ABSTRACT
Psychopaths are a problem.' They are a problem for the courts, which do not know whether to punish them: for their families, who do not know whether to trust them; for neuropsychiatry researchers, who do not know what is wrong with them; and for psychiatrists, who do not know how to treat them, or even what to call them. As a result, they are an intriguing problem for philosophers, raising all manner of intertwined conceptual questions about moral knowledge and responsibility.
