Truth be told, Barash's line of inquiry, like Richard Dawkins' or Steven Pinker's, does result in bracing and unsettling ideas. Through the lens of evolutionary psychology, we are forced to face our ancient self, that bestial creature that knows nothing of atomic bombs or jihad, marriage or MySpace, but still haunts our body, fuels our emotions and rules our lives — our genetic identity. For this single-minded creature, monogamy is a myth, free will is doubtful, and so-called altruism is merely a misguided attempt to protect people who might be carrying our genes. (Since humans once lived in small, closely related packs, protecting others made genetic sense.) In a recent article for The Chronicle of Higher Education, Barash wrote about how electrocuted rats develop ulcers and swollen adrenal glands unless they are allowed to fight other "innocent" rats. In short: Random acts of violence are never actually random; we are merely obeying a million-year-old code of behavior, a code of displaced aggression that Barash finds in The Iliad, in Sweeney Todd and in our current war in Iraq. Barash's latest book, Natural Selections, published by Bellevue Literary Press (a small press run out of the oldest public hospital in the United States, Bellevue in Manhattan), seeks to follow the concepts of evolutionary psychology and sociobiology to their logical conclusions. "Many people claim to accept the tenets of evolution," he says, "but few actually look at where these premises lead."

I talked with Barash by phone about his book, his science and his philosophy.