The question asks what makes another being’s welfare morally relevant. Sentience supplies a reason to consider suffering, while other approaches emphasize rights, capacities, or relationships. Equal consideration of comparable interests does not necessarily mean identical treatment of every species or a single rule for every conflict.
Different moral frameworks can agree that animal suffering matters while disagreeing about what follows. A welfare view weighs the seriousness of interests across affected beings; a rights view can place limits on using an animal even for benefit; a relational view may emphasize duties created by dependency and care. These approaches help separate three questions: whether an animal counts, how its interests compare with others’, and what forms of treatment are permissible.