Abstract

It is well-known that irrational beliefs are part of a normal healthy life. Even so, some beliefs stand out as exceptionally odd because they do not reflect what people consider to be normal or acceptable. Conventional diagnostic systems in psychiatry habitually characterize extremely outlandish beliefs as delusional, that is, as being abnormal, morbid or pathological. Exactly why a belief is delusional is a matter of great controversy.

Yet there seems to be a vital difference between delusions and other irrational ideas, for example, believing that one is God Almighty or that one is dead, on the one hand, and believing that Princess Diana faked her own death or that that “thirteen” is an unlucky number, on the other. In this presentation I will exemplify some typical delusions from the clinical literature and highlight a set of problems in contemporary philosophical debates, such as, how to define “delusion”, in what sense, if any, delusions are proper beliefs, and the complicated relation between delusion and mainstream religious beliefs.