He subsequently worked at various universities in North America and Australia. In 1977 he became a professor of philosophy at Monash University, in Melbourne. Singer also became closely associated with the university's Centre for Human Bioethics, which is dedicated to the study of the moral implications of biomedical discoveries. He served as its director from 1987 to 1991 and as its deputy director from 1992. In 1999 he became a professor at Princeton University's Center for Human Values.
Singer is regarded as a rationalist.
He supports a philosophical system based on reason rather than on sentiment, self-interest, or social conditioning. He has taken a preference utilitarian approach to the ethical issues involved in embryo experimentation, genetic engineering, surrogate motherhood, abortion, and euthanasia. This approach regards an action as ethically correct if it satisfies the preference of those affected and has the best consequences for the greatest number of people. Singer also rejects the idea that killing is wrong regardless of the circumstances. Singer has published several books.