Delusions

Delusions are standardly defined as attitudes that are not amenable to change in light of conflicting evidence. But what evidence do people with delusion have for and against it? Do delusions really go against their total evidence? How are the answers affected by different conceptions of evidence? -/- This chapter focuses on how delusions relate to evidence. I consider what delusions-relevant evidence people with delusions have. I give some reasons to think that people typically have evidence for their delusions, and (...) that the evidence they have against them is often overstated. I draw on this discussion to consider whether delusions are evidentially supported and epistemically rational. Finally, I discuss implications for the nature of delusion, responsibility, and treatment and suggest directions for future research. Throughout, the discussion is sensitive to different conceptions of evidence and rationality in epistemology. -/- A central upshot is that what we should say about the epistemic standing of delusions depends substantively on our positions in epistemology, in particular, on the debate between internalists and externalists about evidence. If we want clarity on the epistemic standing of delusions, we need to incorporate more sophisticated tools from epistemology. (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)

Popular two-factor accounts of thought insertion hold that this symptom of psychosis is caused by two elements working in tandem: an anomalous experience of some kind (the first factor) and a reasoning deficit or bias (the second factor). This chapter develops a very different alternative to explaining and treating thought insertion—one that views thought insertion as a form persecutory delusion. If this thesis is correct, clinical interventions for persecutory delusions may be successful for thought insertion as well. The chapter begins (...) by presenting several difficulties for two-factor accounts of thought insertion and for two-factor accounts of delusions more generally. It then discusses positive reasons for seeing thought insertion as a form of persecutory delusion. The positive case begins with reflection on first-person descriptions of thought insertion gleaned from online discussion forums. It continues by considering ways in which clinical diagnostic tools may create the appearance of deep differences between symptoms such as thought insertion and persecutory delusions where there are none. This case is bolstered by evidence for considerable variability in the content of delusions patients present with over time. Implications for the treatment of thought insertion are then considered. (shrink)

The cognitive science of belief is a burgeoning field, with insights ranging from detailing the fundamental structure of the mind, to explaining the spread of fake news. Here we highlight how new insights into belief acquisition, storage, and change can transform our understanding of psychiatric disorders. Although we focus on monothematic delusions, the conclusions apply more broadly. -/- .

This chapter aims to get away from the ‘psychological attitude’ approach framing current philosophical discussion of delusion. We ask not what kind of attitude a delusion is – a belief or an imagination? Something else? – as if it were already clear what the ‘content’ of a delusion could be. We aim instead to shift attention to the question of the ‘object’ of delusions. What is delusion of? What is the object of this form of thinking? This focus on a (...) delusion’s object, over its attitudinal nature, is partly motivated by a desire properly to connect delusory thought with ordinary forms of fantastical thinking that are ubiquitous in the experiences faced by reflective humans in everyday life. We aim at securing a continuity, in a way that much extant discussion of delusion fails to, between delusory thought with more ordinary forms of thinking present in, for example, fantastical or magical thinking. Exploring familiar expressions of such thinking, especially those involved in love and loss, enables us to bring out the way in which such expressions convey forms of affective self-consciousness – that have the subject and her relations as an object – that are not naturally taken as reports liable to investigation as true or false. This raises the question about what how to think about what someone is doing when they give expression to a delusion should we think of them as expressing an attitude towards a truth or false content, or may they be doing something rather different? (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)

How many factors, i.e. departures from normality, are necessary to explain a delusion? Maher’s classic one-factor theory argues that the only factor is the patient’s anomalous experience, and a delusion arises as a normal explanation of this experience. The more recent two-factor theory, on the other hand, contends that a second factor is also needed, with reasoning abnormality being a potential candidate, and a delusion arises as an abnormal explanation of the anomalous experience. In the past few years, although there (...) has been an increasing number of scholars offering a variety of arguments in defence of Maher’s one-factor theory, these arguments have not been adequately addressed by two-factor theorists. This paper aims to address this gap by critically examining the arguments on three crucial issues: the intelligibility of delusions, the dissociation between anomalous experiences and delusions, and the empirical evidence of a second factor. I will argue that the Maherian notion of anomalous experience is not sufficient for explaining delusions and the two-factor theory is on the right track in its search for the missing factor in the aetiology of delusions. (shrink)

The DSM‐5 highlights two essential psychological features of anorexia nervosa (AN): recalcitrant fear of gaining weight and body image disturbance. Prominent accounts grant false beliefs about body weight and shape a central role in the explanation of AN behavior. In this article, we propose a stronger emphasis on recalcitrant fear. We show that such fear can explain AN behavior without the intermediary of a false belief, and thus without the associated explanatory burdens and conceptual difficulties. We illustrate how shifting the (...) emphasis from false belief to recalcitrant fear can supplement a number of different non‐doxastic models of AN. (shrink)

In Delusions and Beliefs, Kengo Miyazono proposes an extended and convincing argument for the thesis that delusions are malfunctional beliefs. One of the key assumptions for this argument is that belief is a biological notion, and that the function of beliefs is a product of evolution. I challenge the thesis that evolutionary accounts can furnish an epistemologically satisfying account of beliefs because evolutionary success does not necessarily track epistemic success. Consequently, also delusions as beliefs cannot be explained in a satisfactory (...) manner by looking at beliefs’ evolutionary function. How can we then salvage the notion of delusions as epistemologically relevant malfunctioning beliefs? I propose that knowledge-first epistemology gives us a way out. Knowledge-first accounts argue that knowledge is more primitive than belief. That is, knowledge is not a kind of successful beliefs ; instead, beliefs are failed attempts at knowledge. Being a belief derives from the norms of knowledge. Explaining the epistemology of beliefs through the primitive norms of knowledge, we can also explain why delusions are malfunctional beliefs: The cognitive and psychological defects that produce delusions block the beliefs from becoming knowledge. Consequently, delusions are attempts at knowledge that have failed particularly badly. (shrink)

According to the Rationality Constraint, our concept of belief imposes limits on how much irrationality is compatible with having beliefs at all. We argue that empirical evidence of human irrationality from the psychology of reasoning and the psychopathology of delusion undermines only the most demanding versions of the Rationality Constraint, which require perfect rationality as a condition for having beliefs. The empirical evidence poses no threat to more relaxed versions of the Rationality Constraint, which only require only minimal rationality. Nevertheless, (...) we raise problems for all versions of the Rationality Constraint by appealing to more extreme forms of irrationality that are continuous with actual cases of human irrationality. In particular, we argue that there are conceivable cases of “mad belief” in which populations of Lewisian madmen have beliefs that are not even minimally rational. This undermines Lewis’s claim that our ordinary concept of belief is a theoretical concept that is implicitly defined by its role in folk psychology. We argue that introspection gives us a phenomenal concept of belief that cannot be analyzed by applying Lewis’s semantics for theoretical terms. (shrink)

This article describes a case of a teenager with early complex trauma due to chronic domestic violence. Cannabis use triggered auditory hallucinations, after which the teenager was diagnosed with an acute schizophrenia-like psychotic disorder. Antipsychotic medication did not fully resolve symptoms. Eventually the teenager chose to self-medicate with LSD in order to resolve a suicidal condition. The teenager carried out six unsupervised LSD sessions, followed by an extended period of almost daily use of inhaled low-dose DMT. Psychotic symptoms were mostly (...) resolved after approximately one year. Subsequent cannabis use caused a transient relapse. -/- While his psychosis may have been due to cannabis use in the presence of a genetic predisposition, LSD and DMT did not promote psychotic symptoms in this case, and resolved the suicidal condition in one session. Additional high-dose LSD sessions and low-dose DMT sessions appeared to resolve the symptoms related to the early complex trauma. Alternatively, if psychosis is understood as a massive defense system resulting from early complex trauma, and if his psychotic symptoms were partially due to such trauma, psychedelics appeared to transcend this defense system, providing access to traumatic memories in order to allow for an integrative treatment effect. -/- Information was acquired from medical record excerpts provided by the patient, a semi-structured retrospective video interview, and follow-up interviews a year later. The present case suggests a need for further studies on the relationship between psychedelics and psychotic disorders, the feasibility of supervised vs unsupervised settings for various situations, and alternative therapeutic models for utilizing the hyperaware-hypersensitive state induced by psychedelics. With regard to self-treatment, a harm reduction approach should be adopted. Low-risk psycholytic self-treatment protocols could be developed for future use in public health care systems. (shrink)

Delusions are deeply evidence-resistant. Patients with delusions are unmoved by evidence that is in direct conflict with the delusion, often responding to such evidence by offering obvious, and strange, confabulations. As a consequence, the standard view is that delusions are not evidence-responsive. This claim has been used as a key argumentative wedge in debates on the nature of delusions. Some have taken delusions to be beliefs and argued that this implies that belief is not constitutively evidence-responsive. Others hold fixed the (...) evidenceresponsiveness of belief and take this to show that delusions cannot be beliefs. Against this common assumption, I appeal to a large range of empirical evidence to argue that delusions are evidence-responsive in the sense that subjects have the capacity to respond to evidence on their delusion in rationally permissible ways. The extreme evidence-resistance of delusions is a consequence of powerful masking factors on these capacities, such as strange perceptual experiences, motivational factors, and cognitive biases. This view makes room for holding both that belief is constitutively evidence-responsive and that delusions are beliefs, and it has important implications for the study and treatment of delusions. (shrink)

Various psychopathologies of self-awareness, such as somatoparaphrenia and thought insertion in schizophrenia, might seem to threaten the viability of the higher-order thought (HOT) theory of consciousness since it requires a HOT about one’s own mental state to accompany every conscious state. The HOT theory of consciousness says that what makes a mental state a conscious mental state is that there is a HOT to the effect that “I am in mental state M” (Rosenthal 2005, Gennaro 2012). In a previous publication (...) (Gennaro 2015), I argued that a HOT theorist can adequately respond to this concern with respect to somatoparaphrenia. Somatoparaphrenia is a “depersonalization disorder” which is characterized by the sense of alienation from parts of one’s body. It is a bizarre type of body delusion where one denies ownership of a limb or an entire side of one’s body. My focus in the chapter, however, is on “inserted thoughts” which is a common symptom of schizophrenia, although it will also be useful to contrast it with somatoparaphrenia. Schizophrenia is a mental disorder which most commonly manifests itself through auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking. Thought insertion is the delusion that some thoughts are not “one’s own” in some sense or are somehow being inserted into one’s mind by someone else. Graham and Stephens (2000), for example, have suggested that thought insertion should be understood as alienated self-consciousness or meta-representation. I argue that HOT theory has nothing to fear from this phenomenon either and can consistently explain what happens in this admittedly unusual case. (shrink)

Delusions are unhinged hinge certainties. Delusions are defined as strongly anchored beliefs that do not change in the face of adverse evidence. The same goes for Wittgensteinian certainties. My paper refines the so-called framework views of delusion, presenting an argument that epistemically speaking, considering them to be certainties best accounts for delusions’ doxastic profile. Until now there has been little argument in favour of this position and the original proposals made too extreme predictions about the belief systems of delusional patients. (...) I show that my account fares better with the diverse objections that have been raised against older framework views of delusion (Campbell 2001, Gipps and Rhodes 2008). Finally, I examine what makes a harmless hinge into a pathological delusion. (shrink)

Among psychiatric conditions, delusions have received significant attention in the philosophical literature. This is partly due to the fact that many delusions are bizarre, and their contents interesting in and of themselves. But the disproportionate attention is also due to the notion that by studying what happens when perception, cognition, and belief go wrong, we can better understand what happens when these go right. In this paper, I attend to delusions for the second reason—by evaluating the epistemology of delusions, we (...) can better understand the epistemology of ordinary belief. More specifically, given recent advancements in our understanding of how delusions are formed, the epistemology of delusions motivates a proper functionalist account of the justification of belief. Proper functionalist accounts of the justification of belief hold that whether a belief is justified is partly determined by whether the system that produces the belief is functioning properly. Whatever pathology is responsible for delusion formation, restoring it to its proper function resolves the epistemic condition, an effect which motivates proper functionalism. (shrink)

Various psychopathologies of self-awareness, such as somatoparaphrenia and thought insertion in schizophrenia, might seem to threaten the viability of the higher-order thought (HOT) theory of consciousness since it requires a HOT about one’s own mental state to accompany every conscious state. The HOT theory of consciousness says that what makes a mental state a conscious mental state is that there is a HOT to the effect that “I am in mental state M.” I have argued in previous work that a (...) HOT theorist can adequately respond to this concern with respect to somatoparaphrenia and thought insertion. There is also Cotard syndrome which is a rare neuropsychiatric disorder in which people hold the delusional belief that they are dead, do not exist, or have lost their blood or internal organs. In this paper, I argue that HOT theory has nothing to fear from it either and can consistently account for what happens in such unusual cases. I analyze Cotard syndrome in light of my previous discussion of somatoparaphrenia and thought insertion, and argue that HOT theory can provide a somewhat analogous account without the worry of inconsistency. It is crucial to recognize that there are multiple “self-concepts” and levels of HOTs which can help to provide a more nuanced explanation. With regard to the connection between consciousness and self-consciousness, it is proposed that Cotard patients are indeed capable of having some “I-thoughts” about their bodies and mental states. (shrink)

In this paper, I am generally concerned with certain mental disorders and the doxastic attitudes that sometimes characterize them. According to recent Anglo-American philosophical studies on this topic, the latter involve beliefs that have somehow “gone wrong”: strange or irrational beliefs and cases of “motivated irrationality”. I aim to focus on pathological and deceptive phenomena such as delusion and self-deception. From a phenomenological perspective, these can also be investigated with regard to their experiential content. Adopting this approach, and starting in (...) particular with the eidetic connection between the living body and its own environment, I will examine disorders of the ecological self. Psychiatric delusion, which is at the core of this examination, is a symptom of a great number of mental disorders, such as Capgras disorder, Cotard disorder and schizophrenia. Integrating dominant (propositional) models of delusion which reduce this pathological phenomenon to a certain kind of belief, I propose an eco-phenomenological understanding of its contours. From this perspective, delusion reveals itself primarily as an illusory experience: a delusional value-perception. In particular, I offer a Schelerian-based description of a peculiar case of delusion: Capgras delusion. People who suffer from Capgras delusion claim that an otherwise familiar individual has been replaced by an impostor. I consider, although in its negative variations, the contextual (rather than internalist) character of this type of delusion. (shrink)

Corlett (2019) raises two groups of challenges against the two-factor theory of delusions: One focuses on weighing “the evidence for … the two-factor theory”; the other aims to question “the logic of the two-factor theory” (p. 166). McKay (2019) has robustly defended the two-factor theory against the first group. But the second group, which Corlett believes is in many aspects independent of the first group and Darby (2019, p. 180) takes as “[t]he most important challenge to the two-factor theory raised (...) by Dr. Corlett”, has by large remained. Here I offer my two cents in response to the second group. More specifically, I argue that Corlett’s challenges to the logic of the two-factor theory, concerning modularity, double dissociation and cognitive penetration, seem to be based on some misunderstandings of the two-factor theory. (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)

This paper argues that 'duality' accounts of time, as exemplified by Henri Bergson's, Edmund Husserl's, and John McTaggart's ideas, parallel the decomposition of temporal experience in depressive psychosis into objective and subjective dimensions of time. The paper also proposes to comprehend the full-fledged depressive temporal delusion, in which the subjective flow of time comes to a standstill, via the idea of a double orientation to reality characteristic of schizophrenic delusions. In the depressive temporal delusion a person claims that time is (...) not moving while simultaneously her cognitive orientation in temporal surroundings remains largely unaffected, hence the double orientation. The juxtaposition of temporal experience in depression with the temporal disorientation in dementia enables us to situate the depressive delusion regarding the flow of time in the middle of a proposed scale of the disintegration of normal temporal experience. (shrink)

Clinical delusions are widely characterized as being pathological beliefs in both the clinical literature and in common sense. Recently, a philosophical debate has emerged between defenders of the commonsense position (doxasticists) and their opponents, who have the burden of pointing toward alternative characterizations (anti-doxasticists). In this chapter, I argue that both doxasticism and anti- doxasticism fail to characterize the functional role of delusions while at the same time being unable to play a role in the explanation of these phenomena. I (...) also argue that though a more nuanced view of belief in which mental states are more or less belief-like instills a healthy skepticism towards the precision of folk-psychological concepts, such a stance fails to be of use in building a theory of delusion that will be able to bridge different levels of explanation, such as the phenomenology and neurobiology of delusion. Thus, I advocate moving past the question ‘Are delusions beliefs?’ and their description as propositional attitudes toward the description of the processes that generate delusion, with a view toward explaining, rather than explaining away, the personal-level aspects of the phenomenon that have been made inscrutable by investing in doxastic terminology. (shrink)

This paper raises a slightly uncomfortable question: are some delusional subjects responsible for their delusions? This question is uncomfortable because we typically think that the answer is pretty clearly just ‘no’. However, we also accept that self-deception is paradigmatically intentional behavior for which the self-deceiver is prima facie blameworthy. Thus, if there is overlap between self-deception and delusion, this will put pressure on our initial answer. This paper argues that there is indeed such overlap by offering a novel philosophical account (...) of self-deception. The account offered is independently plausible and avoids the main problems that plague other views. It also yields the result that some delusional subjects are self-deceived. The conclusion is not, however, that those subjects are blameworthy. Rather, a distinction is made between blameworthiness and ‘attributability’. States or actions can be significantly attributable to a subject—in the sense that they are expressions of their wills—without it being the case that the subject is blameworthy, if the subject has an appropriate excuse. Understanding delusions within this framework of responsibility and excuses not only illuminates the ways in which the processes of delusional belief formation and maintenance are continuous with ‘ordinary’ processes of belief formation and maintenance, it also provides a way of understanding the innocence of the delusional subject that does not involve the denial of agency. (shrink)

Bortolotti argues that we cannot distinguish delusions from other irrational beliefs in virtue of their epistemic features alone. Although her arguments are convincing, her analysis leaves an important question unanswered: What makes delusions pathological? In this paper I set out to answer this question by arguing that the pathological character of delusions arises from an executive dysfunction in a subject’s ability to detect relevance in the environment. I further suggest that this dysfunction derives from an underlying emotional imbalance—one that leads (...) delusional subjects to regard some contextual elements as deeply puzzling or highly significant. (shrink)

In this paper we have two main aims. First, we present an account of mood-congruent delusions in depression (hereafter, depressive delusions). We propose that depressive delusions constitute acknowledgements of self-related beliefs acquired as a result of a negatively biased learning process. Second, we argue that depressive delusions have the potential for psychological and epistemic benefits despite their obvious epistemic and psychological costs. We suggest that depressive delusions play an important role in preserving a person’s overall coherence and narrative identity at (...) a critical time, and thus can be regarded as epistemically innocent. (shrink)

Patients suffering from the Cotard syndrome can deny being alive, having guts, thinking or even existing. They can also complain that the world or time have ceased to exist. In this article, I argue that even though the leading neurocognitive accounts have difficulties meeting that task, we should, and we can, make sense of these bizarre delusions. To that effect, I draw on the close connection between the Cotard syndrome and a more common condition known as depersonalisation. Even though they (...) are not delusional, depersonalised patients seem to have experiences that are quite similar to those of Cotard patients. I argue that these experiences are essentially characterised by a lack of subjective character and of two other structural features of experience, which I call ‘the present character’ and ‘the actual character’. Cotard's nihilistic delusions simply consist in taking these anomalous experiences at face value. (shrink)

In this paper we address the ethics of adopting delusional beliefs and we apply consequentialist and deontological considerations to the epistemic evaluation of delusions. Delusions are characterised by their epistemic shortcomings and they are often defined as false and irrational beliefs. Despite this, when agents are overwhelmed by negative emotions due to the effects of trauma or previous adversities, or when they are subject to anxiety and stress as a result of hypersalient experience, the adoption of a delusional belief can (...) prevent a serious epistemic harm from occurring. For instance, delusions can allow agents to remain in touch with their environment overcoming the disruptive effect of negative emotions and anxiety. Moreover, agents are not blameworthy for adopting their delusions if their ability to believe otherwise is compromised. There is evidence suggesting that no evidence-related action that would counterfactually lead them to believe otherwise is typically available to them. The lack of ability to believe otherwise, together with some other conditions, implies that the agents are not blameworthy for their delusions. The examination of the epistemic status of delusions prompts us to acknowledge the complexity and contextual nature of epistemic evaluation, establish connections between consequentialist and deontological frameworks in epistemology, and introduce the notion of epistemic innocence into the vocabulary of epistemic evaluation. (shrink)

In philosophy, psychiatry, and cognitive science, definitions of clinical delusions are not based on the mechanisms responsible for the formation of delusions. Some of the defining features of delusions are epistemic and focus on whether delusions are true, justified, or rational, as in the definition of delusions as fixed beliefs that are badly supported by evidence). Other defining features of delusions are psychological and they focus on whether delusions are harmful, as in the definition of delusions as beliefs that disrupt (...) good functioning. Even if the epistemic features go some way towards capturing what otherwise different instances of clinical delusions have in common, they do not succeed in distinguishing delusions as a clinical phenomenon from everyday irrational beliefs. Focusing on the psychological features is a more promising way to mark the difference between clinical and non-clinical irrational beliefs, but there is wide variability in the extent to which delusions are psychologically harmful, and some everyday irrational beliefs can affect functioning in similarly negative ways. In this chapter we consider three types of belief that share similar epistemic features and exhibit variation with respect to how psychologically harmful they are: (1) delusions of thought insertion, (2) alien abduction beliefs, and (3) self-enhancing beliefs. In the light of the similarities and differences between these cases, we highlight the difficulty in providing an answer to what makes an irrational belief delusional. (shrink)

This paper analyses the phenomenon of strange, rigid beliefs through the lens of predictive processing (PP). By “strange, rigid beliefs” I refer to abstract beliefs about the world for which, according to a rational and scientific worldview, there is no evidence available, yet which people struggle to abandon even when challenged with strong counterarguments or counterevidence. Following recent PP accounts of delusion formation, I show that one explanation for such strangely persistent beliefs can be a breakdown of the predictive machinery (...) itself. However, given how common strange, rigid beliefs are, I argue that there must be another kind of explanation too – one that does not presuppose a malfunction of the prediction engine. This will lead me to develop an alternative account that I will call “hijacking beliefs”. Using the example of supernatural beliefs, I will argue that certain abstract beliefs, when adopted under the right circumstances, are especially hard to dislodge for a predictive mind, as they are evidentially self-protective. Such beliefs may be consistent with a wide range of experiences and therefore hard to falsify, and might also bias future perception, action, and model-updating in ways that make them immune to rational revision. (shrink)

In order to explain delusional beliefs, one must first consider what factors should be included in a theory of delusion. Unlike a one-factor theory, a two-factor theory of delusion argues that not only anomalous experience (the first factor) but also an impairment of the belief-evaluation system (the second factor) is required. Recently, two-factor theorists have adopted various Bayesian approaches in order to give a more accurate description of delusion formation. By reviewing the progression from a one-factor theory to a two-factor (...) theory, I argue that in light of the second factor’s requirements, different proposed impairments can be unified within a consistent belief-evaluation system. Under this interpretation of the second factor, I further argue that the role of a mechanism responsible for detecting bizarreness is wrongly neglected. I conclude that the second factor is a compound system which consists of differing functional parts, one of which functions to detect bizarreness in different stages of delusion; moreover, I hold that the impairment can be one or several of these functional parts. (shrink)

The Capgras delusion is a condition in which a person believes that an imposter has replaced some close friend or relative. Recent theorists have appealed to Bayesianism to help explain both why a subject with the Capgras delusion adopts this delusional belief and why it persists despite counter-evidence. The Bayesian approach is useful for addressing these questions; however, the main proposal of this essay is that Capgras subjects also have a delusional conception of epistemic possibility, more specifically, they think more (...) things are possible, given what is known, than non-delusional subjects do. I argue that this is a central way in which their thinking departs from ordinary cognition and that it cannot be characterized in Bayesian terms. Thus, in order to fully understand the cognitive processing involved in the Capgras delusion, we must move beyond Bayesianism. 1 The Simple Bayesian Model2 Anomalous Evidence and the Capgras Delusion3 Impaired Reasoning4 Setting Priors5 Epistemic Modality6 Delusions of Possibility7 Delusions of Possibility in Different Contexts8 How Many Factors? (shrink)

In this paper I discuss the scientific respectability of delusion as a psychiatric category. First, I present the essentialist objection to the natural kindhood of psychiatric categories, as well as non-essentialism about natural kinds as a response to that objection. Second, I present a nuanced classification of kinds of kinds. Third, drawing on the claim that the attribution of delusion relies on a folk psychological underpinning, I present the mind-dependence objection to the natural kind status of delusion. Finally, I argue (...) that even if delusion as a generic kind stands little chance of being vindicated as a non-essentialist natural kind, we stand to gain from a natural kind methodology regarding subtypes of delusion for which there is evidence of genuine causal signatures and mechanisms. (shrink)

Although delusion is one of the central concepts of psychopathology, it stills eludes precise conceptualization. In this paper, I present certain basic issues concerning the classification and definition of delusion, as well as its ontological status. By examining these issues, I aim to shed light on the ambiguity of the clinical term ‘delusion’ and its extension, as well as provide clues as to why philosophers are increasingly joining the ranks of psychiatrists, psychologists, and neuroscientists in the effort to come to (...) a comprehensive understanding of delusion. (shrink)

Delusions are defined as irrational beliefs that compromise good functioning. However, in the empirical literature, delusions have been found to have some psychological benefits. One proposal is that some delusions defuse negative emotions and protect one from low self-esteem by allowing motivational influences on belief formation. In this paper I focus on delusions that have been construed as playing a defensive function (motivated delusions) and argue that some of their psychological benefits can convert into epistemic ones. Notwithstanding their epistemic costs, (...) motivated delusions also have potential epistemic benefits for agents who have faced adversities, undergone physical or psychological trauma, or are subject to negative emotions and low self-esteem. To account for the epistemic status of motivated delusions, costly and beneficial at the same time, I introduce the notion of epistemic innocence. A delusion is epistemically innocent when adopting it delivers a significant epistemic benefit, and the benefit could not be attained if the delusion were not adopted. The analysis leads to a novel account of the status of delusions by inviting a reflection on the relationship between psychological and epistemic benefits. (shrink)

Somatoparaphrenia is a pathology of self characterized by the sense of alienaton from parts of one’s body. It is usually construed as a kind of delusional disorder caused by extensive right hemisphere lesions. Lesions in the temporoparietal junction are common in somatoparaphrenia but deep cortical regions (for example, the posterior insula) and subcortical regions (for example, the basal ganglia) are also sometimes implicated (Valler and Ronschi 2009). Patients are often described as feeling that a limb belongs to another person and (...) thus attribute ownership of the limb and bodily sensation to someone else. There is also some question as to whether or not the higher-order thought (HOT) theory of consciousness can plausibly account for the depersonalization psychopathology of somatoparaphrenia (Liang and Lane 2009, Rosenthal 2010, Lane and Liang 2010). Liang and Lane argue that it cannot. The HOT theory of consciousness says that what makes a mental state a conscious mental state is that it is the target of a HOT to the effect that “I am in mental state M” (Rosenthal 2005, Gennaro 2012). When the HOT is itself is unconscious, the conscious state is still outer-directed. When the HOT is conscious, we have introspection and so the conscious thought is directed at the mental state. In section I, I briefly review the previous exchange between Lane and Liang and David Rosenthal. In section II, I further explore somatoparaphrenia and the nature of delusion while offering a number of additional replies to Lane and Liang. In section III, I examine the central notions of “mental state ownership” and “self-concepts” in an effort to account especially for the depersonalization aspect of somatoparaphrenia against the background of HOT theory. In section IV, I argue that to the extent that somatoparaphrenia casts doubt on the notion that some thoughts are “immune to error through misidentification” (IEM), the most fundamental aspect of IEM is still consistent with HOT theory. Overall, I argue that HOT theory is left unscathed by the pheneomenon of somatoparaphrenia and can even help to explain what happens in these cases. (shrink)

Clinical delusions have traditionally been characterized as beliefs in psychiatry. However, philosophers have recently engaged with the empirical literature and produced a number of objections to the so-called doxastic status of delusion, stemming mainly from the mismatch between the functional role of delusions and that expected of beliefs. In response to this, an appeal to dispositionalism about the nature of belief has been proposed to vindicate the doxastic status of delusion. In this paper, I first present the objections to attributing (...) beliefs to delusional patients and the application of dispositionalism in the attempt to vindicate doxasticism. I then assess this application and some responses to the objections to the doxastic characterization. Finally, I offer some conclusions about the limits of folk-psychological concepts in the characterization and explanation of complex psychological phenomena such as delusions. (shrink)

Examino a controvérsia sobre como melhor definir o delírio—um sintoma central de patologias como a esquizofrenia e a demência—e apresentarei algumas das principais dificuldades envolvidas em sua caracterização como crenças. A partir disso, tiro conclusões sobre os limites do vocabulário mentalista da dita psicologia do senso comum e sobre a forma como delírios e outros fenômenos elusivos devem ser propriamente caracterizados pela psiquiatria para que uma explicação integrativa destes seja alcançada.

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. (shrink)

There has recently been emphasis put on providing two-factor accounts of monothematic delusions. Such accounts would explain (1) whether a delusional hypothesis (e.g. someone else is inserting thoughts into my mind) can be understood as a prima facie reasonable response to an experience and (2) why such a delusional hypothesis is believed and maintained given its implausibility and evidence against it. I argue that if we are to avoid obfuscating the cognitive mechanisms involved in monothematic delusion formation we should split (...) the first factor (1 above) into two factors: how abnormal experience can give rise to a delusional ‘proto-hypothesis’ and how a ‘proto-hypothesis’ in consort with normal experiences and background information, can be developed into a delusional hypothesis. In particular I will argue that a schizophrenic is faced with the unusual requirement of having to identify an introspectively accessible thought as one's own, and that this requirement of identification is the central experiential abnormality of thought insertion, auditory verbal hallucination, and alien control (i.e. passivity symptoms). Additionally, I will consider non-experiential factors which are required for the formation of a delusional hypothesis. (shrink)

One of the leading and central figures in research on delusions, Max Coltheart, presents and summarises his heretofore work in a short text. Miyazono and Bortolotti present an interesting argument aimed at the charges against the doxastic concept of delusions. Adams, Brown and Friston showcase a predictive-Bayesian concept of delusions. Young criticizes the current changes in the two-factor account of delusions and argues that the role of experience should not be dismissed within it. Kapusta presents an interesting, phenomenological approach to (...) delusions, rooted in the classic works of Karl Jaspers. In the last article, Carruthers takes a look at delusions from a different perspective. He uses them in order to show the weakness of the sense of agency concept as proposed by Wegner. The issue also contains an interview with Jakob Hohwy. In Hohwy’s still-recent book, we can find an interesting, predictive approach to delusions. Hohwy points towards the unobvious connections between delusions and illusions. (shrink)

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)

Three challenges to a unified understanding of delusions emerge from Radden's On Delusion (2011). Here, I propose that in order to respond to these challenges, and to work towards a unifying framework for delusions, we should see delusions as arising in inference under uncertainty. This proposal is based on the observation that delusions in key respects are surprisingly like perceptual illusions, and it is developed further by focusing particularly on individual differences in uncertainty expectations.

In this paper I try to analyze one of the most common psychological syndrome which a considerable number of humans all over the world are suffering from. It’s called “the GodBug Syndrome” and its effects on one’s decisions and choices in life. It’s where a smart educated person is pestered by two contradictory feelings, first that he is “as special creature as nature has yet produced and second that he’s not very special at all.” These twin feelings lead a person (...) to the following conclusion: while he thinks that he is perhaps great, being trapped with a brain that really isn’t big enough for his purposes, perhaps trapped in a corner of an academic discipline, a research field or in some other small place as we will see the hero of the novel under analysis, trapped by his creatureliness, and trapped by life’s very smallness. (shrink)

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)

This chapter identifies and explores a series of challenges raised by the clinical concept of delusion for theories which conceive autonomy as an agency rather than a status concept. The first challenge is to address the autonomy-impairing nature of delusions consistently with their role as grounds for full legal and ethical excuse, on the one hand, and psychopathological significance as key symptoms of psychoses, on the other. The second challenge is to take into account the full logical range of delusions, (...) which may take the form of true or false factual beliefs, positive or negative evaluations, as well as the paradoxical delusion of mental illness. The third and final challenge is to make room for non-pathological or, autonomy-preserving delusions and to offer a credible way of distinguishing between these and pathological or, autonomy-impairing delusions. By setting out these challenges, we are able to, firstly, distinguish between two separate conceptions of objectivity that may be at work in existing accounts of delusions and, secondly, to put a spotlight on an elusive yet inescapable notion of agential success that underlies our thinking about autonomy as well as mental disorder. (shrink)