First of all, my thanks to John for a very generous introduction. I’m glad to be blogging on Brains when I’m about to start a brand new project. Come September, I’ll be on an AHRC Fellowship exploring the possibility that, in some contexts, cognitions with obvious epistemic pitfalls (such as distorted memories, delusional beliefs and confabulatory explanations) play an important role in the preservation or acquisition of knowledge.
What I plan to do here in the next four weeks is to show how my research question arises from previous work on delusions and other “imperfect cognitions”, and to offer some suggestions about where it could lead.
The nature of delusions is an issue of philosophical controversy. I did argue that they are irrational beliefs, an unexciting and conservative position with respect to the psychiatric literature, but one increasingly under siege by philosophers of mind. I find the debate about the doxastic status of delusions very informative, because it brings to the fore many of our assumptions about the furnishings of the mind – but I don’t wish to resurrect it here. For the purposes of setting the scene for the new project, (clinical) delusions are simply symptoms of psychiatric disorders such as schizophrenia, delusional disorders, amnesia, dementia, which involve perceptual, doxastic, volitional and affective states and impact negatively on the wellbeing of those who report them.
Why all this interest in delusions, you may ask. If you allow me to indulge in an autobiographical digression, I’ve always been completely fascinated by irrationality. At the end of my first degree in Bologna, I wrote a dissertation aspiring to challenge Davidson’s argument against conceptual relativism. For my MA dissertation at King’s College London, I chose to discuss Kuhn’s views about rationality and scientific change. As part of my BPhil in Oxford, I wrote about the rationality debate in cognitive science and philosophy, resisting the idea that human achievements entail rationality. And finally, in my PhD thesis at ANU, I went back to Davidson’s principle of charity and asked why we would ever think that we need to assume rationality to get belief ascription off the ground, given our everyday experience as interpreters of ourselves and others, and the overwhelming evidence against rationality in psychology and psychiatry.
Maybe delusions seemed the right phenomenon to study, because they were always mentioned as examples of radical (as opposed to familiar) irrationality, as the mark of madness. But the theses I have come to defend, that the irrationality of delusions is not different in kind from that of everyday beliefs, and that the epistemic features of delusions are not necessarily responsible for their pathological character, suggest another answer. Delusions are incredibly interesting and deeply unsettling, because they show more clearly than other imperfect cognitions which epistemic faults we are all vulnerable to.
A delusion is typically implausible to start with, and often badly supported by evidence. The content of the delusion is not easily revised and the delusion is not abandoned even if strong evidence or argument against it is made available to the person reporting the delusion. Delusions are likely to conflict with at least some of the person’s beliefs and other cognitive or affective states. Commitment to the content of the delusion is not always adequately reflected in the person’s behaviour and as a result the delusion may fail to guide action. If the list of epistemic features above sounds familiar, it is because most of our beliefs fit that description, to a greater or lesser extent.
Hi Lisa, I am really looking forward to your posts! I don’t know much about the literature in this area, but I did have a course with Martin Davies way back when he was visiting at the Grad Center and we talked about some of this stuff.
I seem to recall one of the debates centered on whether delusions were rational responses to strange phenomenology or whether they were truly irrational beliefs. Is this what you had in mind when you said the view that they were irrational beliefs was coming under siege in philosophy? I probably should read through the SEP article you linked to so sorry if this is a question that is answered there.
Hi Richard
The SEP entry on delusions will be updated soon, as some recent literature on the prediction error theory of delusion formation and on delusions and Bayesianism was not discussed in the original version of the entry written in 2009, and needs to be reviewed. But the entry does discuss two interrelated philosophical questions about delusions, whether they are beliefs and whether they are irrational.
In the post, I was referring to the view that delusions are beliefs as a not very popular one among philosophers these days. Here are just some alternative proposals: delusions are more akin to perceptual than doxastic states Hohwy), they are acts of imagination mistaken as beliefs (Currie), they are failed attempts at believing (Schwitzgebel), they are hybrid states, for instance “besires”, half beliefs and half desires (Egan), or they are alternative realities (Gallagher).
Recently, in a post on my project blog, Imperfect Cognitions, Gerrans suggested that delusions are “instances of unsupervised activity in the default network triggered and or maintained by hypersalient experience”.
Hey Lisa,
Since the issue has come up in comments, readers might be interested in a recent paper defending what you called the “not very popular view” (within the field of philosophy, at least) on doxastic status. Together with John Turri and David Rose (https://philpapers.org/rec/ROSWWS), we argue that monothematic delusions are in fact viewed as clear cases of stereotypical belief, and that this fact gives us cause to reexamine some of the features philosophers have thought stereotypical of belief (particularly when it comes to the question of behavioural circumscription).
Very much looking forward to reading your posts!
Glad to know there are philosophers out there defending the doxastic conception of delusions.
I also agree that behavioural circumscription in normal cognition is an underestimated phenomenon and I’ll read your work with great interest. Matthew Broome and I have a paper in Emotion Review considering evidence about lack of motivation which either prevents beliefs from turning into intentions to act or prevents intentions from converting into action. There are good reasons to believe that failures of motivation are more likely in people with schizophrenic delusions than controls due to a variety of factors ranging from reduced sense of autonomy and relatedness to emotion disturbances.
In my view, this is a promising start in the attempt to explain why people with delusions don’t consistently act on their delusional reports (the so-called phenomenon of double-bookkeeping or behavioural inertia). They have the same type of difficulties in acquiring or preserving motivation to act as any agent does. In addition to that, they may experience further obstacles due to their clinical profile or social context.
Hi Lisa,
I’m intrigued by the point you make at the end. Would you go so far as to say that qua beliefs — or, perhaps better, qua belief-involving states — clinical delusions are no different in kind from everyday instances of cognitive irrationality, and thus that it’s only in virtue of their perceptual, volitional and affective aspects that delusions form a distinctive psychological kind? (Do you even think that they form a distinctive psychological kind at all?) Or would you not go this far? And in that case, then how do you think the cognitive aspects of delusional beliefs are different from everyday ones, if not in their irrationality?
Hi John
My claim is that the irrationality of delusions is no different in kind from that of other beliefs, but delusions may be irrational to a higher degree than typical beliefs.
Are delusions a distinctive psychological kind? I’m not sure we can provide an answer before we gain a better understanding of how delusions come about, but in terms of “surface features”, what makes them different from racist and superstitious beliefs that are widespread in the non-clinical population is that delusions are a cause of alienation and withdrawal. This may be due to their often unusual content and to the extent to which they dominate the lives of the people reporting them, at least in the acute stages.
When we think about overall effects of delusions on wellbeing, I’m not sure we can meaningfully detach their cognitive aspects from their other aspects, and the context in which they arise more generally (e.g., other symptoms of schizophrenia or dementia).
Hopefully my second post clarifies my position a little, but I definitely need to think more about this.