To incur an ontological commitment—that is, to be committed to the existence of a given object—a criterion for what exists needs to be satisfied. There are, of course, various possible criteria for what exists (such as causal efficacy, observability, possibility of detection, and so on). But the criterion Azzouni favors, and he takes it to be the one that has been collectively adopted, is ontological independence (2004, p. 99). What exist are the things that are ontologically independent of our linguistic practices and psychological processes. The point is that if we have just made something up through our linguistic practices or psychological processes, there's no need for us to be committed to the existence of the corresponding object. And typically, we would resist any such commitment.