Religions that have allowed themselves to be modified by secular knowledge downplay orthodox ideas of heaven and hell for the very good reason that such beliefs have been used throughout history to justify the most evil earthly acts imaginable. Christians slaughtered Jews and Muslims during the Crusades precisely because they believed that they were earning themselves a place in an all-Christian heaven, hemmed in by restrictive covenants.

In recent years, radical Islamists have embarked on suicide murder missions with the absolute conviction that they will be rewarded with a place in a Muslim paradise. The 60 percent of Muslim Americans who, according to a recent Pew Poll, do not accept the fact that the 9/11 terrorist attacks were carried out by Muslim Arabs, are deluded. Like the Christian Crusades, Islamist terror attacks are deeply involved with a form of religion that forsees an eternal reward for dastardly crimes against humanity.

I know that indignant readers will claim that none of these crimes have anything to do with the "real" Christianity or the "real" Islam. They don't have anything to do with modern, moderate forms of Christianity or Islam, but they have everything to do with retrograde expressions of religions that preach, among other things, the doctrine of eternal damnation for unbelievers and infidels. And these retrograde religious forms are on the rise in the world. They are every bit as "real" as religion based on earthly, loving kindness--something that promoters of religion as an unqualified good never want to admit.

Fear of hell has also proved notably inefficacious as a deterrent to evil human impulses; that is why we have man-made laws. Fundamentalists who want to post the Ten Commandments in courthouses have everything backward: we need courthouses precisely because some people just won't obey moral commandments unless they are subjected to earthly punishment.

In our godly nation, the most recent Gallup Poll (released on June 13, 2007) found that while 81 per cent of Americans believe in heaven, only 69 percent believe in hell. Approximately 86 per cent of American adults believe in God, but only 70 percent believe in the devil. We Americans really do like to have our cake (whether angel or devil's food) and eat it too; we seem to prefer the pursuit of happiness to the right to go to hell in our own way.

Because I am an atheist (and by the way, the percentage of Americans who believe in God has dropped by four percentage points--down from 90 percent to a minuscule 86 percent--during the past four years), I naturally do not believe in immortality in either heaven or hell. I say with Milton:

O Earth, how like to Heav'n, if not preferr'd
More justly, Seat worthier of Gods, as built
With second thoughts, reforming what was old:
For what God after better worse would build? (Paradise Lost, IX.100)

If I were a believer, though, I would definitely reserve my closest scrutiny for the devil's many earthly workshops, from the office of the current U.S. Vice President (described in such riveting infernal detail in the Post series on Dick Cheney this week) to the hellish refugee camps in Darfur.

There is a devil--not a supernatural being but the sum of the worst human impulses. The devil is in us. Or rather, the devil is us. And what so many people think of as a supernatural being called "God" can be understood in the natural realm as the human capacity for good.

I also reject the concept of limbo, and I send my kudos to the Vatican for finally changing its dogma that unbaptized infants can't go to heaven because someone didn't sprinkle water over their heads. This change truly epitomizes the Roman Catholic Church's commitment to dealing with humankind's most important problems. I am sure that every lunatic who actually believed in a deity cruel enough to deny his presence to sinless infants will be greatly relieved by the Church's change of heart.

But I certainly do believe in purgatory. Purgatory is wondering whether the human race in general, and my fellow Americans in particular, will ever grow up enough to realize that we ought to treat one another decently simply because of our common humanity--not because we are looking forward to being entertained by harpists among the clouds or are terrified of eternal flame.

Modern forms of religion tend to define heaven and hell in a somewhat abstract way--the former as perfect union with God, the latter as the absence of God. Whatever the concept of eternity, it is based on the demonstrably false idea that the hope of heaven and the fear of hell will prevent people from doing evil to one another here on earth.

Purgatory is the only state inhabited by reasonable grownups, never quite living up to our own moral expectations but always hoping to do better.