Peter Singer is an Australian philosopher widely regarded as one of the most influential living philosophers, particularly for his contributions to the animal liberation movement. Born in Melbourne to parents who fled the German annexation of Austria, Singer was educated at Preshil and Scotch College. He studied law, history, and philosophy at the University of Melbourne, and earned his B.Phil. from Oxford in 1971.
Singer's master's thesis was entitled, "Why Should I Be Good?" In his touchstone work, Animal Liberation, Singer expanded on the question, arguing that the only measure of morality is the greatest good for the greatest number, popularizing the term "speciesism" as the practice of preferring humans over other animals. Other works, such as Practice Ethics, develop his ethical standpoint, the preference utilitarian perspective.