Peter Singer

"It is now generally accepted that the roots of our ethics lie in patterns of behavior that evolved among our pre-human ancestors, the social mammals and that we retain within our biological nature ele…"

"The animals themselves are incapable of demanding their own liberation, or of protesting against their condition with votes, demonstrations, or boycotts. Human beings have the power to continue to opp…"

"Science does not stand still, and neither does philosophy, although the latter has a tendency to walk in circles."

"The principles of ethics come from our own nature as social, reasoning beings."

"When my ability to reason shows me that the suffering of another being is very similar to my own suffering and matters just as much to that other being as my own suffering matters to me, then my reaso…"

"The only justifiable stopping place for for the expansion of altruism is the point at which all whose welfare can be affected by our actions are included within the circle of altruism. This means that…"

"Human beings are social animals. We were social before we were human."

"If evolution is a struggle for survival, why hasn't it ruthlessly eliminated altruists, who seem to increase another's prospects of survival at the cost of their own?"