London: Routledge, 2011.
Introduction to Radden Symposium
Article first published online: 1 FEB 2013
© 2013 Blackwell Publishing Ltd
Mind & Language
Volume 28, Issue 1, pages 55–56, February 2013
How to Cite
Langdon, R. and Coltheart, M. (2013), Introduction to Radden Symposium. Mind & Language, 28: 55–56. doi: 10.1111/mila.12007
- Issue published online: 1 FEB 2013
- Article first published online: 1 FEB 2013
Jennifer Radden's book On Delusion (Thinking in Action)1 is a philosopher's panoramic exploration of many facets of delusional belief. She discusses the clinical, cultural and religious contexts of delusion, the ethics of assessing moral responsibility in delusional people (especially when they have committed crimes that were prompted by their delusions), how delusions might be understood by cognitive science, the epistemological status of delusions (is it correct to regard them as beliefs?) and much more. Her book was discussed at a one-day workshop organized by the Macquarie University node of the ARC Centre for Cognition and its Disorders and the Macquarie Research Centre for Agency, Value and Ethics in February 2012, with five speakers presenting discussion of ideas from the book followed by a commentary on these discussions by the author. This set of articles resulted.
Certain themes recur throughout these papers. Many of them, for example, acknowledge how heterogeneous delusional conditions are, and that they are heterogeneous in a number of different ways: in the content of the delusional belief, for example, and in etiology (Coltheart notes that Capgras delusion has been seen in fourteen different kinds of neuropathological condition). Gerrans points out that some delusions present as dream-like or imaginistic mental states, rather than being like beliefs proper, which he proposes are associated with heightened activation of the brain's ‘default system’. Sometimes delusions are ‘encapsulated’—that is, the deluded person does not act on the basis of what appears to be believed—but in other cases there is such delusion-based action, such as the homicidal acts committed by some people with the folie à deux condition, as described by Langdon
Another form of heterogeneity, much discussed throughout Radden's book and also here by Coltheart and by Hohwy, concerns the distinction between monothematic and polythematic delusions. Opinions differ, however, with regard to how we ought to tackle that distinction. In places in Radden's book this distinction is discussed in terms of the ‘clinical coal-face’, the point being that monothematic delusions appear to present more in neurological clinics, whereas polythematic delusions appear to present more in psychiatric clinics. Coltheart instead focuses on the fact that there's a well-worked-out neuropsychological explanation for a variety of monothematic delusions (the two-factor theory of Langdon, Coltheart and colleagues) but attempts have not yet been made to apply this theory to polythematic delusions (though Coltheart sketches some ways in which this might possibly be done).
Hohwy wants to tackle this monothematic/polythematic distinction by using a Bayesian framework to hypothesise individual differences in uncertainty settings that can explain why some individuals present with monothematic delusions while others present with polythematic delusions.
Another frequent theme in Radden's book and in many of the papers here (such as those by Gerrans, Hohwy and Langdon) is the importance of phenomenology and of retrospective analyses of detailed case studies so as to inform conceptions and theoretical models of delusions. Cognitive neuropsychiatry has learned much about delusion from conversations with deluded individuals about their delusions and the phenomenology of these delusions.
Murphy takes a different tack by considering how the folk attribute delusions to others on the basis of a folk epistemology (a set of expectations about what normally controls the acquisition of beliefs). He focuses particularly on the delusional status, or not, of religious beliefs. In doing so he aims to make sense of the DSM-IV definitional requirement that beliefs are not delusions if they are shared by others (articles of religious faiths, for example).
Radden concludes this set of articles by commenting on all of them and bringing to light a couple of new issues. One of these concerns whether or not there can be delusional feelings. The other has to do with the importance of personal-level explanations, which are still important, Radden argues, even if we think that subpersonal mechanisms are primarily responsible for the initial generation and adoption of delusional beliefs.