The backside of a piece of paper was created when the paper was made. You can check it out at a papermill. Now you know. Anything else?
If you understand that, then you should also understand everything has an opposite, and also the absence of light, absence of goodness. Our mistake is in assuming there is always a modicum of intelligence brought into a discussion. Let's summarize:
1. Evil is the absence of goodness.
2. Evil is the opposite of good.
3. In scripture, God said He created both (and/or the possibility thereof)
People who have no belief in Go can skip #3. Hard to believe you knew nothing about this until this thread.