Wickedness: A Philosophical Essay

p. 60

The relation of madness to badness in our thought is subtle: “On the one hand, the idea that wickedness is a form of madness is very natural, because bad conduct is so readily seen as unintelligible. To say, ‘I simply don’t understand how they could act like that’ is a quite direct form of condemnation. To say, ‘What did you mean by it?’ is to ask for justification; if no meaning can be shown which will make the act intelligible, then it will be considered wrong. On the other hand, however, madness counts as an excuse. It is assumed that so far as people are mad they cannot help what they do. Extending this medical model to cover the whole area of wickedness would therefore excuse everybody equally, flattening out the whole spectrum of degrees of responsibility, and putting what’s genuinely unfortunate on the same footing as the sorest and most deliberate crimes.”