So the Lucifer effect, although it focuses on the negatives -- the negatives that people can become, not the negatives that people are -- leads me to a psychological definition. Evil is the exercise of power. And that's the key: it's about power. To intentionally harm people psychologically, to hurt people physically, to destroy people mortally, or ideas, and to commit crimes against humanity. If you Google "evil," a word that should surely have withered by now, you come up with 136 million hits in a third of a second.