Abstract
Most people will grant that we bear special moral obligations toward at least some nonhuman animals that we do not bear toward inanimate objects like stones, mountains, or works of art. These moral obligations are plausibly grounded in the fact that many if not all nonhuman animals share important psychological states and capacities with us, such as consciousness, suffering, and goal-directed behavior. But which of these states and capacities are really critical for a creature’s possessing moral status, and how can we determine which animals do in fact have them? In this paper, I examine three main approaches to answering these questions. First are what I term consciousness-based approaches that tackles these questions by first asking which animals are conscious. Second are affective-state approaches that focus on identifying behavioural and physiological signatures of states like pain, fear, and stress. Finally, I consider what I call preference-based approaches whose focus is on the question of which organisms have robust motivational states. I examine the prospects and challenges—both theoretical and empirical—faced by these seemingly contrasting methodologies. I go on to suggest that there are reasons why, despite challenges, we should be robustly committed to the project of identifying psychological grounds of moral status. I conclude by suggesting we should also take seriously the idea of pluralism about moral status, according to which each of these approaches might be capable of providing independent grounds for moral consideration.