Some Taoist writing suggests that good and evil produce each other, to the extent that one can’t recognize one without the presence of the other; structuralists like Saussure have said much the same thing. Evil is sometimes – always? – in the eye of the beholder; one side in a conflict may see an event as an atrocity, while the other side considers it to be furthering the good. For example, from the second chapter of the Tao te Ching (Waley's 1977 translation):
Difficult and easy complete one another.Spence refers to Saint Augustine’s distinction between “moral evil”, bad things that people do by choice, and “natural evil”, bad things that befall us without any human agency (like earthquakes and disease). He raises the possibility that biochemical explanations for vicious acts arguably move them from the moral to the natural realm. (However, he ends up arguing that free will is almost always involved even where there are biological determinants, and that the moral imperative remains.)
Long and short test one another;
High and low determine one another.
I find it hard to believe in an absolute evil: a moral evil that exists outside of any human context, and which if removed would only leave good behind. I’m a relativist at heart; if you take away “evil”, the “good” that remains will divide itself again into good and evil.
However, I must at least to some extent be fooling myself with such rationalism. The existence and persistence of systems of morality implies that the reification of evil (and of good, for that matter) is part of the way the human brain works. One can no less see no difference between good and evil than one can perceive the world without distinguishing figure and ground.
Our ability to see (and be) saints like Mother Theresa requires and determines that we also see (and are) monsters like Hitler.
So, does evil exist? Yes; it exists just as much as cold exists. It is a human experience which depends on the context in which it is perceived. Its relativity does not diminish it’s reality, that is, it’s presence and power in our daily experience.