At least two other scholars in this field have turned down Harvard tenure offers in the past several years, and Scanlon says his decision to accept was difficult. "Princeton has a very good Philosophy Department, but this one is also very good," Scanlon says, adding that what finally swayed him was the change of scene from New Jersey: "I've been talking and arguing with this group of people for 18 years."

When Scanlon joined the Princeton department in 1966, after earning his B.A. at Princeton and his Ph.D. at Harvard, he was a young mathematical philosopher with a background in logic. Sometime after 1974, when he co-authored a paper with Goldfarb, Scanlon switched to the field of moral philosophy. Already, though, Scanlon had expressed an interest in such questions of ethics as freedom of expression.

In 1972, he wrote the first of two articles on the topic, arguing that certain inflammatory statements, even if they led to harm, cannot be suppressed, because the speaker's "contribution to the genesis of the harmful act was superseded by the agent's own judgment."

The 1972 article led to what appears to be a running intellectual feud with Nozick, who in his 1974 book "Anarchy, State, and Utopia" called Scanlon's theory "mistaken."

"Though Nozick does not mention Scanlon by name," wrote a third-party philosopher, "I think it is clear from the context that he is responding to Scanlon's essay."

In a 1976 article on Nozick's book, Scanlon praised Nozick for bringing economic insituations to the same philosophical level as political institutions and political liberties, but criticized him for how he did his analysis.

"I have argued that the particular framework of property and contract rights which Nozick proposes does not constitute an adequate account of the claims of economic liberty," he wrote.

So how does is feel to be on the same Faculty as Nozick and other "gods" of the philosophy world? "They aren't the only gods," Scanlon says. "The gods are scattered around."