The expanding circle

In 'The Expanding Circle', Peter Singer integrates insights from sociobiology and ethics to argue that human altruism, initially driven by genetic instincts to protect kin and community, has evolved into a consciously chosen ethic with an expanding circle of moral concern.

Singer contends that our capacity for reason allows us to extend moral consideration beyond biological and social groups to include all beings capable of feeling pleasure or pain.

The book discusses the relationship between reason, ethics, and the biological basis of human behavior, and it includes a new afterword in the 2011 edition that reflects on recent research in the field.