Moral circle expansion

Moral circle expansion is an increase over time in the number and type of entities given moral consideration. The general idea of moral inclusion was discussed by ancient philosophers and, since the 19th century, has inspired social movements related to human rights and animal rights. Especially in relation to animal rights, the philosopher Peter Singer has written about the subject since the 1970s. Since 2017, the Sentience Institute, a think tank associated with the 21st-century effective altruism movement, has also been actively engaging on this subject. There is significant debate on whether humanity actually has an expanding moral circle, considering topics such as the lack of a uniform border of growing moral consideration and the disconnect between people's moral attitudes and their behavior. Research into the phenomenon is ongoing.