Interspecies Welfare Comparisons

ABSTRACT Interspecies welfare comparisons—judgments about whether one individual of a given species is better or worse off than another of a different species—are behind a wide range of moral and practical decisions. However, it remains unclear how to make such comparisons. This paper surveys the emerging literature on this problem. It distinguishes interspecies comparisons from related questions about individual welfare assessment and normative weighting, presents a simple model for extending welfare comparisons across species, and clarifies the problem of identifying appropriate comparative scales. It also examines proposals for estimating relative welfare ranges. The paper closes by highlighting the conceptual and practical challenges that remain and outlining ways philosophers can contribute to building a coherent, interdisciplinary framework for comparing welfare across species.