Animal Welfare and the Expanding Moral Circle

The expanding moral circle concept describes the historical and ongoing process by which ethical concern extends to previously excluded groups, with animals at the current frontier of this moral expansion.

Key Facts

Philosopher Peter Singer popularised the expanding circle concept in his 1981 book The Expanding Circle
Historical expansions of the moral circle have included women, enslaved people, and people of different ethnic groups
The expanding circle now includes movements to extend moral consideration to animals, future generations and potentially AI systems
Peter Singer and Paul Bloom have debated whether the expansion of concern reflects emotional or rational processes
The Animal Sentience Act 2022 embedding vertebrate sentience in UK law represents a legislative expression of moral circle expansion

Welfare Considerations

Understanding the expanding moral circle provides historical perspective on animal welfare advocacy. Previous exclusions from moral consideration — of women, enslaved people, or people of other nations — were once defended by mainstream opinion and are now recognised as moral failures. The exclusion of animals from moral consideration is increasingly being questioned through the same combination of philosophical argument, scientific evidence about shared characteristics, and cultural change that drove previous expansions. The pace of moral circle expansion for animals is uncertain but the direction is consistent with historical patterns. Animal welfare advocates who understand this historical context can draw on it to make more compelling arguments for reform to audiences who have not yet considered the parallels.

What You Can Do

Read Peter Singer The Expanding Circle or Animal Liberation for the philosophical foundations of moral circle expansion
Engage with the historical parallel between animal welfare and other civil rights movements when appropriate in advocacy
Support organisations working to expand legal recognition of animal interests through law reform
Participate in public discussions about animal moral status using evidence about sentience and capacity for suffering
Build coalitions with other rights-based movements that share the principle of expanding consideration to excluded groups