Singer (1946–) has at times argued that the lives of healthy, adult animals are of greater value than those of severely impaired human infants. Such views have met with great controversy. When Singer was hired by Princeton University in 1999, there were dramatic public demonstrations by and for disabled people, and the university administration hired armed guards to protect him.

Singer, proceeding on utilitarian grounds, does not believe that animals have rights, but rather that their well-being is intrinsically good and their pain and destruction intrinsically bad. Singer is not a deep ecologist, because he does not attribute intrinsic value to the well-being of mountains, rivers, or plants, or whatever is not sentient. Singer has claimed that the privileging of human life and well-being over that of animals is speciesism, which, in principle, is no different from racism and sexism.