One of the philosophical discussions stimulated by the recent scientific study of psychopathy concerns the mental illness status of this construct. This paper contributes to this debate by recommending a way of approaching the problem at issue. By relying on and integrating the seminal work of the philosopher of psychiatry Bill Fulford, I argue that a mental illness is a harmful unified construct that involves failures of ordinary doing. Central to the present proposal is the idea that the notion of failure of ordinary doing, besides the first personal experience of the patient, has to be spelled out also by referring to a normative account of idealised conditions of agency. This account would have to state in particular the conditions which are required for moral responsibility. I maintain that psychopathy is a unified enough construct that involves some harms. The question whether the condition involves also a failure of ordinary doing, as this notion is understood in this paper, is not investigated here.
