Capacities and dispositions: reflections on Good and Evil from a forensic psychiatrist

‘A capacity for good and a capacity for evil are one and the same capacity. To realise the good, dispositions are necessary’ St. Thomas Aquinas I start with this quote from Aquinas because I want to examine what psychology and psychiatry might have to tell us about the problem of evil. They have little to say about the classic problems of evil: how God allows evil to exist in a loving, good and godly world; nor about the distinction between human and natural evils, nor the problem of free will. But it seems to me that the concept of ‘dispositions ’ might link with psychological capacities for of thinking, feeling, believing and acting. So I want to look at the mental dispositions that make evil possible and I am going to do this by concentrating on the experience of those who have done evil things; what they say about them and what others say about them. I want to use what I have learnt from those who tread the Via Dolorosa; and I want to start by acknowledging their part in my moral education. I am also grateful to my colleagues in forensic psychiatry and psychotherapy for giving me the time to talk about thes