Delusional Atmosphere and the Sense of Unreality

Introduction Recent approaches to delusions in philosophy and the cognitive sciences generally construe them as propositional attitudes that arise due to a combination of anomalous perceptual contents and cognitive disturbances. For example, Stone and Young (1997) claim that certain delusional beliefs are explanations of affectless and thus strange perceptual experiences, which are arrived at and maintained due to reasoning biases. Davies, Coltheart, Langdon and Breen (2001) offer a slightly different explanation, according to which the delusional content is integral to perception. The belief is then generated in the same way as most other beliefs, via the unquestioning acceptance of perceptual content as veridical. So, in their view, the problem stems not from faulty reasoning but from a failure to veto certain anomalous perceptual contents. An alternative approach is proposed by Campbell (2001), who suggests that the delusional belief causes the associated perception, rather than vice versa. However, what his „rationalist‟ account continues to share with perception-first or „empiricist‟ accounts is a commitment to explaining delusions in terms of causal relationships between perceptual and belief contents. The emphasis of most recent discussions is upon monothematic, circumscribed delusions, with the Capgras delusion (the belief that a familiar has been replaced by an impostor) receiving most attention, followed by the Cotard delusion (the belief that one is dead or has ceased to exist). However, there is a tendency to think of delusions more generally in terms of propositional attitudes and associated perceptual contents.