Good and evil is something I think quite a lot about. And it ties in, I suppose, to the epitomical question of the Human civilisation: what happens when we die? Now, I'm not religious: I am agnostic, I think. One thing I'm not is superstitious, so I definitely don't believe in ghosts and such. Not sure why. But anyway, it's still a question that haunts the mind (at least, it does mine). Because, in the end, what defines good and evil? How do we know if we've actually been good people in our lives? Eventually this doesn't even come down the idea of life after death, or reincarnation, but in fact our desire to do at least a little good in the world.

As a side note, before I get more into the philosophical thought process, I always think that 'evil' is a very strong word: good and evil are not exactly antipodes. Evil seems irrevocable, good does not. So, perhaps consider evil as a misnomer that actually means 'bad'.