Was speaking on evil at the Battle of Ideas this morning, in favour of keeping the concept. I agree it can risk obscuring, not diagnosing, the common complaint against it. Though it's very expressivism - 'pure evil' - is useful, keeping the horror of what might be called evil in view, and reminding us that trying to understand is not the same as entirely explaining: there is something unspeakable about evil.

That said, the Christian tradition, drawing on Aristotelian ethics, does have much to say on the subject, namely that evil is the absence of good, the privatio boni doctrine of Thomas Aquinas.

It might be a lack of values, and so nihilistic. It might be a lack of virtue, or the practical intelligence that allows life to flourish. It might be a lack of appropriate early attachments between mother and child - the empirically well supported analysis from psychotherapy. It might be a lack of meaning, which as Joseph Brodsky points out, is what is exposed in 'turning the other cheek':

‘The other cheek here sets in motion not the enemy’s sense of guilt (which he is perfectly capable of quelling) but exposes his senses and faculties to the meaninglessness of [evil].’

All in all, the nothingness of evil gathers a lot of understandings together, scientific, moral and theological. It is nothing, almost as in Burke’s ‘It is only necessary for the good man to do nothing for evil to triumph.’

I argued that it is also important to see that this account of evil is not evil as the opposite of good, but as the absence of good. This is not a Manichean view of the world, the approach much modern ethics assumes - the utilitarian idea that there is pleasure and pain, or that there is right and wrong.

Rather, evil is a concept that is best at home in virtue ethics: good and evil are related not as north is to south, but as north to not-north - or even better, as hot is to cold, as one member of the audience pointed out to me afterwards.

With evil, life is not as it is supposed to be. Or more strongly, life is as it is supposed not to be in some basic, fundamental way.