One of the most controversial and influential philosophers alive today, Peter Singer is DeCamp Professor of Bioethics at Princeton University, and laureate professor at the Centre for Applied Philosophy and Public Ethics, University of Melbourne. He writes a regular column for Free Inquiry magazine, and is the author of dozens of books, including Practical Ethics, Rethinking Life and Death, Animal Liberation, and Writings on an Ethical Life. In this discussion with D.J. Grothe, Peter Singer defends vegetarianism, arguing that we should give equal consideration to all "beings who have interests." He draws ethical distinctions between human fetuses and animals, such as dogs and cats. He argues against "dominionism," which is the idea that humanity is special, and that other animals were made by God for humanity's benefit. He attacks "speciesism," and explains why he did not sign the Humanist Manifesto 2000. He describes factory farming, and the commercial imperatives that he says cause animals to be treated as mere property. He talks about the decision to become a vegetarian, and what keeps secularists and scientists from making the decision, in terms of the question he posed to Richard Dawkins at a recent Center for Inquiry conference. And he considers how working with the religious may advance vegetarianism in society.