Elisabeth Pacherie is a research fellow in philosophy at Institut Jean Nicod, Paris. Her main research and publications are in the areas of philosophy of mind, psychopathology and action theory. Her publications include a book on intentionality (_Naturaliser_ _l'intentionnalité_, Paris, PUF, 1993) and she is currently preparing a book on action and agency.

ABSTRACTThis article intends to reconsider the epistemological status of delusional beliefs on the basis of Wittgenstein’s conception of certainty. Several works over the last two decades have compared delusional beliefs with so-called hinge propositions, which – according to Wittgenstein – function as expressions of objective certainty. This gives rise to a paradox. On the one hand, delusions are compatible to Wittgensteinian certainties in some respects; on the other hand, they contradict beliefs shared by other members of the community, which makes (...) them different from ‘normal’ certainties. In order to address this issue, I use Moyal-Sharrock’s taxonomy of hinge propositions. This taxonomy allows one to distinguish between different types of hinge propositions; all types share the same features, but these features are manifested in a variety of ways. Thus, delusional beliefs might also be regarded as constituting a specific type of hinge propositions. This move makes it possible to resolve the paradox and to identify the special epistemic features of delusional beliefs. (shrink)

This chapter introduces the rationalist model of delusions. It begins by presenting John Campbell’s seminal proposal that delusions are caused top-down by pathological Wittgensteinian framework or hinge beliefs. After presenting Campbell’s rationalist account of delusions, the chapter raises and examines prominent objections by Tim Bayne & Elisabeth Pacherie as well as by Tim Thornton. The former make an important distinction between the aetiological top-down cognitive part and the epistemological rationalist framework part of Campbell’s account. The thesis that delusions are caused (...) top-down by pathological beliefs is not equivalent to the thesis that delusions are Wittgensteinian framework certainties. This chapter endorses this distinction. While the arguments against the top-down aspect are found to be more convincing – which motivates popular two-factor theories – the rationalist framework model of delusions is defended as an epistemologically promising account of delusion. Finally, this chapter examines a range of developments that have been made taking Campbell’s rationalism as a starting point. Most prominently the section examines Eilan’s early development of rationalism and Rhodes and Gipps’ proposal that delusions are not framework propositions but a product of their absence. (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.

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)

In this paper, we consider how certain longstanding philosophical questions about mental representation may be answered on the assumption that cognitive and perceptual systems implement hierarchical generative models, such as those discussed within the prediction error minimization framework. We build on existing treatments of representation via structural resemblance, such as those in Gładziejewski :559–582, 2016) and Gładziejewski and Miłkowski, to argue for a representationalist interpretation of the PEM framework. We further motivate the proposed approach to content by arguing that it (...) is consistent with approaches implicit in theories of unsupervised learning in neural networks. In the course of this discussion, we argue that the structural representation proposal, properly understood, has more in common with functional-role than with causal/informational or teleosemantic theories. In the remainder of the paper, we describe the PEM framework for approximate Bayesian inference in some detail, and discuss how structural representations might arise within the proposed Bayesian hierarchies. After explicating the notion of variational inference, we define a subjectively accessible measure of misrepresentation for hierarchical Bayesian networks by appeal to the Kullbach–Leibler divergence between posterior generative and approximate recognition densities, and discuss a related measure of objective misrepresentation in terms of correspondence with the facts. (shrink)

Some monothematic types of delusions may arise because subjects have unusual experiences. The role of this experiential component in the pathogenesis of delusion is still not understood. Focussing on delusions of alien control, we outline a model for reality testing competence on unusual experiences. We propose that nascent delusions arise when there are local failures of reality testing performance, and that monothematic delusions arise as normal responses to these. In the course of this we address questions concerning the tenacity with (...) which delusions are maintained, their often bizarre content, the patients’ inability to dismiss them, and their often circumscribed character. (shrink)

Some monothematic types of delusions may arise because subjects have unusual experiences. The role of this experiential component in the pathogenesis of delusion is still not understood. Focussing on delusions of alien control, we outline a model for reality testing competence on unusual experiences. We propose that nascent delusions arise when there are local failures of reality testing performance, and that monothematic delusions arise as normal responses to these. In the course of this we address questions concerning the tenacity with (...) which delusions are maintained, their often bizarre content, the patients' inability to dismiss them, and their often circumscribed character. (shrink)

Predictive processing (PP) is now a prominent theoretical framework in the philosophy of mind and cognitive science. This review focuses on PP research with a relatively philosophical focus, taking stock of the framework and discussing new directions. The review contains an introduction that describes the full PP toolbox; an exploration of areas where PP has advanced understanding of perceptual and cognitive phenomena; a discussion of PP's impact on foundational issues in cognitive science; and a consideration of the philosophy of science (...) of PP. The overall picture is that PP is a fruitful framework, with exciting new directions awaiting exploration. (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 discuss the role played by disturbed phenomenology in accounting for the formation and maintenance of the Capgras delusion. Whilst endorsing a two-stage model to explain the condition, I nevertheless argue that traditional accounts prioritise the role played by some form of second-stage cognitive disruption at the expense of the significant contribution made by the patient’s disturbed phenomenology, which is often reduced to such uninformative descriptions as “anomalous” or “strange”. By advocating an interactionist model, I argue that (...) the delusional belief constitutes an attempt on the part of the patient to explain his/her initially odd and somewhat disturbed phenomenal content and, moreover, that the delusion then structures the patient’s experience such that what he/she perceives is an impostor. This fact is used to explain the delusional belief’s maintenance and resistance to revision. Thus, whilst accepting that second-stage cognitive disruption has a part to play in explaining the Capgras delusion, the emphasis here is placed on the role played by the patient’s changing phenomenal content and its congruence with the delusional belief. Unlike traditional two-stage models, which posit a unidirectional progression from experience to belief, the interactionist model advocates a two-way interaction between bottom-up and top-down processes. The application of this model to other delusional beliefs is also considered. (shrink)

Explanations of Capgras delusion and prosopagnosia typically incorporate a dual-route approach to facial recognition in which a deficit in overt or covert processing in one condition is mirror-reversed in the other. Despite this double dissociation, experiences of either patient-group are often reported in the same way – as lacking a sense of familiarity toward familiar faces. In this paper, deficits in the facial processing of these patients are compared to other facial recognition pathologies, and their experiential characteristics mapped onto the (...) dual-route model in order to provide a less ambiguous link between facial processing and experiential content. The paper concludes that the experiential states of Capgras delusion, prosopagnosia, and related facial pathologies are quite distinct, and that this descriptive distinctiveness finds explanatory equivalence at the level of anatomical and functional disruption within the face recognition system. The role of skin conductance response as a measure of ‘familiarity’ is also clarified. (shrink)

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

This paper explores early Australasian philosophy in some detail. Two approaches have dominated Western philosophy in Australia: idealism and materialism. Idealism was prevalent between the 1880s and the 1930s, but dissipated thereafter. Idealism in Australia often reflected Kantian themes, but it also reflected the revival of interest in Hegel through the work of ‘absolute idealists’ such as T. H. Green, F. H. Bradley, and Henry Jones. A number of the early New Zealand philosophers were also educated in the idealist tradition (...) and were influential in their communities, but produced relatively little. In Australia, materialism gained prominence through the work of John Anderson, who arrived in Australia in 1927, and continues to be influential. John Anderson had been a student of Henry Jones, who might therefore be said to have influenced both main strands of Australian philosophical thought. (shrink)

If Australasian philosophers constitute the kind of group to which a collective identity or broadly shared self-image can plausibly be ascribed, the celebrated history of Australian materialism rightly lies close to its heart. Jack Smart’s chapter in this volume, along with an outstanding series of briefer essays in A Companion to Philosophy in Australia and New Zealand (Forrest 2010; Gold 2010; Koksvik 2010; Lycan 2010; Matthews 2010; Nagasawa 2010; Opie 2010; Stoljar 2010a), effectively describe the naturalistic realism of Australian philosophy (...) of mind. In occasional semi-serious psychogeographic speculation, this long-standing and strongly-felt intellectual attitude has been traced back to the influences of our light, land, or lifestyle (Devitt 1996, x; compare comments by Chalmers and O’Brien in Mitchell, 2006). Australasian work in philosophy of mind and cognition has become more diverse in the last 40 years, but is almost all still marked, in one way or another, by the history of these debates on materialism. (shrink)

The phenomenology of agency and perception is probably underpinned by a common cognitive system based on generative models and predictive coding. I defend the hypothesis that this cognitive system explains core aspects of the sense of having a self in agency and perception. In particular, this cognitive model explains the phenomenological notion of a minimal self as well as a notion of the narrative self. The proposal is related to some influential studies of overall brain function, and to psychopathology. These (...) elusive notions of the self are shown to be the natural upshots of general cognitive mechanisms whose fundamental purpose is to enable agents to represent the world and act in it. (shrink)