[AChimp]

Morality is just a set of behaviours that have been deemed acceptable and desirable by social norms that have evolved over time. What is moral for one group of people may not be moral for another; the only reason for this is differences in how various cultures have developed.

Part of the influence on this is religion, but "what's good for society to keep running" is also a major player in defining morality (even then, religion is just a tool for enforcing a prescribed set of social rules). It's not beneficial for a society to let people run around killing each other, hence why everyone thinks that killing people is wrong and the people who don't agree are labelled psychopaths. Wrap killing another person in the blanket of "self-defence" and suddenly it becomes acceptable, if not necessarily desirable.

Step back a few thousand years to gladiatorial fights, and suddenly killing people under a much wider set of circumstances is completely acceptable. I'm sure that there were a lot of Romans who thought that gladiators fighting each other to the death was "wrong," but they were the small minority and obviously didn't have much influence for a long time.

One hundred years ago it was considered immoral for women to wear pants, but I see a lot of women wearing pants nowadays. Are our morals sliding backwards into debauchery or are they just evolving with time as popular opinion changes?

Where does a universal concept of right and wrong fit in with stuff like that? It doesn't because if you're an atheist you think the universe is just a giant machine running on a defined set of physical rules. You cannot rationally define the concept of "good" and "evil" because everyone would have a different opinion on what constitutes each based on any number of social factors.

The way I see it, the morals we have now won't be the same as the morals we'll have in 1000 years. You'll see similarities, but there will probably be some pretty big differences.