I have a homosexual question and incest question?

[Jenny A]

At some level most of our moral decisions are like this. They are based on emotions. They we look for reasons whether rational or religious.

This reminds me of arguments against meat-eating based on empathy. We have empathy for creatures with awareness, and that's a good thing, as it prevents us treating other humans cruelly without remorse. But there's some question as to whether those feelings of empathy should be sanctioned when they are extended beyond the obvious role of protecting fellow humans. So we may want to encourage broad empathy for the positive effect it has on the way humans treat each other, and just accept any possible "over-extension" of that empathy beyond the human sphere by extending rights to animals, even if doing so is something of a moral accident.

Similarly, we want to discourage incest because of its negative effects "in general," and we've evolved feelings which support that goal as a consequence of evolution. Should we attempt to fine-tune the application of those moral intuitions as in the cases given above, or should we opt for uniformity to keep the moral intuition against incest strong and inviolate? Should we accept a few "useless applications" of rules that are generally good, or should we seek to make exceptions to the rule in cases of clear misapplication?

Of course we should attempt to fine-tune our moral intuitions. The point is that it's difficult to do in practice because our emotions get there first. Knowing that helps, but it's not a panacea.