Can objective morality exist in Atheism?

[theVOID]

That's what I meant. You seem to keep switching sides. If morality is relative to "societal norms" it's not "ultimate". If it's not "ultimate" it does not matter who survives and who dies.

Of course it matters, it matters to US, we are the only people who care about our own continued existence as a species, because only in society can we survive, we are not independent animals, we evolved to be in groups, it is a survival mechanism, safety in numbers. Were we to have societies that didn't consider murder wrong we would effectively be a suicidal species, we needed each other in the past just to survive - This is the case with all social animals, at some point in the evolution of life on earth species started to realise that working together offered the greatest chance for survival, and if more of a species survive longer there are more offspring to reinforce the population leading to a trend in growth and higher and higher chances of survival for the species as a whole.

We have evolved not just to think about our own survival, but the survival of our own direct progeny and the survival of the species as a whole, and as such we instinctively seek ways we can maintain survival. Stopping violence, murder, stealing etc are just common sense ways of achieving all this.

Culture also evolves and that explains the difference in general moralities amongst different regions, races, religions and traditions in various times and places. The more isolated the communities become from each other the more different they become over time, due to independent emergences of cultural, political, historical and genetic events shaping opinion (Eastern and Western philosophy being examples of such) and thus the social moralities of different peoples changes.

If you believe it is moral to eat babies you can go and do it, but you'd better be ready to face the wrath of society if you do. As part of a society you have to live within it's rules, there are consequences from minor to major depending on the violation, you lose the privilege of being part of this group, either temporarily through prison or permanently through exile or death.