People suffering from severe monothematic delusions, such as Capgras, Fregoli, or Cotard patients, regularly assert extraordinary and unlikely things. For example, some say that their loved ones have been replaced by impostors. A popular view in philosophy and cognitive science is that such monothematic delusions aren't beliefs because they don't guide behaviour and affect in the way that beliefs do. Or, if they are beliefs, they are somehow anomalous, atypical, or marginal beliefs. We present evidence from five studies that folk (...) psychology unambiguously views monothematic delusions as stereotypical beliefs. This calls into question widespread assumptions in the professional literature about belief's stereotypical functional profile. We also show that folk psychology views delusional patients as holding contradictory beliefs. And we show that frequent assertion is a powerful cue to belief ascription, more powerful than even a robust and consistent track record of non-verbal behaviour. (shrink)

The central hypothesis of this book, Delusions and Beliefs: A Philosophical Inquiry (Routledge, 2019), is that delusions are malfunctional beliefs (Chapter 1); they belong to the category of belief (Chapter 2) but, unlike mundane false or irrational beliefs, they fail to perform some functions of belief (Chapter 3). More precisely, delusions directly or indirectly involve some malfunctioning cognitive mechanisms, which is empirically supported by the two-factor account of delusion formation (Chapter 4).

Despite the diagnostic relevance of thought insertion for disorders such as schizophrenia, the debates about its aetiology are far from resolved. This paper claims that in paying exclusive attention to the perceptual and cognitive impairments leading to delusional experiences in general, current deficit approaches overlook the role that affective disturbances might play in giving rise to cases of thought insertion. In the context of psychosis, affective impairments are often characterized as a consequence of the stress and anxiety caused by delusional (...) episodes. However, here I explore some of the conceptual and empirical reasons to think that affective problems might in fact play a crucial doxastic role in the aetiology of thought insertion. Finally, I conclude by proposing a way of integrating the main insights of my analysis with the current ‘two-factor’ deficit approach to thought insertion and I explore the potential adaptive role that some delusions might have within this framework. (shrink)

Delusions have traditionally been considered the hallmark of mental illness, and their conception, diagnosis and treatment raise many of the fundamental conceptual and practical questions of psychopathology. One of these fundamental questions is whether delusions are understandable. In this paper, we propose to consider the question of understandability of delusions from a philosophy of language perspective. For this purpose, we frame the question of how delusions can be understood as a question about the meaning of delusional utterances. Accordingly, we ask: (...) “what meaning(s) can delusional utterances possibly have?”. We argue that in the current literature, there is a standard approach to the meaning of delusional utterances, namely the descriptive account which assumes that a delusional utterance “p” means that p is the case. Drawing on Speech Act Theory, we argue that solely relying on the descriptive account disregards essential ways of how linguistic meaning is constituted. Further, we show that Speech Act Theory can prove a helpful addition to the theoretical and clinical “toolbox” used for attempting to understand delusional utterances. This, we believe, may address some of the theoretical and clinical shortcomings of using only the currently predominant descriptive account. (shrink)

I develop and defend the view that subjects are necessarily psychologically able to revise their beliefs in response to relevant counter-evidence. Specifically, subjects can revise their beliefs in response to relevant counter-evidence, given their current psychological mechanisms and skills. If a subject lacks this ability, then the mental state in question is not a belief, though it may be some other kind of cognitive attitude, such as a supposi-tion, an entertained thought, or a pretense. The result is a moderately revisionary (...) view of belief: while most mental states we thought were beliefs are beliefs, some mental states which we thought were beliefs are not beliefs. The argument for this view draws on two key claims: First, subjects are rationally obligated to revise their beliefs in response to relevant counter-evidence. Second, if some subject is rationally obligated to revise one of her mental states, then that subject can revise that mental state, given her current psychological mechanisms and skills. Along the way to defending these claims, I argue that rational obligations can govern activities which reflect on one’s rational character, whether or not those activities are under one’s voluntary control. I also show how the relevant version of epistemic ‘ought’ implies ‘can’ survives an objection which plagues other variants of the principle. (shrink)

Many of our beliefs behave irrationally: this is hardly news to anyone. Although beliefs’ irrational tendencies need to be taken into account, this paper argues that beliefs necessarily preserve at least a minimal level of rationality. This view offers a plausible picture of what makes belief unique and will help us to set beliefs apart from other cognitive attitudes.

Here I summarise the main arguments in Delusions and Other Irrational Beliefs [1]. The book addresses the question whether there is a rationality constraint on belief ascription and defends a doxastic account of clinical delusions.

Here I reply to the main points raised by the commentators on the arguments put forward in my Delusions and Other Irrational Beliefs (OUP, 2009). My response is aimed at defending a modest doxastic account of clinical delusions, and is articulated in three sections. First, I consider the view that delusions are inbetween perceptual and doxastic states, defended by Jacob Hohwy and Vivek Rajan, and the view that delusions are failed attempts at believing or not-quitebeliefs, proposed by Eric Schwitzgebel and (...) Maura Tumulty. Then, I address the relationship between the doxastic account of delusions and the role, nature, and prospects of folk psychology, which is discussed by Dominic Murphy, Keith Frankish, and Maura Tumulty in their contributions. In the final remarks, I turn to the continuity thesis and suggest that, although there are important differences between clinical delusions and non-pathological beliefs, these differences cannot be characterised satisfactorily in epistemic terms. (shrink)

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.

Clinically significant delusion is a symptom of a number of mental illnesses. We rely on what a person says and how she behaves in order to identify if she has this symptom and it is clear from the literature that delusions are heterogeneous and extremely difficult to define. People with active delusions were interviewed to explore what it is like to develop and experience delusion. The transcribed interview data was analysed to identify themes and narrative trajectories that help to explain (...) the phenomenon. Results showed that delusions can sometimes provide pragmatic benefits and that the genesis of some delusions can be characterised in terms of the enactivist notion of affective framing. Affective framing is a term that captures the background emotions that enable know-how in terms of goal directed action and cognition. If a person’s affective frame alters the world is no longer understood and know-how is lost. The way in which a person relates to her environment can be highly anomalous thus requiring her to find an extraordinary explanation. I argue that delusions arise as a result of a breakdown in affective framing and offer a conceptualisation of delusion supported by empirical findings. (shrink)

Background Delusions are a significant feature of mental illnesses and can occur in many clinical conditions (Maher, 2001) yet the standard clinical definition (American Psychiatric Association. DSM-5 Task Force, 2013) is highly contentious. Much of the literature holds elements such as bizarreness of content and incorrigibility of belief as defining factors of delusion. However, on closer inspection, delusions are not so easy to pin down. The difficulty in defining delusion is not a new one as “…we are all capable of (...) having convictions and it is a universal human characteristic to hold on to our own mistaken judgements.” (Jaspers, 1963, p.63). Objective I intend to highlight some of the difficulties associated with the definition of delusion and perhaps clarify the phenomenology. Methodology I examine some of the philosophical, psychological and psychiatric literature with regard to the definition of delusion. I also consider my experience of my own mental activity and experiences from my therapeutic work. Results/Conclusion I identify that delusions are a heterogeneous group and that there may be more than one ‘class’ of delusion. I also show that delusions are multi-dimensional with characteristics on a continuum with normal beliefs and that further research is needed to clarify the phenomenology. (shrink)