What is the nature of evil?

What is the nature of evil?
“It’s the one characteristic that connects all the defendants, a genuine incapacity to feel with their fellow men. Evil, I think, is the absence of empathy.”
“In my work with the defendants (at the Nuremberg Trails 1945-1949) I was searching for the nature of evil and I now think I have come close to defining it. A lack of empathy. It’s the one characteristic that connects all the defendants, a genuine incapacity to feel with their fellow men. Evil, I think, is the absence of empathy.” – Captain G. M. Gilbert, the Army psychologist assigned to watching the defendants at the Nuremberg trials.