This paper explores the phenomenology of the Capgras and Cotard delusions. The former is generally characterised as the belief that relatives or friends have been replaced by impostors, and the latter as the conviction that one is dead or has ceased to exist. A commonly reported feature of these delusions is an experienced ''defamiliarisation'' or even ''derealisation'' of things, which is associated with an absence or distortion of affect. I suggest that the importance attributed to affect by current explanations of (...) delusional experience can serve to make explicit the manner in which we ordinarily experience the world under a taken-for-granted aspect of affective familiarity. This implicit feeling is, I argue, partly constitutive of our sense of reality. However, so-called ''folk psychology,'' which is generally adopted by philosophers as an initial interpretive backdrop for delusional beliefs and for beliefs more generally, fails to accommodate it. As a consequence, some pervasive philosophical assumptions concerning the manner in which we experience and understand the world, ourselves, and each other are called into question. (shrink)