But 'evil' is a theological and moral term, not a psychological one. I think the problem is that we tend to base morality on having the correct sentiment, so a person incapable of having moral feelings can never become moral. (I actually agree and say that sociopaths are intrinsically amoral, and reserve the term evil for those who could be good but choose not to) People don't behave on rational grounds, usually, but on emotional ones. On the current system of moral reasoning we're working on, however, a person is judged by their intent. If a person simply refrains from killing other people on consequential grounds (i.e., I must not go round slaughtering folks because I don't want to go to jail) this isn't really 'moral' or 'good,' just rational.