  Metaethically, the Republic presupposes that there are objective facts concerning how one should live. Much of its account of these facts sounds naturalist. After all, Socrates uses the careful study of human psychology to reveal how our souls function well or ill, and he grounds the account of what a person should do in his understanding of good psychological functioning. Socrates’ particular deployment of this general strategy suggests that good actions are those that sustain the virtuous soul (443e) and that the virtuous soul is the one with a maximally unified set of commitments (443d–e, cf. 534b–c). Whether this is plausible depends upon what careful study of human psychology in fact shows. It depends in particular on whether, as a matter of fact, the actions that we would pre-theoretically deem good sustain a coherent set of psychological commitments and those that we would pre-theoretically deem bad are inconsistent with a coherent set of psychological commitments. Ethical naturalism such as this still awaits support from psychology, but it has not been falsified, either.