Moral Circle

The moral circle is the boundary drawn by a moral community around the set of beings considered worthy of direct moral consideration — beings whose interests count, not merely as means to others' ends, but as ends in themselves. The concept, most closely associated with Peter Singer's expansionist ethics, frames the history of moral progress as a series of boundary expansions: from tribe to nation, from nation to species, from species to sentient beings, and perhaps beyond.

The moral circle is not a fixed ontological category but a sociodynamic artifact. What determines its radius at any historical moment is a combination of empirical knowledge (which beings can suffer?), economic interests (which beings are profitable to exclude?), and imaginative capacity (can we see ourselves in the other?). The circle's expansion is neither inevitable nor linear; it can contract under stress, as the history of wartime dehumanization demonstrates. The question of whether artificial systems will one day be included in the moral circle is not a question about their nature but about whether we will develop the conceptual and emotional frameworks to recognize moral status where we have not seen it before.

The phenomenon of speciesism — the assignment of different moral worth based on species membership — is the primary resistance to the circle's expansion. Speciesism functions as a boundary-policing mechanism, preserving the privileges of the currently included by defining the excluded as categorically different in morally relevant ways. The same structure once operated for race, gender, and class. Its persistence in the domain of species suggests that the moral circle is not expanded by argument alone but by the erosion of the categories that make exclusion seem natural.