There is a growing consensus that the mind is neither constituted by nor identical with the brain. One reason why not is the mind's constitutive dependence on its environment, and especially on other people. My paper develops some ideas about the "other people" side of this story. I explore second-personality (and hence first-personality—I will explain this inference) as essential to mindedness as we know it. Following cues from Augustine, Wittgenstein, Sartre, and Stephen Darwall, I also suggest that second-personality has a key place in the foundations of ethics.