Double Bookkeeping in Delusions: Explaining the Gap between Saying and Doing more

Delusions are usually regarded as irrational belief like states that are symptoms of a variety of psychiatric disorders, among which schizophrenia, dementia and delusional disorders. The doxastic account of delusions is the view that delusions are genuine instances of belief. One powerful objection to the doxastic account is that delusions are not beliefs because, differently from beliefs, they do not lead to action in the relevant circumstances. For instance, people with schizophrenic delusions may fail to manifest commitment to the content of their delusions either verbally or behaviourally. They may endorse attitudes that conflict with their delusions, provide bad reasons or no reasons at all for endorsing their delusions or fail to act on their delusions. This is also known in the literature as the phenomenon of ‘double bookkeeping’.

In this chapter, I shall defend the doxastic account of delusions by arguing that people may fail to act on their delusions even if they genuinely believe the content of their delusions. I shall attempt to explain the gap between reporting a state with apparent conviction and behaving in a way that is not consistent with the report by appealing to two kinds of considerations. First, as people with delusions are not perfectly rational agents, they suffer from attitude-behaviour inconsistencies. Second, people with delusions may fail to acquire or to maintain the motivation to act on their beliefs. Both explanations of the gap between saying and doing apply not just to delusional states, but to belief states more generally, although in people with delusions rationality of beliefs and motivation to act may be compromised to a greater extent than in people without.