Delusions and Beliefs

A Philosophical Inquiry

Kengo Miyazono

• Publisher: Routledge
• Year: 2018
• ISBN:
  9781351985352
• Edition: 1
• Topic: Philosophy
• Subtopic: Philosophy History & Theory

What sort of mental state is a delusion? What causes delusions? Why are delusions pathological? This book examines these questions, which are normally considered separately, in a much-needed exploration of an important and fascinating topic, Kengo Miyazono assesses the philosophical, psychological and psychiatric literature on delusions to argue that delusions are malfunctioning beliefs. Delusions belong to the same category as beliefs but - unlike healthy irrational beliefs - fail to play the function of beliefs.

Delusions and Beliefs: A Philosophical Inquiry will be of great interest to students of philosophy of mind and psychology and philosophy of mental disorder, as well as those in related fields such as mental health and psychiatry.

1
Delusions as malfunctional beliefs

1.1 Overview

A delusion is a belief that is held despite obvious counterevidence and that is not explained by the person’s social, cultural, or religious background. Delusions are very often false, and their content can be bizarre. Delusions are typically seen in people with schizophrenia, but they can also be seen in association with a variety of conditions, including dementia, brain injury, drug abuse, etc.¹

Throughout this book, the term ‘delusion’ will be used in the clinical sense. The term is also used in the non-clinical sense, typically referring to false or ungrounded ideas, including self-deceptions, daydreams, religious beliefs (e.g., The God Delusion (2006) by Richard Dawkins), superstitions, and obsolete scientific theories (e.g., Aristotelian physics). Those non-clinical ‘delusions’ will not be discussed in this book unless they overlap ‘delusions’ in the clinical sense (e.g., clinical delusions with religious content).

Delusions are divided into subcategories. A fine-grained distinction is usually made according to the themes or topics of delusions. For example, the delusion of persecution involves the idea of being harmed, harassed, or persecuted by individuals or groups (e.g., ‘My colleagues are trying to prevent me from being promoted’). The Capgras delusion involves the idea of a familiar individual being replaced by an imposter (e.g., ‘My wife has been replaced by a shape-shifting alien that looks exactly like her’). In addition to the fine-grained distinctions, there are some coarse-grained distinctions. A popular coarse-grained distinction is the one between monothematic and polythematic delusions (Davies et al., 2001; Coltheart, 2013). A monothematic delusion is specific to a particular theme. Polythematic delusions, in contrast, involve more than one theme, often constituting a delusional system. The Capgras delusion is often monothematic,² while the delusion of persecution is often polythematic, co-occurring with the delusion of reference (e.g., ‘All other passengers of this train are talking about me’), the delusion of grandeur (e.g., ‘I have a special power to predict future events’), etc.

Some examples would be useful in order to get a clearer grasp of delusions:

Case 1: the delusion of persecution / the delusion of reference

A Thirty-One-Year-Old Woman with Chronic Schizophrenia. The patient had been ill for seven years. At the time of the interview, she reported olfactory and somatic hallucinations but no auditory or visual hallucinations. She noticed an occasional unexplained powdery smell about her body – something like the smell of baby powder – and was distressed by the experience of physical blows raining down on her head on a daily basis. Marked paranoia was present; she avoided all contact with her family, believing that they would harm her if they knew of her location. She also avoided public places, being generally distrustful of other people. She believed that people followed her with their eyes and gossiped about her whenever she went out in public. The only places that she was prepared to frequent on a relatively regular basis were the gym (at times when other people were unlikely to be present) and a local church that she had started attending.

(Davies et al., 2001, p. 135)

Case 2: the Capgras delusion

DS was a 30-year-old Brazilian man who had been in a coma for three weeks following a head injury (right parietal fracture) sustained in a traffic accident. During the subsequent year, he made remarkable progress in regaining speech, intelligence, and other cognitive skills. He was brought to us by his parents principally because of his tendency to regard them as imposters. When we first saw him he appeared to be an alert and fairly intelligent young man who was not obviously hysterical, anxious or dysphoric. A ‘mini’ mental status exam (serial sevens, three objects, writing, orientation in time and place, etc.) revealed no obvious deficits in higher functions, and there was no evidence of dementia. The most striking aspects of his disorder were that he regarded his father as an ‘imposter’ and he had a similar, although less compelling, delusion about his mother. When asked why he thought his father was an imposter his response was ‘He looks exactly like my father but he really isn’t. He’s a nice guy, but he isn’t my father, Doctor’.

(Hirstein & Ramachandran, 1997, p. 438)

Case 3: anosognosia for hemiplegia

Patient L.A.-O (clinical record NA 472, 1980) was a 65-year-old, right-handed woman who was admitted to the emergency department of our hospital on the evening of 2 July 1980. Shortly before admission she had suddenly developed left hemiplegia without loss of consciousness. Alert and cooperative, she claimed that the reason for her hospitalization was sudden weakness and annoying paresthesia of the right limbs; her narrative, supplied in a mild state of anxiety, was indeed accompanied by sustained massage of the allegedly hyposthenic right inferior limb. She also claimed that the left hand did not belong to her but had been forgotten in the ambulance by another patient. On request, she admitted without hesitation that her left shoulder was part of her body and inferentially came to the same conclusion as regards her left arm and elbow, given, as she remarked, the evident continuity of those members. She was elusive about the forearm but insisted in denying ownership of the left hand, even when it had been passively placed on the right side of her trunk. She could not explain why her rings happened to be worn by the fingers of the alien hand.

(Bisiach & Geminiani, 1991, pp. 32–33)

This book tries to answer three questions about delusions:

• (1) The nature question: What is a delusion? In particular, what kind of mental state is it? The standard answer in psychiatry is that delusions are beliefs. This idea, called ‘the doxasticism about delusions’, is the standard view in psychiatry, and it is what I presupposed when I said in the beginning of this chapter that a delusion is ‘a belief that is held despite obvious counterevidence and that is not explained by the person’s social, cultural, or religious background’. But is doxasticism really true? Delusions have a number of peculiar features that are not belief-like. For instance, delusions do not seem to have the belief-like sensitivity to evidence. Is the fact that delusions have these peculiar features consistent with the doxastic conception of delusions?
• (2) The pathology question: Delusions (in the clinical sense) are pathological mental states. This means that delusions, together with other symptoms, warrant clinical diagnoses and treatments.³ Why are delusions pathological? What distinguishes pathological delusions from non-pathological mental states, such as non-pathological irrational beliefs? Are delusions pathological because they are more irrational than non-pathological irrational beliefs? Or, are they pathological because they are stranger than non-pathological irrational beliefs?
• (3) The etiology question: What is the cause of a delusion? How is it formed? It is widely believed that delusions (at least many of them) are formed in response to some abnormal data.⁴ Perhaps a delusion is the explanatory hypothesis a person adopts to make sense of abnormal data (e.g., the Capgras delusion as an explanation of the abnormal data generated by abnormal autonomic activities). But do abnormal data explain everything about the process of delusion formation? Are abnormal data sufficient for someone to form a delusion? If not, what are the additional factors?

In the previous debates on delusions, these questions tend to be discussed independently from each other and in relation to different lines of inquiry: the nature question has been discussed mainly in the philosophy of mind; the etiology question, in contrast, has been examined in psychiatry and cognitive science; and the pathology question has been a topic in the philosophy of psychiatry.⁵ However, discussing these questions separately is potentially problematic because they are closely related; the answer to one question can have implications for how another question is answered. For example, if your answer to the nature question is that delusions are beliefs, then you might answer the etiology question by saying that delusions are the product of some troubles in the belief formation process. Again, if your answer to the etiology question is that delusions are the product of some troubles in the process of belief formation, then you might answer the pathology question by saying that delusions are pathological because of the troubles. I will say more about the connections between these questions in the following chapters.

In this book, I take the connections between the three questions very seriously. My discussions of the questions are interrelated in such a way that my answers to them constitute a unified and coherent understanding of delusions. The central hypothesis of this book, which I call ‘the malfunctional belief hypothesis’, is that delusions are malfunctional beliefs. They belong to the category of belief and, hence, doxasticism is correct (which is my answer to the nature question). However, unlike non-pathological irrational beliefs, they fail to perform some functions of belief (which is the crucial part of my answer to the pathology question). More precisely, delusions directly or indirectly involve some malfunctioning cognitive mechanisms.⁶ And an empiricist account of the delusion formation process (which answers the etiology question) makes the malfunctional belief hypothesis empirically credible.

The category of heart, according to one view,⁷ is defined in terms of the distinctively heart-like function, i.e., the function of pumping blood. All (and only) members of this category have the function of pumping blood. But this does not mean that all the members of this category actually perform the function of pumping blood. Diseased or malformed hearts have the function of pumping blood and thus belong to the category of heart, but they do not perform the function. In other words, they are malfunctional hearts. A delusion, according to my hypothesis, is analogous to a diseased or malformed heart. The category of belief, just like the category of heart, is defined in terms of distinctively belief-like functions, which I tentatively call ‘doxastic functions’. This is the basic idea of teleo-functionalism, which is the theoretical foundation of this book. (I will say more about teleo- functionalism in the next section.) All (and the only) members of the category of belief have doxastic functions. But this does not mean that all the members actually perform the functions. Delusions, according to my hypothesis, have doxastic functions and thus belong to the category of belief, but they do not perform the functions (or, more precisely, delusions directly or indirectly involve some cognitive mechanisms that fail to perform their functions). They are malfunctional beliefs.

Here is a brief overview of this book:

• Chapter 2: Nature. The central puzzle concerning the nature question comes from a seemingly incoherent pair of ideas: Delusions are beliefs (the doxasticism about delusions), and delusions have a number of features that are not belief-like (the causal difference thesis). Both ideas are at least prima facie plausible, but there is a clear tension between them. One solution to the puzzle is to endorse one and deny the other. This ‘incompatibilist’ response assumes that the two ideas are not compatible with each other and hence at least one of them should be rejected. Teleo-functionalism about beliefs, on the other hand, suggests an alternative, ‘compatibilist’ response, according to which the two ideas do not rule out one another. For example, there is nothing incoherent with the idea that diseased or malformed hearts belong to the category of heart despite the fact that they have some features that are not heart-like, e.g., failing to pump blood. Similarly, according to teleo-functionalism, there is nothing incoherent about the idea that delusions belong to the category of belief despite the fact that they have some features that are not belief-like.
• Chapter 3: Pathology. This chapter explores the features of delusions that are responsible for their being pathological. First, I critically examine the proposals according to which delusions are pathological because of their strangeness, their extreme irrationality, their resistance to folk psychological explanations, and the impaired responsibility–grounding capacities of people with delusions. The proposals are problematic because they invite some counterexamples as well as theoretical difficulties. An alternative account comes from Wakefield’s harmful dysfunction analysis of disorder, according to which a disorder is a condition that involves harmful malfunctions (or dysfunctions). Congestive heart failure, for example, is a disorder because a heart is harmfully malfunctioning in that condition. Following Wakefield, I will argue that a delusion is a disordered or pathological mental state because it is a harmfully malfunctional state.
• Chapter 4: Etiology. This chapter defends ‘the empiricism about delusions’, according to which delusions are formed in response to abnormal data. More precisely, this chapter defends a particular kind of empiricism called ‘the two-factor theory’. The two-factor theory states that abnormal data constitute a causal factor (‘the first factor’ or ‘factor 1’), but another causal factor (‘the second factor’ or ‘factor 2’) is also needed to explain the process of del...

Table of contents

• Cover
• Half Title
• Series Page
• Title
• Copyright
• Dedication
• Contents
• Acknowledgments
• 1 Delusions as malfunctional beliefs
• 2 Nature
• 3 Pathology
• 4 Etiology
• Conclusion: a biological account of delusions
• Index