What if Everyone was Atheist?

[robvalue]

Karma doesn't teach you right from wrong, it rewards or punishes certain behaviours. Whether those behaviours are actually "good" or "bad" is entirely up for debate. Morality isn't about getting rewards, it's about doing the right thing because it is the right thing. When asked to justify the rules of Karma, you use real world reasoning like everyone else. You don't just say "because Karma says so", so whether Karma says so or not is irrelevant.

We know what hurts us, so we know that if we do it to others, it hurts them. We know what makes us happy, so if we do it to others it generally makes them happy. It's not a lot more complex than that. We have evolved as cooperative, empathetic animals on the whole. That's just reality. You seem to need an extra layer of explanation on top of this, but it's superfluous.

You are suggesting what a theoretical atheist would be like, who doesn't know right from wrong, while ignoring the reality that most atheists are good moral people. We're here right now, we're not theoretical.