Am I frustrated or what. I've been having a back and forth over at Pharyngula about animal testing and the ethics thereof. What is frustrating is that these are people who are clearly intelligent and yet they refuse to even recognize the inconsistency in their positions. You can't simply say that empathy is the basis for morality, because it isn't. Empathy may be why we act in accordance with moral rules, why we generally don't kill people, but it isn't a reason in and of itself for something to be wrong or right. Trying to do this is what philosophers call naturalizing ethics or morality. I have a paper somewhere that makes a valiant attempt at this, but fails.
What it boils down to is what Hume called confusing the is-ought distinction, AKA the fact-value distinction. Just because something is doesn't mean it is right.