This topic seems to cross my mind somewhat often. I feel that if anyone is ethical, and considerate of what that is and what it means, eventually they would have to consider that it really has nothing to do with what one is choosing or what a group of human beings might opt for evolutionarily speaking to perpetuate the species.
Of course, one does indeed consider ethics on this evolution airy type of cost benefit scale, but then I think someone would ultimately have to consider how it is very interesting that human beings would come up with a theory of ethics that is beneficial. That is, that it is quite a redundant proposal.
It would seem from this very simple consideration that there is nothing about ethics that is coming about because it’s beneficial to our species. Rather, it seems that ethics is some thing that we use to justify our existence and our activity more than really something that we use to make decisions upon. Of course, we make decisions, and of course we would call these decisions ethical and we can come up with all sorts of theories about it.
However, if we think of ethics as something that indeed arises in the universe as such, we might be obliged to think of it as a force that is occurring in which human beings are involved, but not necessarily creating, which is to say, as though ex Nilo. Or however you spell that.
We might consider that ethics arises as a logistical solution to existential problems. For example; it is not just that individuals identify with a cultural group and so see Other as a threat, as an evolutionary reductionary force Rather, that the Other never disappears, and so the very sense of ethical threat is an operation of ideological consolidation of Other, inclusion, a compensation for the contradiction that is arising in the ideal of a cultural/ religious ethics. That is, that no matter how we might wish or work to destroy the Other, it persists as a force that must be dealt with in a non contradictory manner.