Depending on whom you believe Peter Singer could be “the most dangerous man on earth” or “one of the world’s 100 most influential people.”

Either way, the Australian-born ethicist and moral philosopher can now add to the list Companion of the Order of Australia (AC), the highest civilian honor bestowed by the nation.

The Melbourne-raised professor of bioethics at Princeton University was awarded the accolade last week in the annual Queen’s birthday honors list.

Loved and loathed, divisive and incisive, one thing about Singer cannot be refuted: He is an intellectual giant who has provoked debate about critical – and sometimes controversial – issues of humanity, including abortion, infanticide, euthanasia, eugenics and animal rights.

Singer, who lost three of his grandparents in the Holocaust, has also stirred debate on several issues that affect Jews and Israel.

“Clearly, there were moral flaws in the setting up of the State of Israel without proper consultation and participation by Palestinians,” he told Haaretz this week. “But that was a long time ago now, and I think that instead of looking backwards, we should try to work out the best solution for all those living in Israel and the occupied territories.”

He has occasionally ventured from academia into activism, signing a petition in 2010 renouncing his “right of return” to Israel because it is “a form of racist privilege that abets the colonial oppression of the Palestinians.”

“It is not right that we may ‘return’ to a state that is not ours while Palestinians are excluded and continuously dispossessed,” the petition stated.

Equally, Singer has irked Orthodox Jews, opposing ritual slaughter since the 1970s, when he wrote “Animal Liberation,” which catapulted the issue of animal rights from the sidelines to the headlines.

“Even when shechita [the Jewish method of slaughter] is at its best, it is still less humane than modern slaughter, properly done,” says Singer, who has been a vegetarian since 1971.

“No one has the right to inflict needless suffering on another sentient being," he says. "And this is needless, because no one with access to a wide range of food needs to eat meat.”

A staunch promoter of freedom of speech, Singer has also defended proponents of Holocaust revisionism, such as David Irving’s “absurd” opinions.

“If there are still people crazy enough to deny that the Holocaust occurred, will they be persuaded by imprisoning people who express that view,” he asked in 2006 when Irving was jailed in Austria for Holocaust denial.

“On the contrary, they will be more likely to think that people are being imprisoned for expressing views that cannot be refuted by evidence and argument alone.”
And yet some critics allege his theories are reminiscent of Nazism, with one labeling his 1995 book “Rethinking Life and Death” as “the 'Mein Kampf' of the euthanasia movement.”

Singer, a utilitarian, supports legal reform to allow terminally ill people to end their lives. He also argues that a seriously disabled baby should actively and humanely have its life terminated if the parents and a doctor decide – and not just by withholding or withdrawing life support, which can lead to a slow and inhumane death.

"Killing a defective infant is not morally equivalent to killing a person," he wrote, although he notes that by "person" he means someone who can anticipate the future. "Sometimes it is not wrong at all."

This provoked a firestorm of protest from pro-life activists, among them Diane Coleman, the founder of Not Dead Yet, a U.S.-based disability group that opposes euthanasia, who called Singer "the most dangerous man on earth."

Singer says of critics who use the "Nazi" label: “It’s absurd and it makes me sad,” adding that it “devalues the atrocities that the Nazis committed.”

His latest crusade, however, is global poverty, which he argues can be substantially alleviated, if not entirely eradicated, by philanthropy.

In “The Life You Can Save,” he proposes a sliding scale commensurate with income; but rather than the biblical tithe, most people in the developed world should donate 5 percent and the affluent much more. He donates 25 percent of his income to NGOs, mostly to help combat global poverty.

Although his family has a Passover Seder – “with a beetroot instead of a lamb shank” – and he celebrates Purim with his grandchildren as well as Rosh Hashanah, Singer says Jewish traditions “did not play much of a role in my life.”

But he accepts that his family history did play a part in the development of his theories. “As three of my grandparents died in the Holocaust, and the fourth was fortunate to survive in Theresienstadt, that was very much present in my life,” he says.

“I am sure that it had some impact on my thought – on my abhorrence of cruelty, of the naked use of power over the defenseless, and of course of racism.”

His family background also informed his view on religion at a young age. His parents gave him the choice of whether to have a bar mitzvah; he declined.

“It always seemed to me wildly implausible that a god worth worshipping could allow the Holocaust to occur,” he says.

So how does the 65-year-old professor feel about having received the equivalent of the Israel Prize or the U.S. Presidential Medal of Freedom?

“It shows you don’t have to be a conformist to be recognized by your country,” Singer says. “And it demonstrates the value of admitting refugees, like my parents, to Australia – either they or their children and grandchildren are contributing.”