 In meta-ethics, Lewis defended a variety of  subjectivism  (1989b). Like many subjectivists, Lewis held that something is valuable for us if and only if we would value it under ideal circumstances. And he held, following Frankfurt (1971), that valuing something is simply desiring to desire it. What is distinctive about Lewis’s position is his view about what ideal circumstances are. He thinks they are circumstances of “full imaginative acquaintance”. This has some interesting consequences. In particular, it allows Lewis to say that different goods have different conditions of full imaginative acquaintance. It might, he suggests, be impossible to properly imagine instantiating several different values at once. And that in turn lets him argue that his value pluralism is consistent with this kind of subjectivism, in a way that it might not be consistent with other varieties of subjectivism.