The Edge of the Moral Circle

Abstract

This essay explores the relationship between two recent books on the scope of moral consideration: “The Edge of Sentience” (Birch 2024a) and “The Moral Circle” (Sebo 2025). Both books address the ethical and scientific challenge of determining how to interact with beings of uncertain sentience and moral status. They also argue for similar conclusions: they develop precautionary frameworks for guiding these decisions, and they argue that many invertebrates, future AI systems, and other beings merit moral consideration or, at least, further investigation. However, the books differ in focus and scope: “The Moral Circle” focuses more on ethical theory and long-term progress, while “The Edge of Sentience” focuses more on public policy and short-term progress. This essay highlights the complementary nature of these works and identifies key areas for further research, including how to navigate moral uncertainty and how to reconcile ethical principles with practical and political realities.