Online research in philosophy

Abstract Studies of irrationality in cognitive psychology have usually looked at areas where humans might be expected to be rational, yet appear not to be. In this paper the other extreme of human irrationality is examined: the delusion as it occurs in psychiatric illness. A parallel is suggested between the delusion as an aberration of cognition and some illusions which result from aberrations within optics. It is argued that, because delusions are found predominantly within certain limited areas of cognitive functioning, they may represent a form of mental aberration which may tell us something about the abstract properties of mind. Possible implications of this model for several areas of cognitive science are discussed.

A comprehensive theory of the structure and cognitive function of the human imagination, and its relationship to perceptual experience, is developed, largely through a critique of the account propounded in Colin McGinn's Mindsight. McGinn eschews the highly deflationary (and unilluminating) views of imagination common amongst analytical philosophers, but fails to develop his own account satisfactorily because (owing to a scientifically outmoded understanding of visual perception) he draws an excessively sharp, qualitative distinction between imagination and perception (following Wittgenstein, Sartre, and others), and because of his fatally flawed, empirically ungrounded conception of hallucination. In fact, however, an understanding of perception informed by modern visual science will enable us to unify our accounts of perception, mental imagery, dreaming, hallucination, creativity, and other aspects of imagination within a single coherent theoretical framework.

The present article proposes a logical account of delusions, which are regarded as conclusions resulting from fallacious arguments. This leads to distinguish between primary, secondary, ..., n-ary types of delusional arguments. Examples of delusional arguments leading to delusion of reference, delusion of influence, thought-broadcasting delusion and delusion of grandeur are described and then analyzed. This suggests finally a way susceptible of improving the efficiency of cognitive therapy for delusions.

A comprehensive theory of the structure and cognitive function of the human imagination, and its relationship to perceptual experience, is developed, largely through a critique of the account propounded in Colin McGinn's Mindsight. McGinn eschews the highly deflationary (and unilluminating) views of imagination common amongst analytical philosophers, but fails to develop his own account satisfactorily because (owing to a scientifically outmoded understanding of visual perception) he draws an excessively sharp, qualitative distinction between imagination and perception (following Wittgenstein, Sartre, and others), and because of his fatally flawed, empirically ungrounded conception of hallucination. In fact, however, an understanding of perception informed by modern visual science will enable us to unify our accounts of perception, mental imagery, dreaming, hallucination, creativity, and other aspects of imagination within a single coherent theoretical framework.

Subjects with delusions profess to believe some extremely peculiar things. Patients with Capgras delusion sincerely assert that, for example, their spouses have been replaced by impostors. Patients with Cotard’s delusion sincerely assert that they are dead. Many philosophers and psychologists are hesitant to say that delusional subjects genuinely believe the contents of their delusions.2 One way to reinterpret delusional subjects is to say that we’ve misidentified the content of the problematic belief. So for example, rather than believing that his wife is has been replaced by an impostor, we might say that the victim of Capgras delusion believes that it is, in some respects, as if his wife has been replaced by an impostor. Another is to say that we’ve misidentified the attitude that the delusional subject bears to the content of their delusion. So for example, Gregory Currie and co-authors have suggested that rather than believing that his wife has been replaced by an impostor, we should say that the victim of Capgras delusion merely imagines that his wife has been replaced by an impostor.3.