An Analytic View of Delusion

Abstract: 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 analysed. This suggests finally a way susceptible of improving the efficiency of cognitive therapy for delusions. The purpose of this article is to present, as far as I know, a novel account of several types of delusions observed in psychoses. This account results from a logical analysis of delusions, where delusions classically found in psychoses are regarded as conclusions resulting from fallacious arguments. Although their conclusion appears obviously false, delusional arguments are described here as arguments for which the determination of the defective step can sometimes prove nontrivial. The description of delusions as fallacious arguments1 leads finally to several suggestions, which could allow to reinforce the effectiveness of cognitive therapy2. I am very grateful to David Kingdon, Albert Ellis, Eugen Fischer and Robert Chapman for very helpful comments on earlier drafts.