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.
Perhaps you could explain?
You claim to not ascribe moral valence to societies, and then promptly proceed to declare a social system "barbaric".
But I haven't found any suggestions that people are evolving in any ways that would change the moral weight we should assign individuals.
I didn't say anything about moral weight, largely because I've never heard a good explanation of how it is supposed to be assigned. I'm talking about their cognitive abilities, in particular their ability to act sufficiently morally.
I don't think so, but I'm not exactly sure why you say that. From a consequentialist perspective, if people have the cognitive ability to understand moral thought, then the outcome of trying to convince them that they should use it in a particular way can be a net benefit and thus morally correct. [emphasis mine]
That's deontological reasoning (there is a chance these people can be saved, thus it is our duty to try). Consequentialist reasoning would focus on how likely the attempt is to succeed and what the consequences of failure would be, not just whether they can be saved.
You claim to not ascribe moral valence to societies, and then promptly proceed to declare a social system "barbaric".
Fair enough. One difficulty of consequentialism is that unpacking it into English can be either difficult or excessively verbose. The reason Star Trek style social Darwinism is barbaric is because of its consequences (death of billions), not because it violates a moral rule that I have regarding social Darwinism. If it worked, then that would be fine.
...Consequentialist reasoning would focus on how likely the attempt is to succee
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?