How significant is the influence of Princeton philosopher Peter Singer? Marvin Olasky writes:

The New York Times, explaining how his views trickle down through media and academia to the general populace, noted that "no other living philosopher has had this kind of influence." The New England Journal of Medicine said he has had "more success in effecting changes in acceptable behavior" than any philosopher since Bertrand Russell. The New Yorker called him the "most influential" philosopher alive.

Don't expect Peter Singer to be quoted heavily on the issue that roiled the November 2, 2004 election, same-sex marriage. That for him is intellectual child's play, already logically decided, and it's time to move on to polyamory. While politicians debate the definition of marriage between two people, Mr. Singer argues that any kind of "fully consensual" sexual behavior involving two people or 200 is ethically fine.

For example, when I asked him last month about necrophilia (what if two people make an agreement that whoever lives longest can have sexual relations with the corpse of the person who dies first?), he said, "There's no moral problem with that." Concerning bestiality (should people have sex with animals, seen as willing participants?), he responded, "I would ask, 'What's holding you back from a more fulfilling relationship?' [But] it's not wrong inherently in a moral sense."

If the 21st century becomes a Singer century, we will also see legal infanticide of born children who are ill or who have ill older siblings in need of their body parts. Question: What about parents conceiving and giving birth to a child specifically to kill him, take his organs, and transplant them into their ill older children? Mr. Singer: "It's difficult to warm to parents who can take such a detached view, [but] they're not doing something really wrong in itself." Is there anything wrong with a society in which children are bred for spare parts on a massive scale? "No."

When we had lunch a month after our initial interview and I read back his answers to him, he said he would be "concerned about a society where the role of some women was to breed children for that purpose," but he stood by his statements. He also reaffirmed that it would be ethically okay to kill 1-year-olds with physical or mental disabilities, although ideally the question of infanticide would be "raised as soon as possible after birth."

These proposals are biblically and historically monstrous, but Mr. Singer is a soft-spoken Princeton professor. Whittaker Chambers a half-century ago wrote, "Man without God is a beast, and never more beastly than when he is most intelligent about his beastliness," but part of Mr. Singer's effectiveness in teaching "Practical Ethics" to Princeton undergraduates is that he does not come across personally as beastly.