When philosopher Simon Blackburn was invited to present a lecture on one of the Seven Deadly Sins, he feared he would be asked to address sloth. "I did worry," he said, "not because of unfamiliarity with the vice, but because of doubts about having the energy to find something to say about it."

As it turned out, Blackburn was not invited to speak about sloth. Instead, he was invited to address the issue of lust, and on that topic he found enough energy to say a good deal about a vice that has driven humanity throughout the ages.

Lust, Blackburn argues, "gets a bad press." His project, based on his lecture sponsored by the New York Public Library and Oxford University Press, is to rescue lust from misunderstandings and historical abuse. He does acknowledge that lust has a bad reputation. "It's the fly in the ointment, the black sheep of the family, the ill-bread, trashy cousin of upstanding members like love and friendship. It lives on the wrong side of the tracks, lumbers around elbowing its way into too much of our lives, and blushes when it comes into company."

Blackburn is a philosopher of wide reputation who has taught at the University of North Carolina, Oxford University, and the University of Cambridge. He is an excellent writer who combines both style and wit. In recent years, he has written Think and Being Good, two works intended to introduce philosophical subjects to a general readership. In those books, Blackburn presents a fundamentally secular understanding of life and a rather dispassionate engagement with philosophical and moral issues.

In his new book, Lust, Blackburn presents an updated vision of lust as sexual desire for its own sake. If lust now has a bad press, Blackburn wants to be its public relations agent.

Lust is inevitably compared with love. Blackburn understands the quandary, noting: "We smile at lovers holding hands in the park. But we wrinkle our noses if we find them acting out their lust under the bushes. Love receives the world's applause. Lust is furtive, ashamed, and embarrassed. Love pursues the good of the other, with self-control, concern, reason, and patience. Lust pursues its own gratification, headlong, impatient of any control, immune to reason."

As a moral philosopher, Blackburn understands that love requires knowledge, reason, and time, combined with truth and trust. Lust, on the other hand, is symbolized by "a trail of clothing in the hallway" that represents a loss of reason, self-control and discipline.

Needless to say, lust has been a part of human desire and human experience ever since the Fall. Blackburn, who provides no evidence of even believing in anything like sin, sees lust as one of the greatest moral challenges facing modern individuals. "Living with lust," he says, "is like living shackled to a lunatic." Frankly, it's hard to improve upon that description.

Much of the difficulty in addressing the issue of lust in our modern times can be traced to the highly sexualized character of contemporary culture. Even if lust is reducible to sexual desire (rather than desire for power, money, or other goods), it is increasingly difficult to separate lust from the ordering of everyday life. Sex has lost its public shamefulness, moral boundaries have been pulled down in the name of moral "progress," and overt sexuality now drives much of our entertainment, advertising, and cultural conversation. How is lust to be separated from all that?