At least since the first petals of the counterculture bloomed across Europe and the United States in the 1960s, it has been fashionable to affirm that all religions are beautiful and all are true.
This claim, which reaches back to "All Religions Are One" (1795) by the English poet, printmaker, and prophet William Blake, is as odd as it is intriguing.
The most popular metaphor for this view portrays the great religions as different paths up the same mountain. "It is possible to climb life's mountain from any side, but when the top is reached the trails converge," writes philosopher of religion Huston Smith.
This is a lovely sentiment but it is dangerous, disrespectful and untrue. For more than a generation we have followed scholars and sages down the rabbit hole into a fantasy world in which all gods are one.
This wishful thinking is motivated in part by an understandable rejection of the exclusivist, missionary view that only you and your kind will make it to heaven or paradise.
For most of world history, human beings have seen religious rivals as inferior to themselves – practitioners of empty rituals, perpetrators of bogus miracles, purveyors of fanciful myths. The Age of Enlightenment in the 18th Century popularized the ideal of religious tolerance, and we are doubtless better for it. But the idea of religious unity is wishful thinking nonetheless, and it has not made the world a safer place.
In fact, this naive theological groupthink has made the world more dangerous by blinding us to the clashes of religions that threaten us worldwide. It is time we climbed out of the rabbit hole and back to reality.
The world's religious rivals do converge when it comes to ethics, but they diverge sharply on doctrine, ritual, mythology, experience and law. These differences may not matter to mystics or philosophers of religion, but they matter to ordinary religious people.
Muslims do not think that the pilgrimage to Mecca they call the hajj is inessential. In fact, they include it among the Five Pillars of Islam. Roman Catholics do not think that baptism is inessential. In fact, they include it among their seven sacraments.
But religious differences do not just matter to religious practitioners. They have real effects in the real world. People refuse to marry this Muslim or that Hindu because of them. And in some cases, religious differences move adherents to fight and to kill.
One purpose of the "all religions are one" mantra is to stop this fighting and this killing. And it is comforting to pretend that the great religions make up one big, happy family. But this sentiment, however well intentioned, is neither accurate nor ethically responsible.
Faith in the unity of religions is just that – faith (perhaps even a kind of fundamentalism).
One reason we are willing to follow our fantasies down the rabbit hole of religious unity is that we have become uncomfortable with argument. Especially when it comes to religion, we desperately want everyone to get along.
In my Boston University courses, I work hard to foster respectful arguments. My students are good with "respectful," but they are allergic to "argument." They see arguing as ill-mannered, and even among friends they avoid it at almost any cost.
The ideal of religious tolerance has morphed into the straitjacket of religious agreement. Yet we know in our bones that the world's religions are different from one another. We pretend these differences are trivial because it makes us feel safer, or more moral. But pretending that the world's religions are the same does not make our world safer. Like all forms of ignorance, it makes our world more dangerous.
What we need on this furiously religious planet is a realistic view of where religious rivals clash and where they can cooperate.
Approaching this volatile topic from this new angle may be scary. But the world is what it is. And both tolerance and respect are empty virtues until we actually know something about whomever it is we are supposed to be tolerating or respecting.
Unfortunately, we live in a world where religion seems as likely to detonate a bomb as to defuse one. So while we need idealism, we need realism even more.
Whether the world's religions are more alike than different is one of the crucial questions of our time. In the 21st century alone, religion has toppled the Bamiyan statues of the Buddha in Afghanistan and the Twin Towers in New York City. It has stirred up civil war in Sri Lanka and Darfur. And it has resisted coalition troops in Iraq.
In many countries, religion has a powerful say in determining what people will eat and under what circumstances they can be married or divorced. Religious rivalries are either simmering or boiling over in Burma (Myanmar), Uganda, Sudan and Kurdistan. The contest over Jerusalem and the Middle East is at least as religious as it is economic or political. Hinduism and Buddhism were key motivators in the decades-long civil war that recently ravaged Sri Lanka.