated with them. Taken as a whole, the book proposes that there is continuity between delusions and everyday beliefs. It is essential reading for researchers working on delusions and mental health more generally, and will also appeal to anybody who wants to gain a better understanding of what happens when the way we experience and interpret the world is different from that of the people around us.

British Journal of Clinical Psychology, 1999

To review critically the evidence for three contemporary theories of delusions.

Oxford Handbook of Philosophy of Psychiatry, 2013

In this chapter, we discuss a treatment of delusions from a phenomenological perspective, which focuses on the variety of ways in which one might experience delusions and the delusional world. In contrast to standard psychiatric definitions of delusion as a false belief due to poor reality-testing, we suggest that delusions may be more fully understood as a transformation in the horizons or possibilities for experience. The early phenomenological psychiatrist Karl Jaspers suggested that the defining feature of schizophrenic or “true” delusions is their un-understandability, referring to the lack of apparent explanation for the degree of conviction or the experiential alterations attached to these bizarre delusions. In spite of this difficulty, however, we attempt to render the delusional experience comprehensible by exploring the origins and varieties of delusional transformations of self and world. In so doing, we examine the changes in inner and outer experience that occur in the delusional mood preceding the formation of a delusion, and how a delusion might develop out of these experiences; the transformations of reality that can create a kind of double-bookkeeping or double exposure, where both delusions and standard reality are felt to be simultaneously real and unreal; and the qualities of delusions that arise in paranoid, affective, and monothematic organic conditions. Thus, we attempt to move beyond standard conceptions of delusions as un-understandable or due to disturbed reality-testing, to show how an appreciation for the varieties of delusional experience permits a greater degree of empathic understanding.

Mind and Language, 2000

After reviewing factors implicated in the generation of delusional beliefs, we conclude that whilst a perceptual aberration coupled with a particular type of attributional bias may be necessary to explain the specific thematic content of a bizarre delusion, neither of these factors, whether in isolation or in combination, is sufficient to explain the presence of delusional beliefs. In contrast to bias models (theories which explain delusion formation in terms of extremes of normal reasoning biases), we advocate a deficit model of delusion formation-that is, delusions arise when the normal cognitive system which people use to generate, evaluate, and then adopt beliefs is damaged. Mere bias we think inadequate to explain bizarre delusions which defy commonsense and persist despite overwhelming rational counter-argument. In particular, we propose that two deficits must be present in the normal cognitive system to explain bizarre delusions: (1) there must be some damage to sensory and/or attentional-orienting mechanisms which causes an aberrant perception-this explains the bizarre content of the causal hypothesis generated to explain what is happening; and (2) there must also be a failure of normal belief evaluation-this explains why a hypothesis, implausible in the light of general commonsense, is adopted as belief. This latter deficit occurs, we suggest, when an individual is incapable of suspending the natural favoured status of direct first-person evidence in order to critically evaluate hypotheses, given equal priority whether based on direct or indirect sources of information. In contrast, delusions with 'ordinary' content may arise when a single deficit of normal belief evaluation occurs in the context of an extreme (but normal) attentional bias, thus causing failure to critically evaluate hypotheses based on misperceptions and misintrepretations of ambiguous (but ordinary) first-person experience.

There is continuing debate about the nature of delusions and whether they are properly described as beliefs. This chapter argues that in order to make progress on this issue we need to adopt a more complex taxonomy of psychological states and processes, building on recent work in philosophy of psychology and cognitive science. I distinguish two levels of belief, and argue that delusions, if they are beliefs at all, belong to the second of them. I go on to offer an account of second-level belief according to which it is a species of a broader mental type, sometimes called ‘acceptance’, which is dependent on attitudes at the first level. I then propose that delusions are acceptances, some of which fall within, and some without, the narrower class of second-level beliefs. I argue that this view explains our competing intuitions about delusions and that it has important implications for understanding deluded patients.

The aim of the paper is to offer a characterisation of delusional systems of belief. The view defended in the paper is that the explanations that appear in delusional systems of belief do not effect a reduction in the number of things left unexplained. In this respect, it is argued, delusions differ from both common sense and from scientific explanations. The thesis is defended with a range of examples, including some simple examples from the history of science. Particular attention is paid to differences between scientific explanations and those that figure in delusions. Since delusions leave more things unexplained than common-sense and science, it follows that a person suffering from delusional belief has a reduced level of understanding of the world around them. It is also argued that that the thesis that delusional beliefs fail to minimise that which requires explanation is able to deal with some usually “difficult cases” for accounts of delusional thinking.

2017

The present thesis surveys different philosophical approaches to the nature of delusions: specifically, their ontology. However, since none of the various theories of the nature of delusions succeeds, I argue that there must be something problematic about the form of the analyses commonly offered. My general conclusion is that one cannot characterize delusions without taking away what it is distinctive about them.