Interpreting evil is difficult. In Midgley's 2001 "Preface to the Routledge Classics edition" of her 1984 Wickedness: A Philosophical Essay, she says that if all human choices are mechanistic and there's no free will, "we would have to view ourselves also" — in addition to other people who have committed atrocities — "as tools or vehicles of the same kind". Alternatively, maybe we have free will but there's no shared standard to evaluate what we do with it; perhaps "each of us wanders alone in a moral vacuum, spinning values out of our own entrails like spiders," but then "we have ceased to be social creatures altogether." (Later in the book, she adds another risk of claiming that power motives as natural to animals: "power-worship seems to follow because what seems inevitable may command approval.") She says her book aims to distinguish "various forms and combinations of immoralism, relativism, subjectivism and determinism" whose Enlightenment origins are based in "an admirable reaction against the gross abuses that long attended the practices of blame and punishment," and "a determination to make human conduct as intelligible scientifically as the rest of the physical world," even if they do not achieve the correct answer.
In the book, she says: "Skepticism about it [wickedness] has three main forms. First...the idea that no acts are really wrong. Next comes the thought that — though there are wrong acts — nobody actually commits them. And finally comes the thought that — though people do commit them — they never do it on purpose, and so are not responsible." But we don't really believe these things. We cannot refrain from moral judgment. As she puts it:
"To inhibit these reactions would be to treat them [other people] not as people at all, but as some kind of alien impersonal phenomena. Since it is not possible to treat oneself in this way, this would produce a bizarre sense of total isolation in the universe. It cannot actually be done. The need to see ourselves and others as on essentially the same moral footing is in fact so deep that nobody gets anywhere near carrying out this policy. What it usually amounts to is a quite local moral campaign directed against the actual process of blaming. Moral judgment is by no means withheld; it is simply directed with exceptional ferocity against those caught blaming and punishing culprits accused of more traditional offences. This carries guidance of a negative kind for occasions when one is confronted with these offences oneself—namely 'Don't blame or punish.' That advice can sometimes be suitable and useful. But it is extremely limited. Most of life does not consist of such occasions, and most moral difficulties call for other principles, with their background of other moral judgments."
She isn't very concerned with exceptions to the rule, whatever the rule may turn out to be. Although Barbara Wootton worries that reckoning about the existence of psychopaths may "ultimately shatter the whole idea of moral responsibility," Midgley replies that "all conceptual schemes run into difficulties and paradoxes when they are used for awkward and unusual cases."
Everyone occasionally suffers a failure of willpower to do the right thing, but deliberately choosing evil is something different.
"Aristotle made an interesting distinction between people of weak will, who do wrong against their real wishes and intentions, and vicious people, who do wrong contentedly and with conviction. ... Contentedly vicious people do not as a rule describe themselves as vicious, nor even think their actions wrong. They tend either to justify them or to reject moral questions as pointless and irrelevant."
She believes it's important to recognize this:
"Indignant rejection of this myth [of the Fall] in recent times has been due to real misuses of it. But the consequences of trying to do without any such notion may not have been fully understood. There really is a deep, pervasive discrepancy between human ideals and human conduct. In order to deal with this, we need to recognize it, not to deny it.
Midgley asks whether wickedness might someday be treated medically as mental illness is.
"To return, then to the general problem — wickedness is not the same thing as madness, nor as a genuine eccentric morality. Both madness and honest eccentric thinking constitute excuses. And the notion of an excuse only works if there can be some cases which are not excusable, cases to which it does not apply. The notion of real wickedness is still assumed as a background alternative. Yet that notion is still hard to articulate.
The reason why it is so hard is, I suggest, that we do not take in what it means to say that evil is negative. We are looking for it as something positive, and that positive thing we of course fail to find. If we ask whether exploiters and oppressors know what they are doing, the right answer seems to be that they do not know, because they carefully avoid thinking about it — but that they could know, and therefore their deliberate avoidance is a responsible act."
Normal, good people have complex motives including a concern for other people and an ability to prioritize these motives.
"Exploiters and oppressors, war-makers, executioners and destroyers of forests do not usually wear distinctive black hats, nor horns and hooves. The positive motives which move them may not be bad at all; they are often quite decent ones like prudence, loyalty, self-fulfillment and professional conscientiousness. The appalling element lies in the lack of the other motives which ought to balance these — in particular, of a proper regard for other people and of a proper priority system which would enforce it. That kind of lack cannot be treated as a mere matter of chance. Except in rare psychopaths, we attribute it to the will. The will has steadily said 'No', just as Mephistopheles does. But because 'No' is such a negative thing to say, the mind has often not admitted fully what was happening. The staff officer, when he saw the army struggling in the mud [because orders had been thoughtlessly given to them to advance through it], was thunderstruck. Only then did his systematic negligence become clear to him. When it did, he had the grace to be horrified. Once the point was put before him, he could see it. He was capable of remorse, which not everybody is in that situation. Now this capacity for remorse seemed to Aristotle an indication of weak will rather than of vice. But these are surely not sharp alternatives. They are rather ends of a spectrum of clear-headedness about wrong-doing, on which all of us are placed somewhere."
Later, she brings up Mephistopheles again, in the context of enduring motives of destruction:
"...aggressive tendencies of this moderate kind do not answer to the essentially diabolical formula of a truly wicked motive, the interest in destruction for its own sake. When Mephistopheles tells Faust that he is the spirit which always denies, he is expressing something very different from a sharp, impulsive, wish to attack. That 'always' gives quite another colour to the business. Destruction as a policy is not just aggression. It is hatred. This is not a single, natural motive, but a considered attitude, in the end, a way of life. It represents a decision, not an original distinct motive."
To enable wicked motives and deeds, people sometimes have some kind of personality split. Their wicked self needs to justify their actions to their normal self.
"The question why one is behaving alternatively like two quite different people is one that cannot fail to arise. The answer 'I just happen to be two people' has never been found to be very satisfactory. Butler's point, then, seems sound, but it is a matter of degree, not a complete dichotomy. The more chronic, continuous and well-established is the self-deception, the deeper and more pernicious the vice. But some self-deception is probably needed if actions are to be called vicious at all."
Some of our anger is in response to real threats, but some is imagined.
"Specific grievances wear out; the unchangingness of group hostilities marks them as fraudulent. They are not responses to real external dangers, but fantasies. We erect a glass at the border of our own group, and see our own anger reflected against the darkness behind it."