Folk and Philosophical EpistemologiesA Double Bookkeeping of Sorts by Delusion’s Theoreticians? Clarissa de Rosalmeida Dantas (bio) Delusions are typically regarded as beliefs of a certain kind, both by psychiatrists and by lay people. In “Double Bookkeeping and Doxasticism about Delusion,” Porcher (2019) formulates and assesses two kinds of arguments against doxasticism about delusions, the theoretical stance according to which delusions are a kind of belief. Those arguments, which Porcher calls “the argument from action guidance and the argument from phenomenology” are motivated by a phenomenon sometimes associated with delusions: double bookkeeping, a kind of ambivalence of patients, who “often appear to be living in two parallel but separate worlds: consensual reality and the realm of their hallucinations and delusions” (Sass, 1994, p. 21). Much of the debate around doxastic and anti-doxastic theories of delusions has proceeded mainly through putting forth arguments against the generality of the opposite account. The heterogeneity of delusional experiences is well-acknowledged and both advocates of doxasticism and those of anti-doxasticism resort to clinical descriptions and first-person reports that defy accommodation within the framework under attack. Assessing the argument from action guidance, Porcher considers it to be inconclusive because other cognitive and affective factors might explain the behavioral circumscription while preserving the belief status of delusions, but not least because behavioral circumscription is not a feature of all delusions. Though the author gives more credit to the argument from phenomenology, considering that it “more forcefully undermines characterizations that invest in doxastic terminology,” that argument does not more favor to the generality of an anti-doxastic account than the argument from action guidance. Not all patients express their delusions in figurative and metaphorical language. Many delusions happen to sound like the description in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (American Psychiatric Association, 2013). Hence, my accordance to the negative moral Porcher extracts from the debate: “the heterogeneity of the class of delusion puts pressure on the very possibility of anyone ever arriving at a characterization that is at once general and precise” (2019, p. 115). And I would [End Page 121] like to add: different contexts of usage and different projects may require that the balance between generality and precision of the characterization be set at different levels (see Fulford, Thornton, & Graham, p. 64). In what contexts and for what purposes does a generalizing characterization of delusions as either belief, imagination, or in-between states matter? Not when it comes to understand the experience of delusional patients, Porcher maintains, to which I agree. As Bayne (2010) puts it, “[the] case for regarding a delusion as a doxastic state may differ from patient to patient and may even fluctuate for particular patients from one occasion to another” (p. 334). So, I welcome Porcher’s “divide and conquer suggestion,” although I disagree on where the division should fall. As I see it, it cuts across either both diagnostic categories and the classification of delusions as monothematic or polythematic. What about the context of neuroscience and the purpose of achieving a mechanistic explanation of delusions? Neither here a doxastic nor anti-doxastic characterization is necessary, Porcher defends, to which I also agree. Concepts such as belief and imagination originate in folk psychology and have no known correspondence in terms of cognitive or neural processes. Folk psychology provides the vocabulary and concepts to which we resort for understanding and expressing our mental states, thus in context of psychiatric diagnosis folk psychological thermology matters a lot and here the debate about doxasticism is invested with some importance. As Fulford et al. (2006, p. 69) argue, “’delusion,’ like ‘time,’ is a concept that is relatively easy to use clinically (it is a reliably identifiable symptom) yet peculiarly difficult to define.” The definitions provided in the modern psychiatric classifications are usually taken as a starting point to much of the philosophical work on delusion, but the degree to which those definitions accurately correspond to the way delusion is identified in clinical practice and research is itself a subject of debate and criticism (Fulford et al., 2006, p. 63). In Porcher’s quotation of the definition presented in the Glossary of Technical Terms of the...