This thesis develops a novel framework for explaining delusions. In Chapter 1, I introduce the two fundamental challenges posed by delusions: the evidence challenge lies in explaining the flagrant ways delusions flout evidence; and the specificity challenge lies in explaining the fact that patients’ delusions are often about a few specific themes, and patients rarely have a wide range of delusional or odd beliefs. In Chapter 2, I discuss the strengths and weaknesses of current theories of delusions, which typically appeal (...) to one or both of two factors: anomalous experience and reasoning abnormality. I argue that anomalous experience can help explain the specificity of delusions, but has difficulties in addressing the evidence challenge; reasoning abnormality can help address the evidence challenge, but has difficulties in explaining the specificity of delusions. This suggests that there may be an important factor that has not been captured by current theories of delusions. To search for this missing factor, in Chapter 3, I turn to normal believing. Inspired by the literature on Cartesian clarity and phenomenal dogmatism, I develop a dual-force framework of believing, according to which beliefs can be understood as the results of the interaction between the justificatory force and causal force of evidence and the justificatory force and causal force of clear experience, in which something clearly seems to be so to the subject. This framework suggests that the missing factor may be the clear experience with its distinctive phenomenal clarity that compels assent. In Chapter 4, I return to delusions, and argue that the dualforce framework can help us to get a better grip on some personal descriptions of delusions; make progress in addressing the evidence and specificity challenges of delusions; and shed new light on the underpinnings of delusions. In the end, I conclude with some remaining questions for future study. (shrink)

From an evolutionary standpoint, a default presumption is that true beliefs are adaptive and misbeliefs maladaptive. But if humans are biologically engineered to appraise the world accurately and to form true beliefs, how are we to explain the routine exceptions to this rule? How can we account for mistaken beliefs, bizarre delusions, and instances of self-deception? We explore this question in some detail. We begin by articulating a distinction between two general types of misbelief: those resulting from a breakdown in (...) the normal functioning of the belief formation system (e.g., delusions) and those arising in the normal course of that system's operations (e.g., beliefs based on incomplete or inaccurate information). The former are instances of biological dysfunction or pathology, reflecting “culpable” limitations of evolutionary design. Although the latter category includes undesirable (but tolerable) by-products of “forgivably” limited design, our quarry is a contentious subclass of this category: misbeliefs best conceived as design features. Such misbeliefs, unlike occasional lucky falsehoods, would have been systematically adaptive in the evolutionary past. Such misbeliefs, furthermore, would not be reducible to judicious – but doxastically1noncommittal – action policies. Finally, such misbeliefs would have been adaptive in themselves, constituting more than mere by-products of adaptively biased misbelief-producing systems. We explore a range of potential candidates for evolved misbelief, and conclude that, of those surveyed, onlypositive illusionsmeet our criteria. (shrink)

Anorexia nervosa involves seemingly irrational beliefs about body size and the value of thinness. Historically, researchers and clinicians have avoided referring to such beliefs as delusions, instead opting for the label ‘overvalued ideas’. I discuss the relationship between the beliefs associated with anorexia nervosa and the distinction between delusions and overvalued ideas, as it is conceived in both European and American psychiatric traditions. In doing so, I question the benefit of applying the concepts of delusion and overvalued idea to anorexia (...) nervosa and raise some issues with contemporary use of the Brown Assessment of Beliefs scale for assessing the level of delusionality associated with the disorder. (shrink)

: The notion of a delusion occupies a central place in psychotherapy. The presence of delusional thinking in a patient is often regarded as indicative of psychosis. And yet, the nature of a delusion is still widely disputed. The difficulty of defining a delusion has proved so difficult that some prominent authors have declared the task impossible. The aim of this paper is to offer a characterisation of delusional systems of thought. In this paper is argued that delusions, unlike scientific (...) explanations and the explanations generally offered by common sense, fail to minimise that which requires explanation. In the first part of the paper, difficulties with extant accounts will be discussed. In the following parts, the author’s own account of delusional thoughts will be developed and some difficult cases considered. It will be argued that delusions differ from more typical beliefs in the number of things that they leave unexplained. Delusions, unlike those beliefs we typically see as rational, bring about an increase in the number of things requiring explanation. Keywords: Delusions; Epistemology; Analysis; Explanation; Rationality Aspetti epistemologici del pensiero delirante Riassunto: La nozione di delirio occupa una posizione centrale nell’ambito della psicoterapia. La presenza del pensiero delirante in un paziente è considerata spesso come un indice di psicosi. E, tuttavia, la natura del delirio non è ancora oggetto di ampio accordo tra gli studiosi. La difficoltà nel definire il delirio si è mostrata talmente ostica che diversi importanti studiosi hanno dichiarato questo compito impossibile. Lo scopo di questo lavoro è quello di offrire una caratterizzazione dei sistemi di pensiero delirante. Si sosterrà che i deliri, diversamente dalle spiegazioni scientifiche e da quelle offerte generalmente dal senso comune, non riescono a ridurre quanto necessita di una spiegazione. Nella prima parte del lavoro, saranno discusse le difficoltà degli approcci correnti. Nelle parti seguenti verrà proposto l’approccio dell’autore ai pensieri deliranti e verranno presi in esame alcuni casi complessi. Si sosterrà che i deliri si distinguono dai casi più tipici di credenza per il numero di cose che lasciano senza spiegazione. I deliri, diversamente dalle credenze che tipicamente consideriamo irrazionali, determinano un incremento del numero di cose che richiedono una spiegazione. Parole chiave: Delirio; Epistemologia; Analisi; Spiegazione; Razionalità. (shrink)

The impact of our desires and preferences upon our ordinary, everyday beliefs is well-documented [Gilovich, T. . How we know what isn’t so: The fallibility of human reason in everyday life. New York: The Free Press.]. The influence of such motivational factors on delusions, which are instances of pathological misbelief, has tended however to be neglected by certain prevailing models of delusion formation and maintenance. This paper explores a distinction between two general classes of theoretical explanation for delusions; the motivational (...) and the deficit. Motivational approaches view delusions as extreme instances of self-deception; as defensive attempts to relieve pain and distress. Deficit approaches, in contrast, view delusions as the consequence of defects in the normal functioning of belief mechanisms, underpinned by neuroanatomical or neurophysiological abnormalities. It is argued that although there are good reasons to be sceptical of motivational theories , recent experiments confirm that motives are important causal forces where delusions are concerned. It is therefore concluded that the most comprehensive account of delusions will involve a theoretical unification of both motivational and deficit approaches. (shrink)

This paper explores the phenomenology of the Capgras and Cotard delusions. The former is generally characterised as the belief that relatives or friends have been replaced by impostors, and the latter as the conviction that one is dead or has ceased to exist. A commonly reported feature of these delusions is an experienced ''defamiliarisation'' or even ''derealisation'' of things, which is associated with an absence or distortion of affect. I suggest that the importance attributed to affect by current explanations of (...) delusional experience can serve to make explicit the manner in which we ordinarily experience the world under a taken-for-granted aspect of affective familiarity. This implicit feeling is, I argue, partly constitutive of our sense of reality. However, so-called ''folk psychology,'' which is generally adopted by philosophers as an initial interpretive backdrop for delusional beliefs and for beliefs more generally, fails to accommodate it. As a consequence, some pervasive philosophical assumptions concerning the manner in which we experience and understand the world, ourselves, and each other are called into question. (shrink)

With the waves of reform occurring in mental health legislation in England and other jurisdictions, mental capacity is set to become a key medico-legal concept. The concept is central to the law of informed consent and is closely aligned to the philosophical concept of autonomy. It is also closely related to mental disorder. This paper explores the interdisciplinary terrain where mental capacity is located. Our aim is to identify core dilemmas and to suggest pathways for future interdisciplinary research. The terrain (...) can be separated into three types of discussion: philosophical, legal and psychiatric. Each discussion approaches mental capacity and judgmental autonomy from a different perspective yet each discussion struggles over two key dilemmas: whether mental capacity and autonomy is/should be a moral or a psychological notion and whether rationality is the key constitutive factor. We suggest that further theoretical work will have to be interdisciplinary and that this work offers an opportunity for the law to enrich its interpretation of mental capacity, for psychiatry to clarify the normative elements latent in its concepts and for philosophy to advance understanding of autonomy through the study of decisional dysfunction. The new pressures on medical and legal practice to be more explicit about mental capacity make this work a priority. (shrink)

This work sets out to present how the notion of delusion may be understood (and extended) within the semantic framework of Robert Brandom's inferentialism. The mechanisms of reliability and community‐oriented proprieties, among others, provide inferentialists with effective tools for understanding commitments (and so beliefs) in communities. These tools may be used to describe and assess both commitments that we might consider sound and commitments that we might consider delusional, both in terms of how they arise and in terms of how (...) they may be reinforced. Delusions are accordingly rendered in perspectival and normative terms, which is elaborated through a number of examples. The picture of how a delusional commitment may be understood, how it may be reinforced, and its character as community internal or external provide some interesting perspectives on delusions in shared social contexts, as well as how they may originate intractable conflicts and disconnects between sub‐groups within a broader linguistic community. (shrink)

In their pursuit of adaptively biased misbelief-making systems, McKay & Dennett (M&D) describe a putative doxastic shear-pin system which enables misbeliefs to form in situations of extreme psychological stress. Rather than discussing their argument, I consider how this shear-pin system might combine with both pathological belief-making ( breakdowns caused by neuropathy) and normal belief-making to explain a spectrum of delusions.

We propose another positive illusion that fits with McKay & Dennett's (M&D's) criteria for adaptive misbeliefs. This illusion is pervasive in adult reasoning but we focus on its prevalence in children's developing theories. It is a strongly held conviction arising from normal functioning of the doxastic system that confers adaptive advantage on the individual.

Naive physics beliefs can be systematically mistaken. They provide a useful test-bed because they are common, and also because their existence must rely on some adaptive advantage, within a given context. In the second part of the commentary we also ask questions about when a whole family of misbeliefs should be considered together as a single phenomenon.

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)

This dissertation seeks to examine the validity of the justification commonly offered for a coercive (1) psychiatric intervention, namely that the intervention was in the ‘best interests’ of the subject and/or that the subject posed a danger to others. As a first step,it was decided to analyse justifications based on ‘best interests’ [the ‘Stage 1’ argument] separately from those based on dangerousness [the ‘Stage 2’ argument]. Justifications based on both were the focus of the ‘Stage 3’ argument. Legal and philosophical (...) analyses of coercive psychiatric interventions generally regard such interventions as embodying a benign paternalism occasioning slight, if any, ethical concern. Whilst there are some dissenting voices even at the very heart of academic and professional psychiatry, the majority of psychiatrists also appear to share such views. The aim of this dissertation is to show that such a perspective is mistaken and that such interventions raise philosophical and ethical questions of the profoundest importance.(2) The philosophical well-spring of the Stage 1 dissertation argument lay in an observation made by Philippa Foot (3) that the “… right to be let free from unwanted interference” is one of the most fundamental and distinctive rights of persons, a right which takes precedence over any “… action we would dearly like to take for his sake.” This – in conjunction with the recognition that some coercive psychiatric interventions are of a gravity as to result in the personhood of the subject being severely damaged if not destroyed – suggested that the concept of personhood play a central role in the formulation of the dissertation argument. For ease of analysis it was presumed that the term ‘person’ could be defined by a set of necessary and sufficient conditions of which ‘minimum levels of rationality’ and ‘ability to communicate’ were the only conditions relevant to the formulation of justifications for coercive psychiatric interventions. This presumption was explicated into a number of postulates which enabled the construction of a rigorous foundation on which to develop the dissertation argument. This argument then sought to determine whether psychiatric assessments of irrationality were accurate and reliable. In furtherance of this analysis it was necessary to examine the reliability of psychiatric determinations in other areas of claimed expertise namely diagnosis, treatment and assessment of dangerousness. This ‘crossing of the disciplinary threshold’ brought to light the dearth of studies on psychiatric misdiagnosis and iatrogenic harm. A variant of the Precautionary Principle was developed to enable the extent of such harms to be estimated. The not insignificant levels of psychiatric misdiagnosis and iatrogenic harm and erroneous assessments of dangerousness which were thus found are of considerable relevance to any ethical analysis of the justification for coercive psychiatric intervention and serve to undermine simple paternalistic justifications. --- (1)The term ‘coercive’ (rather than ‘non-consensual’) is used to indicate an intervention carried out against the explicit and contemporaneous objections of the subject (2)Not least because the number of individuals detained in Irish psychiatric hospitals is of a comparable order of magnitude to the number detained in Irish prisons subsequent to a criminal conviction (3)See Foot (1977), p.102. (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)