Forthcoming in Cambridge Dictionary of Philosophy 3 rd edition. Singer, Peter (b.1946) Australian moral philosopher notable for his role in the emergence of applied ethics in the second half of the twentieth century and for his systematic application and defense of utilitarianism. Singer has made major philosophical contributions to discourses on animal welfare, bioethics, and global poverty; he is often referred to as the father of the modern animal rights movement. Singer's Animal Liberation (1975, 2009) introduced factory farming and animal experimentation as moral problems to a new generation of philosophers and social activists. For most of his career Singer's published work has reflected sympathy with his Oxford mentor R.M. Hare's (1919-2002) formulation of preference utilitarianism. In Practical Ethics (1979, 2011), Singer argues that taking ethics seriously necessarily entails the equal consideration of other sentient beings. Singer identifies this minimal ethical starting point with utilitarianism and in particular with preference utilitarianism. Singer has followed Hare in defending a preference utilitarianism that recommends-all things being equal-the maximum preference satisfactions of morally relevant beings. In order to have a preference, one must be capable of suffering. Therefore, Singer argues, the minimal moral universalization inherent in ethics demands that equal consideration of interests be given to all beings with a preference (not to suffer), which is to say, to all sentient beings. Recently Singer has become more sympathetic to the possibility of objective reasons for ethical actions, in accordance with hedonistic utilitarianism (Practical Ethics, 2011). Singer's writings on global poverty and animal welfare are compatible with both forms of utilitarianism. Singer argues that the seriousness of our ethical responsibility to aid strangers suffering from absolute poverty is no less than our responsibility to aid those suffering closer to home (The Life You Can Save, 2009). From the universal perspective of morality, neither species membership nor geographic distances are significant. Singer explores the universalizing nature of ethics and its relationship to evolution in The Expanding Circle (1983, 2011). He presents his views on the ethics of globalization, international law, and climate change in One World (2002). Singer's prominent work on bioethical issues appears in numerous articles and books, including Practical Ethics and Should the Baby Live? (with Helga Kuhse, 1985). Singer is Ira W. DeCamp Professor of Bioethics at Princeton University and Laureate Professor at the University of Melbourne.