Question for the Atheist: What is Evil?

I thought about this tonight as I listened to the Bahnsen vs. Stein debate on YouTube:

In debating God many people bring up the "problem" of evil. There is a more fundamental problem before that one: In an atheistic worldview what is the definition of evil?

If one uses the word, "bad" or "good" as a part of the answer, he or she begs the question. From what I have heard from atheists, the answer is always changing depending on the community consensus, and thus, in a materialistic worldview, morality is always evolving towards something "better". But then again, I just used the word, "better". What is "better"? It begs the question and raises another: If the community decides on the moral consensus, then was what Hitler did really evil in Nazi Germany? Wouldn't an atheist have to say, "No, not for them, but only for us living now in our society."? The whole moral fabric of the world unravels at this logic.

I won't even talk about how logic can logically be used by an atheist. I'll let you listen to Bahnsen to get that straight! And all of this from atheists, who claim to be the "most" rational people- the most "scientific" people out there today.

For the Christian the answer is simple: Evil is anything that is in contrast to the moral character of God. That is a clear and unchanging truth outside of our opinions or personal likes or dislikes, and outside of our subjective feelings of happiness or unhappiness. This worldview alone can rationally uphold proper ethics and the larger justice system in the world today. And as Jesus said, "you will know the truth and the truth shall set you free." (John 8:32)