In his book On Evil, Terry Eagleton offers his readers an eminently readable treatise that combines literary criticism and philosophy in a way that does justice to his complex and charged subject. In my view, Eagleton does what every scholar of literature should attempt to do: make his analysis accessible to a wide reading audience without sacrificing the intellectual rigor of his work. As usual, the book is written beautifully, and Eagleton's sense of humor is highly enjoyable. This is the kind of literary criticism that is accessible to any reasonably educated person, not just to academics.
Eagleton begins On Evil by discussing how the concept of evil has been appropriated by a certain type of political discourse. The implication behind referring to terrorists as "evildoers" and their actions as "pure evil" is that if we accept that there is a rational explanation for acts of terror, we somehow condone them. This, of course, is completely wrong since "rational" and "commendable" are not the same thing. The tendency to refer to terrorists as evil only serves the purpose of shutting down any kind of discussion of their actions. As a result, we are left with no understanding of what they do and what. Consequently, we cannot possibly hope to combat terror since we have precluded any opportunity to analyze terrorism in any meaningful way.
Even though Eagleton ridicules the way certain politicians have appropriated the word "evil," he believes that evil actions and evil individuals do exist. In this, he disagrees not only with a certain brand of liberals but with many Marxists as well. (We have to remember that Eagleton himself is an unapologetic Marxist, which does not preclude him from pointing out the many subjects where he disagrees with his fellow Marxists. It is precisely this kind of intellectual honesty that makes me respect him so much). In Eagleton's view, the nature of evil is metaphysical, in the sense that it aims to destroy being as such, not just certain parts of it. It is the metaphysical nature of evil that Eagleton tries to analyze (and in my view, succeeds in doing so) in On Evil. The most intolerable thing for evil is that anything should exist. Its most important goal is the annihilation of being as such.
In his Living in the End Times, Slavoj Zizek says that the question we need to ask ourselves is not "Is there life after death?" What we should ask instead is, rather, "Is there life before death?" Eagleton echoes this statement in On Evil. He mentions "the worthless purity of those who have never lived", which can lead people to desire to bring destruction to those who have the capacity to enjoy the richness of human existence. It is among those who have never actually allowed themselves to live, to enjoy, to love life that evil has its perfect breeding ground.
Eagleton draws our attention to the paradoxical side of evil that was observed by Hannah Arendt in Eichmann in Jerusalem: A Report on the Banality of Evil (Penguin Classics). Truly evil acts are often perpetrated by "mild-mannered individuals who believe that business is business." Instead of being terrified by this phenomenon, we should see that it offers us hope. Most evil, says Eagleton, is institutional. If we change the entire structure of our society, the kind of evil that plagues our existence today will disappear.