Abstract
Monothematic delusions are delusions whose contents pertain to a single
subject matter. Examples include Capgras delusion, the delusion that a loved
one has been replaced by an impostor, and Cotard delusion, the delusion that
one is dead or does not exist. Two-factor accounts of such delusions hold that
they are the result of both an experiential deficit, for instance flattened affect,
coupled with an aberrant cognitive response to that deficit. In this paper
we develop a new expressivist two-factor account of delusion. In contrast
to existing endorsement and explanationist accounts, which treat delusions
as either explanations or endorsements of the contents of these disordered
experiences, we hold that delusional beliefs have an expressive function: they
characterize, in impressionistic terms, what the subject’s experience is like
for them. We show how our account improves upon existing two-factor views
in explaining the central features of monothematic delusions, in particular
the way in which delusional subjects fall short of the ideal of rationality.