I think that we all know what evil is. We have a sense of what's evil, and certainly killing innocent people is evil. We're less sure about what is good. There's sort of good, good enough, could be better - but absolute good is a little harder to define.
“Once you come up with a premise, you have to work out how it all happened. It's a bit like coming up with a spectacular roof design first. Before you can get it up there, you need to build a solid foundation and supporting structure.”