Ethicists have tended to treat the psychology of attributing mental states to animals as an entirely separate issue from the moral importance of animals’ mental states. In this paper I bring these two issues together. I argue for two theses, one descriptive and one normative. The descriptive thesis holds that ordinary human agents use what are generally called phenomenal mental states (e.g., pain and other emotions) to assign moral considerability to animals. I examine recent empirical research on the attribution of phenomenal states and agential states (e.g., memory and intelligence) to argue that phenomenal mental states are the primary factor, psychologically, for judging an animal to be morally considerable. I further argue that, given the role of phenomenal states in assigning moral considerability, certain theories in animal ethics will meet significant psychological resistance. The normative thesis holds that ethicists must take the psychology of attributing mental states into account when constructing moral ideals concerning animals. I draw from the literature in political philosophy on ideal and non-ideal theory to argue that non-ideal theories for animals must account for human psychology because—like current social and political conditions—human psychology limits the achievement of moral ideals.