Problem of good and evil for an atheist

[Ace Otana]

Your choice is whether to kill the baby who would grow up to be one of the most evil men of the 20th century, or to leave and let history pan out the way it has.

I think going back in time and changing anything would be a serious mistake. Even if the intent was a good one, the outcome could be very bad.
Though hitler did great wrongs, he played a huge role in creating the present day we all know so well. Removing him will create an alternate future with alternate people. You could very well end up removing many millions from ever existing. Doing more damage than hitler did. You could even remove me and yourself completely out of existance.

No matter how good our intentions are, there are many things we should never interfear with. Most importantly, the past.
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I'm going to try and keep on topic so...

If you think killing a baby is ever justified, I think it is safe to say, that you are sick and perveted.

Babies were once used as catapult ammo. Thrown into castle walls to demoralise the enemy forces. Even loaded into cannons. Our todays view on etheics didn't exist a few hundred years ago.

This notion of good and evil had to come from somewhere.

From us. We created the concepts of good and evil and our view on what is considered good and bad developed over many thousands of years. Over a hundred years ago it was ok to beat your wife. It was ok to have them wear a device that prevents them from talking and is somewhat an embarrisment to wear. It was ok to torture people.

So where did it come from?

Read above.

although I cant conclude and prove that it, it explains things much better than anything else.

And so I reject the idea due to lack of evidence. It doesn't seem more plausable at all. Far from it.