Quoting myself

A commenter on Roll to Disbelieve (a Patheos nonreligious blog I follow) has been contemplating ethics a lot lately, especially the idea that in an atheistic world ethics are subjective. As he put it:

The idea of subjective morality causes me to cringe: after all, if morality is subjective, what's wrong with oppression and Christian overreach? I would like to think that things like genocide and rape are wrong, period, no matter what one's subjective morality says.

Most of the commenters made arguments that morality has to be subjective, but I decided to be a contrarian:

I think it's likely that there is some ontological reality to ethics beyond human whim, and that this is consistent with the observation of altruistic behavior in non-human animals. The ethics that comes from that is likely fairly rudimentary and more descriptive than prescriptive, but there does seem to be a foundation for ethics that goes beyond social contract theory.

In other words, when we build ethics, we're not building it on something we made up but something built into our brains. However, if you want that foundation to be something that crosses the is/ought barrier, you're going to have to invoke the supernatural.