What is "Evil"? and why does it exist?

I thought this might be an appropriate topic today. For the word "evil" came up frequently after September 11th. The hijackers joined the ranks of murderers, rapists and despots that we consider "evil".

But what, really, is evil? Not looking for definition by action, i.e. someone who flies a plane into a tower, but what really IS it? And why does it exist? Does it have some strange role to play in our development and history, or is it simply an aberration of our nature?

I think ignorance comes first, since that breeds fear, and fear breeds hate. Which brings me back to this quote from earlier in the thread:

"According to a recent Gallup Poll taken among 1,236 adults... more than one-half believe in the devil (or 55%, with 8% not sure and 37% who don't believe the evil one exists). One in ten claim to have talked to the devil. Some 49% believe that people are at times possessed by the devil, and 22% are not sure, leaving 35% of the population who do not believe in demonic possession."

If this poll is representative, then it (to the extent that it shows an acceptance of the supernatural) indicates a disturbing abundance of ignorance imo. Doesn't the key to fighting (or promoting) ignorance lie largely in how children are raised by their parents and society?

But what can be done to combat ignorance once fear and hate have already taken root? There are always some who will reject any education that interferes with a view of the world they have already grown comfortable with. This loathing or unwillingness to change ones ways in the face of reason might be considered another contributor to "evil". We could simply call it "pigheadedness" ;-)

So... is it possible for someone who has only been raised in an environment of love, respect, and enlightenment to discover a desire and ability within his or herself to commit inhumane acts?