I don't ascribe moral valence to societies, but to individuals, which is why I think this sort of social Darwinism is nothing short of barbaric.
Reread that sentence. Notice how the second half seems to contradict the first.
We already know from real life that there is no significant biological evolution after humans developed mature civilizations,
We do? This is not at all obvious. Consider the generic changes in domestic animals, for example.
If these people are biologically capable of advanced moral thought, that capability exists whether they are currently exercising it or not.
Note that the above sentence implicitly uses deontological reasoning.
Reread that sentence. Notice how the second half seems to contradict the first.
Perhaps you could explain? Social Darwinism in Earth terms seems to be the idea of "survival of the fittest" individuals within a society, but here I'm referring to a Star Trek variant of social Darwinism that occurs at the level of the society (similar to some definitions of social Darwinism described on the Wikipedia page, e.g. under the first Nazism header). The reason I call it social Darwinism rather than merely evolution is because in-fiction it occurs due to ...
Disclaimer: I am not a philosopher, so this post will likely seem amateurish to the subject matter experts.
LW is big on consequentialism, utilitarianism and other quantifiable ethics one can potentially program into a computer to make it provably friendly. However, I posit that most of us intuitively use virtue ethics, and not deontology or consequentialism. In other words, when judging one's actions we intuitively value the person's motivations over the rules they follow or the consequences of said actions. We may reevaluate our judgment later, based on laws and/or actual or expected usefulness, but the initial impulse still remains, even if overridden. To quote Casimir de Montrond, "Mistrust first impulses; they are nearly always good" (the quote is usually misattributed to Talleyrand).
Some examples:
I am not sure how to classify religious fanaticism (or other bigotry), but it seems to require a heavy dose of virtue ethics (feeling righteous), in addition to following the (deontological) tenets of whichever belief, with some consequentialism (for the greater good) mixed in.
When I try to introspect my own moral decisions (like whether to tell the truth, or to cheat on a test, or to drive over the speed limit), I can usually find a grain of virtue ethics inside. It might be followed or overridden, sometimes habitually, but it is always there. Can you?