Where do atheists get their morality from?

[Red Celt]

The morality of social animals is based upon reciprocity. Actions have consequences. I'm not interested in possible worlds; they are a construct of metaphysics. In this world, punching babies has consequences... and those consequences aren't devolved between theism and atheism.

Reciprocity is only one factor guiding the formation of ethical norms in a society. Certain moral duties have decidedly non-reciprocal origins and non-reciprocal expressions, such as "It is morally wrong to rape somebody, even if they raped you first and you are reciprocating." Reciprocity in this capacity does nothing to inform the problem of subjective morality that we as atheists need to grapple with: The problem that a relativistic, atheistic moral worldview RATIONALLY NECESSITATES the possibility that the raping of babies could be considered morally good.

It's not appealing, but it's true and we as atheists need to find a solution to this problem. Not by appealing to ad hoc evo-psych, but by finding ways to mitigate the subjectivity of our morality when it comes to behavior that we think ought to be wrong in all circumstances.

Vincenzo, you know about philosophy... but you don't know it well enough. You're also more than a little flimsy wrt logical fallacies. When you (later) claim that Sam Harris shares your view, as does Dawkins... you're making an appeal to authority. Harris & Dawkins are not the boss of me. Atheists do not have to take the views of authoritative atheists as a position of dogma. I also doubt that you're right when it comes to Dawkins' ethical problems with objective morality. Have you read The Selfish Gene?

Reciprocity is a stronger meme than you allow for. Rather than concentrate on babies (punch them, rape them... you don't like babies very much, do you?) who are not moral agents, how about you concentrate on the reciprocal approach of moral agents?

Atheism is the lack of belief or the belief in the lack of god(s). Assigning anything else to it (whether moral or otherwise) is a fool's errand. So why make that your errand?