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)

Kengo Miyazono’s Delusions and Beliefs: A Philosophical Inquiry is an attempt to provide a unified account of the nature, pathology, and etiology of delusions. The strength of his book resides in the clarity of arguments and its consistent adoption of a biological explanation of delusions, based on teleo-functionalism about mental states. However, there are some weaknesses in each of his arguments regarding the nature, pathology, and etiology of delusions. Regarding the nature of delusions, teleo-functionalism makes it difficult to confirm that (...) delusions are beliefs. Regarding the pathology of delusions, I suggest that the existence of harmful malfunction is a necessary but not a sufficient condition for a belief to be considered pathological, and that additional evidence is needed to justify the separation of the belief and the holder’s personhood. Regarding the etiology, it is not reasonable to incorporate the prediction error theory into a kind of two-factor theory. Therefore, the details of his arguments require further modification. (shrink)

Are conspiracy theory beliefs pathological? That depends on what is meant by "pathological." This paper begins by unpacking that ill-defined and value-laden term before making the case that widespread conspiracy theory belief should not be conceptualized through the “othering’ perspective of individual psychopathology. In doing so, it adopts a phenomenological perspective to argue that conspiracy theory beliefs can be reliably distinguished from paranoid delusions based on falsity, belief conviction, idiosyncrasy, and self-referentiality. A socio-epistemic model is then presented that characterizes the (...) broader phenomenon of conspiracy theory belief as a product of a sick society plagued by epistemic mistrust and vulnerability to misinformation that is ubiquitous in today’s post-truth world. Finally, it is proposed that for individuals, the harmfulness of conspiracy theory belief is less related to belief content as it is to belief conviction and degree of self-relevant consequentiality. Staging conspiracy theory belief in terms of ideological commitment offers a conceptual framework to estimate behavioral risks and test hypotheses about the effectiveness of interventions along a continuum of belief conviction and associated socio-epistemic dynamics. Interventions should target not only individuals, but the dysfunctional social conditions that give rise to the pervasive and enduring phenomenon of conspiracy theory belief. (shrink)

The aim of this paper is twofold. First, I want to re-examine the epistemic status of elaborated delusions. Bortolotti (2016, 2020) claims that they can be epistemically innocent. However, I will show that this type of delusions is more unique than suggested by the existing analyses of their epistemic status. They typically cause more profound harms than other kinds of delusions, and in most cases, it would be counterproductive to classify them as epistemically beneficial or innocent. I will employ predictive (...) and phenomenological models of delusions and the enactivist notion of sensus communis to explain the harms and possible benefits of elaborated delusions and why I think the existing definition does not fully grasp them. Based on this analysis, I will propose changes to the conditions for epistemic innocence. (shrink)