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)

Does the formation of delusions involve abnormal reasoning? According to the prominent ‘two-factor’ theory of delusions (e.g. Coltheart, 2007), the answer is yes. The second factor in this theory is supposed to affect a deluded individual's ability to evaluate candidates for belief. However, most published accounts of the two-factor theory have not said much about the nature of this second factor. In an effort to remedy this shortcoming, Coltheart, Menzies and Sutton (2010) recently put forward a Bayesian account of inference (...) in delusions. I outline some criticisms of this important account, and sketch an alternative account of delusional inference that, I argue, avoids these criticisms. Specifically, I argue that the second factor in delusion formation involves a systematic deviation from Bayesian updating, a deviation that may be characterized as a bias towards ‘explanatory adequacy’. I present a numerical model of this idea and show that my alternative account is broadly consistent with prominent prediction error models of delusion formation (e.g. Corlett, Murray et al., 2007). (shrink)

Stanford Encyclopedia Entry on Delusions.

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)

RESUMEN Una vez que el foco de la reflexión pasa de las teorías ideales a la aplicación de la justicia social, centrada en las instituciones de las sociedades democráticas, se requiere prestar especial atención a los estilos de vida. Estos tienen una alta incidencia en cómo la justicia es realizada y afectan tanto a la desigualdad económica como a la disponibilidad de los recursos naturales. En nuestras sociedades es posible establecer restricciones a los estilos de vida, especialmente en aquellos casos (...) en que, por el efecto de algunas dinámicas sociales, aquellos se desacoplan de las concepciones del bien. Se defiende que, en tales casos, la base normativa que permite exigir el respeto a los estilos de vida se disuelve y por ello es posible justificar su restricción. ABSTRACT Now that the focus of reflection has shifted from ideal theories to the application of social justice, centered on the institutions of democratic societies, it is necessary to pay special attention to lifestyles, since they not only influence the realization of justice, but also have an effect on economic inequality and the availability of natural resources. In our societies, it is possible to place restrictions on lifestyles, especially in those cases in which, influenced by certain social dynamics, they disengage from conceptions of the good. The article argues that, in those cases, the normative base grounding the demand that lifestyles be respected is dissolved, thus justifying their restriction. (shrink)

RESUMEN Una vez que el foco de la reflexión pasa de las teorías ideales a la aplicación de la justicia social, centrada en las instituciones de las sociedades democráticas, se requiere prestar especial atención a los estilos de vida. Estos tienen una alta incidencia en cómo la justicia es realizada y afectan tanto a la desigualdad económica como a la disponibilidad de los recursos naturales. En nuestras sociedades es posible establecer restricciones a los estilos de vida, especialmente en aquellos casos (...) en que, por el efecto de algunas dinámicas sociales, aquellos se desacoplan de las concepciones del bien. Se defiende que, en tales casos, la base normativa que permite exigir el respeto a los estilos de vida se disuelve y por ello es posible justificar su restricción. ABSTRACT Now that the focus of reflection has shifted from ideal theories to the application of social justice, centered on the institutions of democratic societies, it is necessary to pay special attention to lifestyles, since they not only influence the realization of justice, but also have an effect on economic inequality and the availability of natural resources. In our societies, it is possible to place restrictions on lifestyles, especially in those cases in which, influenced by certain social dynamics, they disengage from conceptions of the good. The article argues that, in those cases, the normative base grounding the demand that lifestyles be respected is dissolved, thus justifying their restriction. (shrink)

In recent times, explanations of the Capgras delusion have tended to emphasise the cognitive dysfunction that is believed to occur at the second stage of two-stage models. This is generally viewed as a response to the inadequacies of the one-stage account. Whilst accepting that some form of cognitive disruption is a necessary part of the aetiology of the Capgras delusion, I nevertheless argue that the emphasis placed on this second-stage is to the detriment of the important role played by the (...) phenomenology underlying the disorder, both in terms of the formation and maintenance of the delusional belief. This paper therefore proposes an interactionist two-stage model in which the phenomenal experience of the Capgras patient is examined, emphasised, and its relation to top-down processing discussed. (shrink)

This paper contrasts an interactionist account of delusional misidentification with more traditional one- and two-stage models. Unlike the unidirectional nature of these more traditional models, in which the aetiology of the disorder is said to progress from a neurological disruption via an anomalous experience to a delusional belief, the interactionist account posits the interaction of top-down and bottom-up processes to better explain the maintenance of the delusional belief. In addition, it places a greater emphasis on the patient’s underlying phenomenal experience (...) in accounting for the specificity of the delusional content. The role played by patient phenomenology is examined in light of Ratcliffe’s recent phenomenological account. Similarities and differences are discussed. The paper concludes that a purely phenomenological account is unable to differentiate between non-delusional patient groups, who have what appear to be equivalent phenomenal experiences to patients suffering from delusional misidentification but without the delusional belief, and delusional groups, something the interactionist model is able to do. (shrink)

Delusions are studied in two philosophical traditions: the continental or phenomenological tradition and the Anglo-American or analytic tradition. Each has its own view of delusions. Broadly stated, phenomenologists view delusions as a disturbed experience whilst most analytic researchers view them as beliefs. It is my contention that the most plausible account of delusions must ultimately incorporate valuable insights from both traditions. To illustrate the potential value of integration I provide a novel model of the Capgras delusion which describes how an (...) analytic, cognitive neuropsychological two-factor account of the Capgras delusion and the phenomenological view of delusions might be integrated. (shrink)

I suggest that we can think of delusional misidentification in terms of systematic errors in the management of mental files. I begin by sketching the orthodox “bottom-up” aetiology of delusional misidentification. I suggest that the orthodox aetiology can be given a descriptivist or a singularist interpretation. I present three cases that a descriptivist interpretation needs to account for. I then introduce a singularist approach, one that is based on mental files, and show how it opens the way for different and (...) potentially more plausible accounts of these three cases. I reflect on how this mental files approach can be viewed either as a supplement to the orthodox aetiology, or as suggesting an altogether different aetiology. I end by addressing a concern surrounding the explanatory power of mental files. (shrink)

It is sometimes said that humans are unlike other animals in at least one crucial respect. We do not simply form beliefs, desires and other mental states, but are capable of caring about our mental states in a distinctive way. We can care about the justification of our beliefs, and about the desirability of our desires. This kind of observation is usually made in discussions of free will and moral responsibility. But it has profound consequences, or so I shall argue, (...) for our conception of the very nature of beliefs and other mental states. Suitably developed, it allows us to draw a line between two distinct ways in which a creature may possess a belief, represent a scene, and fall into error. The first way (which I shall call the 'mindless' way) involves little more than an encoding of information in some way designed to guide appropriate response. This is the common heritage of humans, and many other animals. The second way (which I shall call the 'mindful' way) requires that the creature be capable in addition of a special kind of second-order reflection, and (importantly) be expert at detecting the kinds of situation in which such reflection is called for. The differences between these two ways of 'believing that P' are sufficiently deep and significant to warrant (or so I claim) our treating them as two distinct classes of mental states. For it is only courtesy of the second layer of complexity, I shall argue, that it becomes proper to hold someone accountable for their beliefs or other mental states, and it is this fact of (something like) accountability that in turn raises the most significant challenge for philosophical attempts to give naturalized accounts of meaning, belief, and mentality. (shrink)

The text concerns the role of emotions in delusion formation. Provided are definitions from DSM-V and DSM-IV-R and the problems found in those definitions. One of them, the problem of delusion formation, is described when providing cognitive theories of delusions. The core of the paper is a presentation of the emotional and affective disorders in delusions, especially Capgras delusion and Cotard delusion. The author provides a comparison of the kinds of delusions and the conclusions taken from neuroimaging studies. As a (...) result of the fact that an explanation of delusion formation focusing on emotional problems turns out to be insufficient, the author provides examples of the reasoning impairments which coexist with them. At the end of the article, some hypotheses are proposed concerning the role of emotions and reasoning in delusion formation and the relation between belief disorders and emotional disorders. (shrink)

The aim of this article is to analyze those theories that interpret misidentification delusions in terms of mentalization. The hypothesis under examination holds that a mentalization framework is useful for describing misidentification delusions when identification is thought to be partially based on mentalization. The article provides both a characterization and possible interpretations of such delusions, and possible relations between misidentification and mentalization are scrutinized. Whether the mentalization approach may explain or describe such kinds of mental disorders is considered, with the (...) conclusion that while this approach is unsatisfactory, there is some room for future improvement. (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)

The dominant conception of delusion in psychiatry (in textbooks, research papers, diagnostic manuals, etc.) is predominantly epistemic. Delusions are almost always characterized in terms of their epistemic defects, i.e., defects with respect to evidence, reasoning, judgment, etc. However, there is an individualistic bias in the epistemic conception; the alleged epistemic defects and abnormalities in delusions relate to individualistic epistemic processes rather than social epistemic processes. We endorse the social epistemological turn in recent philosophical epistemology, and claim that a corresponding turn (...) is needed in the study of delusions. It is a turn from the (purely) individualistic conception, which characterizes delusions only by individualistic epistemic defects and abnormalities, to the (partially) social epistemic conception, which characterizes delusions by individualistic as well as social epistemic defects and abnormalities. This paper is intended as an initial step toward such a social epistemological turn. In particular, we will develop a new model of the development of delusions according to which testimonial abnormalities, including testimonial isolation and testimonial discount, are a causal factor in the development of delusions. (shrink)

Maher proposed in 1974 that schizophrenic delusions are hypotheses formed to explain anomalous experiences. He stated that they are “rational, given the intensity of the experiences that they are developed to explain.” Two-factor theorists of delusion criticized Maher’s theory because 1) it does not explain why some patients with anomalous experiences do not develop delusions, and 2) adopting and adhering to delusional hypotheses is irrational, considering the totality of experiences and patients’ other beliefs. In this paper, the notion of the (...) intensity of experience is reappraised to uphold Maher’s basic conception. Regarding 1), I propose that differences in the intensity of anomalous experience are vital to whether the patient forms delusions, while partially reforming his rationality claim regarding 2). Although adopting delusions is irrational, it is inevitable and excusable, given the intensity of the patient’s anomalous experience. With the aid of this notion, it is maintained that anomalous experience is sufficient for the development of delusions, at least in some cases of schizophrenia. Compared to other theories of schizophrenic delusion, Maher’s theory, which embraces the notion of intensity of experience, better explains why such irrational mental states as delusions develop from anomalous experiences, and why delusional patients persist in believing specific thematic content. (shrink)

This paper draws on studies of the Capgras delusion in order to illuminate the phenomenological role of affect in interpersonal recognition. People with this delusion maintain that familiars, such as spouses, have been replaced by impostors. It is generally agreed that the delusion involves an anomalous experience, arising due to loss of affect. However, quite what this experience consists of remains unclear. I argue that recent accounts of the Capgras delusion incorporate an impoverished conception of experience, which fails to accommodate (...) the role played by ‘affective relatedness’ in constituting (a) a sense of who a particular person is and (b) a sense of others as people rather than impersonal objects. I draw on the phenomenological concept of horizon to offer an interpretation of the Capgras experience that shows how the content ‘this entity is not my spouse but an impostor’ can be part of the experience, rather than something that is inferred from a strange experience. (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)

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)

This essay presents a new account of thought insertion. Prevailing views in both philosophy and cognitive science tend to characterize the experience of thought insertion as missing or lacking some element, such as a ‘sense of agency’, found in ordinary first-person awareness of one's own thoughts. By contrast, I propose that, rather than lacking something, experiences of thought insertion have an additional feature not present in ordinary conscious experiences of one's own thoughts. More specifically, I claim that the structure of (...) an experience of thought insertion consists of two distinct elements: a state of ordinary first-person awareness and a sense that this state of awareness is highly unusual. In addition to modeling the experience of thought insertion, I also explain how a delusional pattern of thinking could lead someone who has this kind of experience to adopt a belief that some other entity is inserting thoughts into her mind. Finally, I briefly sketch a neurocomputational framework that could be developed to explain the sense that one's state of first-person awareness is highly irregular. (shrink)

Current models of delusion converge in proposing that delusional beliefs are based on unusual experiences of various kinds. For example, it is argued that the Capgras delusion (the belief that a known person has been replaced by an impostor) is triggered by an abnormal affective experience in response to seeing a known person; loss of the affective response to a familiar person’s face may lead to the belief that the person has been replaced by an impostor (Ellis & Young, 1990). (...) Similarly, the Cotard delusion (which involves the belief that one is dead or unreal in some way) may stem from a general.. (shrink)

Monothematic delusions involve a single theme, and often occur in the absence of a more general delusional belief system. They are cognitively atypical insofar as they are said to be held in the absence of evidence, are resistant to correction, and have bizarre contents. Empiricism about delusions has it that anomalous experience is causally implicated in their formation, whilst rationalism has it that delusions result from top down malfunctions from which anomalous experiences can follow. Within empiricism, two approaches to the (...) nature of the abnormality/abnormalities involved have been touted by philosophers and psychologists. One-factor approaches have it that monothematic delusions are a normal response to anomalous experiences whilst two-factor approaches seek to identify a clinically abnormal pattern of reasoning in addition to anomalous experience to explain the resultant delusion. In this paper we defend a one-factor approach. We begin by making clear what we mean by atypical, abnormal, and factor. We then identify the phenomenon of interest and overview one and two-factor empiricism about its formation. We critically evaluate the cases for various second factors, and find them all wanting. In light of this we turn to our one-factor account, identifying two ways in which ‘normal response’ may be understood, and how this bears on the discussion of one-factor theories up until this point. We then conjecture that what is at stake is a certain view about the epistemic responsibility of subjects with delusions, and the role of experience, in the context of familiar psychodynamic features. After responding to two objections, we conclude that the onus is on two-factor theorists to show that the one-factor account is inadequate. Until then, the one-factor account ought to be understood as the default position for explaining monothematic delusion formation and retention. We don’t rule out the possibility that, for particular subjects with delusions there may be a second factor at work causally implicated in their delusory beliefs but, until the case for the inadequacy of the single factor is made, the second factor is redundant and fails to pick out the minimum necessary for a monothematic delusion to be present. (shrink)

It is often taken for granted in standard theories of interpretation that there cannot be intentionality without rationality. According to the background argument, a system can be interpreted as having irrational beliefs only against a general background of rationality. Starting from the widespread assumption that delusions can be reasonably described as irrational beliefs, I argue here that the background argument fails to account for their intentional description.

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)

Addiction is almost universally held to be characterized by a loss of control over drug-seeking and consuming behavior. But the actions of addicts, even of those who seem to want to abstain from drugs, seem to be guided by reasons. In this paper, I argue that we can explain this fact, consistent with continuing to maintain that addiction involves a loss of control, by understanding addiction as involving an oscillation between conflicting judgments. I argue that the dysfunction of the mesolimbic (...) dopamine system that typifies addictions causes the generation of a mismatch between the top-down model of the world that reflects the judgment that the addict ought to refrain from drugs, and bottom-up input caused by cues predictive of drug availability. This constitutes a powerful pressure toward revising the judgment and thereby attenuating the prediction error. But the new model is not stable, and shifts under the pressure of bottom-up inputs in different contexts; hence the oscillation of all-things-considered judgment. Evidence from social psychology is adduced, to suggest that a similar process may be involved in ordinary cases of weakness of will. (shrink)

Delusions are usually considered as harmful and dysfunctional beliefs, one of the primary symptoms of a psychiatric illness and the mark of madness in popular culture. However, in recent times a much more positive role has been advocated for delusions. More specifically, it has been argued that delusions might be an answer to a problem rather than problems in themselves. By delivering psychological and epistemic benefits, delusions would allow people who face severe biological or psychological difficulties to survive in their (...) environment - although this has obvious epistemic costs, as the delusion is fixed and irresponsive to compelling counterevidence. In other words, it has been argued that delusions are biologically adaptive. The adaptiveness of delusions has been compared by Ryan McKay and Daniel Dennett to a shear pin, a mechanism installed in the drive engine of some machines which is designed to shear whenever the machine is about to break down. By breaking, shear pins prevent the machine from collapsing and allow it to keep functioning, although in an impaired manner. Similarly, when delusions form, they would allow a cognitive or psychological system which is about to collapse to continue its functioning, although in an impaired manner. However, this optimistic picture of delusions risks being undermined by both theoretical and empirical considerations. Using Sarah Fineberg and Philip Corlett’s recent predictive coding account as a paradigmatic model of the biological adaptiveness of delusions, I develop two objections to it: principles of parsimony and simplicity suggest that maladaptive models of delusions have an upper hand over adaptive models; and the available empirical evidence suggests that at least some delusions stand good chances of being psychologically adaptive, but it is unlikely that they also qualify as biologically adaptive. (shrink)

I stipulate and motivate the overlooked problem of demarcating radical skeptics (perceptual and moral) from mentally disordered persons, given that both deny that they know ordinary Moorean propositions (e.g., that they have hands or that killing for fun is morally wrong). Call this ‘the demarcation problem’. In response to the demarcation problem, I develop a novel way to demarcate between mentally disordered persons and radical skeptics in an extensionally adequate way that saves the appearance that radical skeptics are not mentally (...) disordered persons (at least not typically). Finally, I examine how a Moorean, non-skeptical epistemologist would compare radical skeptics with the mentally disordered in terms of what Plantinga calls internal and external rationality. Perhaps surprisingly, by Moorean lights, the mentally disordered fare better than the radical skeptic in terms of (internal) rationality. The upshot is that for Mooreans skeptical philosophy is more of an epistemic evil than mental disorder. (shrink)

Cognitive Science, Volume 46, Issue 7, July 2022.

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.

Jennifer Radden has drawn attention to two features of delusion, ambivalence and subjectivity, which are problematic for theories of delusion that treat delusions as empirical beliefs. She argues for an ‘attitude’ theory of delusion. I argue that once the cognitive architecture of delusion formation is properly described the debate between doxastic and attitude theorists loses its edge. That architecture suggests that delusions are produced by activity in the ‘default mode network’ unsupervised by networks required for decontextualized processing. The cognitive properties (...) of these networks explain the features of delusion which generate the debate between doxastic and attitude theorists. (shrink)

Bernard Williams has argued that, because belief aims at getting the truth right, it is a conceptual truth that we cannot directly will to believe. Manyothers have adopted Williams’ claim that believers necessarily respect truth-conducive reasons and evidence. By presenting increasingly stronger cases, I argue that, on the contrary, believers can quite consciously disregard the demand for truth-conducive reasons and evidence. The irrationality of those who would directly will to believe is not any greater than that displayed by some actual (...) believers. So, our inability to directly will to believe is a contingent truth (at best). (shrink)

Dans ce qui suit, je décrirai un modèle pour la formation et la maintenance des délires polythématiques rencontrés dans la schizophrénie, en adéquation avec le modèle pour les délires décrit par Brendan Maher. Les délires polythématiques y sont considérés comme les conclusions d’arguments déclenchés par l’apophénie et qui comportent des erreurs de raisonnement très communes, telles que le sophisme post hoc et le bais de confirmation. Je décris tout d’abord la structure du raisonnement qui conduit au délire de référence, de (...) télépathie et d’influence, en distinguant entre les arguments délirants de type primaire, secondaire, tertiaire et quaternaire. Ces quatre niveaux d’arguments correspondent respectivement à une phase de nature instancielle, inductive, interprétative au niveau monothématique et, enfin, interprétative au niveau polythématique. Je m’attache ensuite à déterminer de manière précise quelles sont les étapes fallacieuses dans le raisonnement correspondant. J’expose également le rôle de l’apophénie dans l’élaboration des idées délirantes. Enfin, je m’attache à décrire le rôle joué par les hallucinations dans le présent modèle.We proceed to describe a model for the formation and maintenance of polythematic delusions encountered in schizophrenia, which is in adequation with Brendan Maher’s account of delusions. Polythematic delusions are considered here as the conclusions of arguments triggered by apophenia that include some very common errors of reasoning such as post hoc fallacy and confirmation bias. We describe first the structure of reasoning which leads to delusions of reference, of telepathy and of influence, by distinguishing between the primary, secondary, tertiary and quaternary types of delusional arguments. These four levels of arguments correspond to a stage the nature of which is repectively instantial, inductive, interpretative at a monothematic level and interpretative at a polythematic level. We also proceed to identify accurately the fallacious steps in the corresponding reasoning. We expose then the role of apophenia in the elaboration of delusional ideas. Lastly, we describe the role played by the hallucinations in the present model. (shrink)

A common reaction to functional diversity is to group entities into clusters that are functionally similar. I argue here that people are diverse with respect to reasoning-related processes, and that these processes satisfy the basic requirements for evolving entities: they are heritable, mutable, and subject to selective pressures. I propose a metric to quantify functional difference and show how this can be used to place psychological processes into a structure akin to a phylogenetic or evolutionary tree. Three species concepts are (...) repurposed from biology and used to understand relationships in that tree. (shrink)

A growing number of studies in both the scientific and the philosophical literature have drawn on a Bayesian predictive processing framework to account for the formation of delusions. The key here is that delusions form because of disrupted prediction error signalling. Parrott’s recent critique argues that the framework is incomplete in two respects: it leaves unclear why delusional hypotheses are selected over none at all or over more plausible alternatives; it leaves unclear how exactly it is that delusional hypotheses are (...) generated in the first place. In this paper, we defend the framework’s explanatory power by way of showing how it can go a long way in helping disentangle these concerns. We take up each of them in turn. As for the first, our argument turns on two claims: a) believing nothing, although possible in principle, may not be a viable procedure in the circumstances; b) alternative hypotheses may be rendered unavailable for selection, due to aberrant prediction errors. As for the second concern, we distinguish three ways in which delusional hypotheses may be initially acquired, all of which are based on experience broadly construed. (shrink)

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.

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. (shrink)

Philosophers have been long interested in delusional beliefs and in whether, by reporting and endorsing such beliefs, deluded subjects violate norms of rationality (Campbell 1999; Davies & Coltheart 2002; Gerrans 2001; Stone & Young 1997; Broome 2004; Bortolotti 2005). So far they have focused on identifying the relation between intentionality and rationality in order to gain a better understanding of both ordinary and delusional beliefs. In this paper Matthew Broome and I aim at drawing attention to the extent to which (...) deluded subjects are committed to the content of their delusional beliefs, that is, to whether they can be regarded as authors of their beliefs (Moran 2001). We consider several levels of commitment one can have to a reported belief, delusional or otherwise, and we distinguish between _ownership_ and _authorship_ of beliefs (Gallagher 2000). After examining some examples of belief authoring (or lack thereof) in psychopathology, we argue that there is no straight-forward and unitary answer to the question whether deluded subjects author their beliefs. Nevertheless, introducing the notion of authorship in the debate can significantly contribute to the philosophical literature on the rationality of delusions and can also have important implications for diagnosis and therapy in psychiatry. (shrink)

I argue that some cases of delusions show the inadequacy of those theories of interpretation that rely on a necessary rationality constraint on belief ascription. In particular I challenge the view that irrational beliefs can be ascribed only against a general background of rationality. Subjects affected by delusions seem to be genuine believers and their behaviour can be successfully explained in intentional terms, but they do not meet those criteria that according to Davidson (1985a) need to be met for the (...) background of rationality to be in place. (shrink)

Philosophers are interested in the phenomenon of thought insertion because it challenges the common assumption that one can ascribe to oneself the thoughts that one can access first-personally. In the standard philosophical analysis of thought insertion, the subject owns the ‘inserted’ thought but lacks a sense of agency towards it. In this paper we want to provide an alternative analysis of the condition, according to which subjects typically lack both ownership and authorship of the ‘inserted’ thoughts. We argue that by (...) appealing to a failure of ownership and authorship we can describe more accurately the phenomenology of thought insertion, and distinguish it from that of non-delusional beliefs that have not been deliberated about, and of other delusions of passivity. We can also start developing a more psychologically realistic account of the relation between intentionality, rationality and self knowledge in normal and abnormal cognition. (shrink)

The Spinozan theory of belief fixation holds that mentally representing truth-apt propositions leads to immediately believing them. In this paper, I explore how the theory fares as a defence of doxasticism about delusions (the view that they are beliefs). Doxasticism has been criticised on the grounds that delusions typically do not abide by rational standards that we expect beliefs to conform to. If belief fixation is Spinozan, I argue, these deviations from rationality are not just compatible with, but supportive of, (...) their status as beliefs. (shrink)

There is evidence indicating that the Capgras delusion is grounded in some kind of anomalous experience. According to the endorsement model, the content of the delusion is already encoded in the Capgras subject's experience, and the delusion is formed simply by endorsing that content as veridical. Elisabeth Pacherie and Sam Wilkinson have in different ways attempted to articulate a comprehensive defence of this strategy, but here I argue that the endorsement model cannot be defended along the lines envisioned by either (...) of them. I then offer a more promising way of spelling out the model, according to which the anomalous experience implicated in Capgras is metaphorical in character. (shrink)

In this paper we defend the doxastic conception of delusions against the metacognitive account developed by Greg Currie and collaborators. According to the metacognitive model, delusions are imaginings that are misidentified by their subjects as beliefs: the Capgras patient, for instance, does not believe that his wife has been replaced by a robot, instead, he merely imagines that she has, and mistakes this imagining for a belief. We argue that the metacognitive account is untenable, and that the traditional conception of (...) delusions as beliefs should be retained. (shrink)

Although delusions are typically regarded as beliefs of a certain kind, there have been worries about the doxastic conception of delusions since at least Bleuler’s time. ‘Anti-doxasticists,’ as we might call them, do not merely worry about the claim that delusions are beliefs, they reject it. Reimer’s paper weighs into the debate between ‘doxasticists’ and ‘anti-doxasticists’ by suggesting that one of the main arguments given against the doxastic conception of delusions—what we might call the functional role objection—is based on a (...) fallacy. She also draws attention to certain parallels between delusions and what she calls “nihilistic philosophical doctrines,” such as the skeptical position that we have no .. (shrink)

A popular approach to monothematic delusions in the recent literature has been to argue that monothematic delusions involve broadly rational responses to highly unusual experiences. Campbell calls this the empiricist approach to monothematic delusions, and argues that it cannot account for the links between meaning and rationality. In place of empiricism Campbell offers a rationalist account of monothematic delusions, according to which delusional beliefs are understood as Wittgensteinian framework propositions. We argue that neither Campbell's attack on empiricism nor his rationalist (...) alternative to empiricism is successful. (shrink)