Rationally Speaking

http://rationallyspeaking.blogspot.com/

My position is that morality in the modern sense is the result of a process of evolution favoring pro-social behavior (not "flourishing"), which we can trace to other species of primates, followed by millennia of self-reflection and discussion among human beings (i.e., cultural evolution, which doesn't enter into your scenario at all). As such, I think moral precepts are contingently (as opposed to absolutely) and non-arbitrarily (as opposed to "objectively") true. Neither of those two qualifiers comes even close to moral relativism. The contingency arises from the fact that morality makes sense only for certain types of intelligent, conscious, social animals, like us. If we were a radically different type of organism we may have developed different moral norms, or perhaps no morality at all. Non-arbitrariness separates morality from, say, rules of etiquette. But ethics is often an issue of balancing contrasting rights and alternative norms of behavior, so that there may be more than one reasonable way to address a particular moral problem, and none of the reasonable alternatives may be objectively better than another one.

---SPSmith