The "Evils" of Moral Relativism

This is a topic which came up last night at an Atheist Society event. Somebody in the audience asked that old favourite question, which I shall paraphrase here:

"If you don't believe in god(s), then where do your morals come from? Why don't you just go around killing and raping each other?"

My initial reaction to this question is usually one of incredulity, rapidly followed by hope that the questioner really doesn't mean what they are suggesting. It keeps coming up though; people keep asking it and then waiting with that smug expression on their faces for the inevitable admission that all atheists are entirely devoid or morals, or that like Prometheus we 'borrowed' what we needed from the gods without acknowledging them. Or even sending a thank-you card. Godless heathens that we are!

What the question itself seems to suggest is that before religion came along, we did just go around murdering and raping each other. That, as Moses trudged down from Sinai, commandments fresh of the presses, everyone was busy coveting their neighbour's ass and killing and thieving and raping their little hearts out.

So Moses stands up and, after clearing his throat really loudly to distract them from their rampant sinning, reads out his ten simple rules. And after that, everyone is all about peace, love and understanding.

Given that we evolved as a social species, it seems far more likely that morals evolved along with us. That in order for us to exist in a tribe we had to follow certain rules of engagement. We didn't kill our fellow tribe-members and we didn't steal from them, because doing so would destroy the harmony of the group. Observation of other primates shows this kind of behaviour, whilst it has also been shown that they understand the concept of 'fairness' on an instinctive level.

Even disregarding other species and considering modern humans as we are now, one can derive a perfectly functional set of morals from the simple idea of doing unto others as you would have done to yourself. You don't kill because you wouldn't want to be killed, and likewise with theft, rape and so forth. It benefits the species if we help our fellow people, rather than fighting them.

In addition to this, deriving your morals from personal experience and not from a list of absolutes allows you to be more flexible in determining the morality of a given act. It is not always wrong to lie, most of us tell small lies all the time in order to avoid offending people, or to avoid recrimination. It is not always wrong to kill, although it nearly always is. There are scenarios in which killing one person is the more moral option, however distasteful this may seem. This does not lead to the collapse of society, however much the faithful say it will.

And finally, onto the big one, the best response I think you can give to that stupid question:

"Are you saying, then, that without a god or gods to watch you and punish you when you transgressed, you would be raping and murdering and stealing? Is it that these things are so fundamentally enjoyable that divine retribution is the only thing that will stop you?"

By placing the responsibility for morals on a higher authority, they abdicate all responsibility for thinking or caring about other people. They pass the buck. And by living by absolutes they miss out on a huge range of human moral experience.