Certain things seem to be largely considered universally wrong. Other things have a lesser wrongness, a subjective wrongness, it seems.
Absolute Moral: Killing children is bad. We regard anyone who does it deliberately as sick and unfit for our society. It is appalling on a pretty deep level.
Subjective Moral: Living together before marriage. All of the arguments about this one involve assumptions that are not expected to be universally accepted, usually an appeal to some theology. This seems to be an intellectual sort of moral judgment rather than an intuitive one.
Absolute Moral: It is good to be kind to people. We feel that this is right by virtue of the pleasure we derive not only by having it done for us, but also by doing it for others.
Subjective Moral: It is good to read the Bible every day. Once again, an intellectual sort of judgment dependent upon one's personal opinions and worldview.
This distinction is known to most people. I mean... as a child, a Mormon may condemn anyone who drinks coffee or alcohol. Adults will find this amusing, because they know better: this little piece of morality is subject to assumptions that people do not have to make in order to still be considered moral. Even if those people are wrong wrong wrong, they are simply misled, not bad.
If you happen to belong to a cult that regards random murder as awesome, very few people are probably going to give you the same benefit of the doubt.
This whole idea occurred to me recently while I read part of a talk by Boyd Packer. He was talking about the sanctity of marriage. Nothing he said was what would be considered an appeal to absolute morality... it was all subjective, all dependent on Mormon theology. No one who didn't belong to the minority he belongs to could be persuaded in the least by his arguments.
I don't know that there is something innate or biological about this "absolute" morality.. I'm sure it's subject to culture as well. However, even if these rules are not technically "absolute," it seems that they are absolute as far as anyone from the society we inhabit is concerned. They certainly seem absolute relative to the "subjective" rules accepted only by this minority or that.
And so we get the following:
Atheist: Homosexuality = Okay, Killing = Not Okay
Mormon: Homosexuality = Not Okay, Killing = Not Okay
Can you think of a group that finds homosexuality okay and killing okay? If there is such a group, they will not be accepted as even roughly moral people by society. They will be locked away or killed.
"Absolute" morals ought to be reflected in law. "Subjective" morals probably shouldn't be in most cases.
Not to say that the prevailing morality is necessarily right, but it certainly is widely-held, and what else do we have?