"act as a virtuous person would" is an empty statement.
It's an empty statement until you tack on a concrete description of virtue. But that's not hard to do. Aristotle, for instance, gives a long discussion about bravery and prudence and wisdom and justice and so forth in the Ethics -- and he does it without having a full account of what makes an action good or bad.
I suspect that what you are viewing as vacuous is really an implicit appeal to widely shared and widely understood norms that determine what makes people admirable or blameworthy.
You're concerned with actions that the person is predisposed to. The non-ethically-relevant action that you observe is still evidence that that person has a temperament that disposes them to ethically relevant and unfavourable actions.
Yes. But why is it easier to talk about good and bad actions than about good and bad temperaments? I agree there has to be a substantive account somewhere. But I don't actually know how to define utility in a moral sense, and it seems like a very hard problem. It's not pleasure or the emotion of happiness. When consequentialists start talking about "human flourishing," I feel like a virtue ethics is being smuggled in the back door.
But why is it easier to talk about good and bad actions than about good and bad temperaments?
I'm not saying one is easier than the other, I'm saying one is more fundamental than the other. Bravery is nothing but a disposition to actions, and prudence and wisdom, to the extent that they are not dispositions to actions, are not morally relevant. They're intellectual virtues, not moral virtues.
But I don't actually know how to define utility in a moral sense, and it seems like a very hard problem.
That's a completely different issue.
...When consequentiali
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?