Peter Albert David Singer (born 6 July 1946) is an Australian moral philosopher. He is currently the Ira W. DeCamp Professor of Bioethics at Princeton University, and a Laureate Professor at the Centre for Applied Philosophy and Public Ethics at the University of Melbourne. He specialises in applied ethics and approaches ethical issues from a secular, preference utilitarian perspective. He is a major proponent of biocentrism (ethics). He is known in particular for his book, Animal Liberation (1975), a canonical text in animal rights/liberation theory.
On two occasions Singer served as chair of the philosophy department at Monash University, where he founded its Centre for Human Bioethics. In 1996 he stood unsuccessfully as a Greens candidate for the Australian Senate. In 2004 he was recognised as the Australian Humanist of the Year by the Council of Australian Humanist Societies, and in June 2012 was named a Companion of the Order of Australia for his services to philosophy and bioethics. He serves on the Advisory Board of Incentives for Global Health, the NGO formed to develop the Health Impact Fund proposal. He was voted one of Australia's ten most influential public intellectuals in 2006.