Singer's appointment as Ira W. DeCamp Professor of Bioethics at Princeton University's Center for Human Values in 1999 didn't go unnoticed. There were major protests from pro-lifers, from people with disabilities, even from ex-presidential hopeful Steve Forbes, of all people, who threatened to stop making donations to his former alma mater. Now, all the protesters are gone. The lectures by "Professor Death," as his critics like to call him, are not disrupted anymore. Actually, at a "practical ethics" class on a Monday morning not long ago, his students barely made a sound.

His ideas, however -- readily available to friends and enemies in the new anthology "Writings on an Ethical Life" -- have pretty much stayed the same. His central argument is elegant and simple; a child might have come up with it. Humans are animals, therefore animals are in the same league as humans, and should be treated as such. By attacking what he calls "speciesism," racism based on species instead of skin color, Singer raises the status of animals. (He is generally considered to be the founding father of the animal liberation movement and has turned quite a few meat eaters into vegetarians.) But, and this is the more controversial part, in raising the status of animals -- or nonhuman animals, as he calls them -- he effectively lowers the status of human beings, just as Charles Darwin did when he showed that all living beings are biologically related.

Moreover, Singer's utilitarian worldview, which defines good or bad by the pleasure or suffering it causes, leads him to believe that the life of a human being is not always sacred or worth living. Death is sometimes preferable to life. The 54-year-old philosopher from Melbourne maintains that the life of an infant is not automatically more valuable than the life of a higher animal, say a pig, especially not when that infant has all kinds of "defects." Parents should be allowed to have the life of a severely disabled baby ended, according to Singer, just as a pregnant woman is allowed to have an abortion when she discovers her embryo will become a disabled child.

Not even the Netherlands, the first country in the world to have officially legalized euthanasia, goes this far. According to Dutch law, the patient always has to be able to give informed consent to the active ending of his or her life. Infants (and "patients in a permanent vegetative state" or people with advanced Alzheimer's, among others) cannot give such consent. So helping them to die is murder.

As three of Singer's Jewish grandparents were killed by the Nazis when they were living in Austria (his parents fled to Australia in time), it is ironic, to put it mildly, that some of his fiercest critics in the U.S. and in Europe call him a Nazi. They think that when you accept Singer's views, the euthanasia program of the Third Reich, in which thousands of unwanted human beings were put to death, can't be far away. Salon interviewed Singer at Princeton University.

Do you still get hate mail or threats?

Threats, occasionally. By conservative Christians mostly.

Princeton University has always stood by you?

Yes. They've been very good.

Have you been enjoying it so far?

Very much.

Is there a lively discussion going on about the issues at the Center for Human Values?

Not until I came -- there wasn't anything going on. Now, you have Lee Silver, who is a molecular biologist, discussing a lot of bioethical issues, and Shirley Tilghman, who heads the National Center for Human Genome Research. We've been co-sponsoring lectures.

Are people in academia afraid to talk about your work?

There's a certain narrowness about discussion in America. If you go outside the bounds of that narrowness -- in different directions -- you get a not very tolerant response. It's not that people say, "I don't agree, it's poorly argued" or whatever. No, they jump up and down with placards, or write letters to the university president saying you should be dismissed.

Maya Angelou reads from "The Heart of a Woman"