The rationality of delusions

ILCLI Open Seminar

Institute for Logic, Cognition, Language and Information (ILCLI)
Tuesday, November 28th, 2017, 15:30 am.
Ángeles Eraña (Instituto de Investigaciones Filosóficas, UNAM).


There has been some debate regarding the epistemic status of delusions. Not only is there no agreement regarding whether delusions have any epistemic value, but also whether they are beliefs (or, for that matter, doxastic attitudes at all).

We will give reasons to take delusions to be beliefs and will argue that they have an important rational aspect. Delusions do not only help in making sense of unusual and powerful experiences (Bortonlini and Mameli 2012) –and thus allow us to reason properly-, but more importantly they allow subjects to efficiently convey information and thus be part of social settings. Even though it has been argued that this latter characteristic of delusions is a psychological virtue, we will show that it is also an epistemic one.

Our argument will rest on the following tenets: effective communication is an adaptive feature of human beings. In accordance with Mercier and Sperber (2011), we hold that reasoning has evolved and persisted mainly because it enhances the former adaptive feature. If this is the case, and we accept that the main goals of argumentation are social, then we can understand a sense in which being rational involves being able to function in social settings. If this is the case, and given that rationality is an epistemic virtue, we conclude that delusions are epistemically virtuous.


Venue: Carlos Santamaria Zentroa, Room A1.


(Attendance is free, but it should be notified in advance to