People seem to believe some pretty strange things; at least they say things that suggest that they do. Among the more dramatic of these are the various monothematic delusions which have recently been the focus of much philosophical discussion:¹ Patients suffering, for example, from the Capgras syndrome claim that a loved one, typically a spouse or parent, has been replaced by an impostor; patients suffering from the Cotard syndrome claim that they are dead. Monothematic delusions are of interest to philosophers of mind, not because of any particular clinical interest, but because it is deeply puzzling just how to take these patients' claims: Do these patients really believe what they claim, or are their claims to be understood in other ways, perhaps metaphorically or perhaps as the expression of a propositional attitude other than belief? What makes it difficult to credit these patients' claims as expressions of belief is not simply their unbelievable, sometimes even pragmatically self-defeating contents. How, for example, could anyone believe that they are literally dead? It is also that these claims are typically not accompanied by the behavioral, cognitive, and affective responses that we expect of someone who genuinely believes what these claims suggest. Most Capgras patients, for example, don't take action to find their missing loved one, (e.g. reporting their absence to the police); most seem curiously unconcerned as to the fates of these missing loved ones.