Editor's Note: The controversy over a proposed mosque in lower Manhattan has spurred a wider debate about the nature of Islam. We asked six leading thinkers to answer the question: What is moderate Islam?  •Anwar Ibrahim: The Ball Is in Our Court  •Bernard Lewis: A History of Tolerance  •Ed Husain: Don't Call Me Moderate, Call Me Normal  •Reuel Marc Gerecht: Putting Up With Infidels Like Me  •Tawfik Hamid: Don't Gloss Over The Violent Texts  •Akbar Ahmed: Mystics, Modernists and Literalists  Skeptics and cynics alike have said that the quest for the moderate Muslim in the 21st century is akin to the search for the Holy Grail. It's not hard to understand why. Terrorist attacks, suicide bombings and the jihadist call for Muslims "to rise up against the oppression of the West" are widespread.  The radical fringe carrying out such actions has sought to dominate the discourse between Islam and the West. In order to do so, they've set out to foment anti-Americanism and anti-Semitism. They've also advocated indiscriminate violence as a political strategy. To cap their victory, this abysmal lot uses the cataclysm of 9/11 as a lesson for the so-called enemies of Islam.  These dastardly acts have not only been tragedies of untold proportions for those who have suffered or perished. They have also delivered a calamitous blow to followers of the Muslim faith.  These are the Muslims who go about their lives like ordinary people—earning their livings, raising their families, celebrating reunions and praying for security and peace. These are the Muslims who have never carried a pocketknife, let alone explosives intended to destroy buildings. These Muslims are there for us to see, if only we can lift the veil cast on them by the shadowy figures in bomb-laden jackets hell-bent on destruction.  These are mainstream Muslims—no different from the moderate Christians, Jews and those of other faiths—whose identities have been drowned by events beyond their control. The upshot is a composite picture of Muslims as inherently intolerant, antidemocratic, inward-looking and simply unable to coexist with other communities in the modern world. Some say there is only one solution: Discard your beliefs and your tradition, and embrace pluralism and modernity.  The Ottoman-era Sultan Ahmed or Blue Mosque in Istanbul.  This prescription is deeply flawed. The vast majority of Muslims already see themselves as part of a civilization that is heir to a noble tradition of science, philosophy and spirituality that places paramount importance on the sanctity of human life. Holding fast to the principles of democracy, freedom and human rights, these hundreds of millions of Muslims fervently reject fanaticism in all its varied guises.  Yet Muslims must do more than just talk about their great intellectual and cultural heritage. We must be at the forefront of those who reject violence and terrorism. And our activism must not end there. The tyrants and oppressive regimes that have been the real impediment to peace and progress in the Muslim world must hear our unanimous condemnation. The ball is in our court.  Mr. Ibrahim is Malaysia's opposition leader.  A form of moderation has been a central part of Islam from the very beginning. True, Muslims are nowhere commanded to love their neighbors, as in the Old Testament, still less their enemies, as in the New Testament. But they are commanded to accept diversity, and this commandment was usually obeyed. The Prophet Muhammad's statement that "difference within my community is part of God's mercy" expressed one of Islam's central ideas, and it is enshrined both in law and usage from the earliest times.  This principle created a level of tolerance among Muslims and coexistence between Muslims and others that was unknown in Christendom until after the triumph of secularism. Diversity was legitimate and accepted. Different juristic schools coexisted, often with significant divergences.  Sectarian differences arose, and sometimes led to conflicts, but these were minor compared with the ferocious wars and persecutions of Christendom. Some events that were commonplace in medieval Europe— like the massacre and expulsion of Jews—were almost unknown in the Muslim world. That is, until modern times.  Occasionally more radical, more violent versions of Islam arose, but their impact was mostly limited. They did not become really important until the modern period when, thanks to a combination of circumstances, such versions of Islamic teachings obtained a massive following among both governments and peoples.  From the start, Muslims have always had a strong sense of their identity and history. Thanks to modern communication, they have become painfully aware of their present state. Some speak of defeat, some of failure. It is the latter who offer the best hope for change.  For the moment, there does not seem to be much prospect of a moderate Islam in the Muslim world. This is partly because in the prevailing atmosphere the expression of moderate ideas can be dangerous—even life-threatening. Radical groups like al Qaeda and the Taliban, the likes of which in earlier times were at most minor and marginal, have acquired a powerful and even a dominant position.  But for Muslims who seek it, the roots are there, both in the theory and practice of their faith and in their early sacred history.  Mr. Lewis, professor emeritus at Princeton, is the author of "From Babel to Dragomans: Interpreting the Middle East" (Oxford University Press, 2004).  I am a moderate Muslim, yet I don't like being termed a "moderate"—it somehow implies that I am less of a Muslim.  We use the designation "moderate Islam" to differentiate it from "radical Islam." But in so doing, we insinuate that while Islam in moderation is tolerable, real Islam—often perceived as radical Islam—is intolerable. This simplistic, flawed thinking hands our extremist enemies a propaganda victory: They are genuine Muslims. In this rubric, the majority, non-radical Muslim populace has somehow compromised Islam to become moderate.  What is moderate Christianity? Or moderate Judaism? Is Pastor Terry Jones's commitment to burning the Quran authentic Christianity, by virtue of the fanaticism of his action? Or, is Rabbi Ovadia Yosef, the spiritual head of the Shas Party in Israel, more Jewish because he calls on Jews to rain missiles on the Arabs and "annihilate them"?  The pastor and the rabbi can, no doubt, find abstruse scriptural justifications for their angry actions. And so it is with Islam's fringe: Our radicals find religious excuses for their political anger. But Muslim fanatics cannot be allowed to define Islam.  The Prophet Muhammad warned us against ghuluw, or extremism, in religion. The Quran reinforces the need for qist, or balance. For me, Islam at its essence is the middle way in all matters. This is normative Islam, adhered to by a billion normal Muslims across the globe.  Normative Islam is inherently pluralist. It is supported by 1,000 years of Muslim history in which religious freedom was cherished. The claim, made today by the governments of Iran and Saudi Arabia, that they represent God's will expressed through their version of oppressive Shariah law is a modern innovation.  The classical thinking within Islam was to let a thousand flowers bloom. Ours is not a centralized tradition, and Islam's rich diversity is a legacy of our pluralist past.  Normative Islam, from its early history to the present, is defined by its commitment to protecting religion, life, progeny, wealth and the human mind. In the religious language of Muslim scholars, this is known as maqasid, or aims. This is the heart of Islam.  I am fully Muslim and fully Western. Don't call me moderate—call me a normal Muslim.  Mr. Husain is author of "The Islamist" (Penguin, 2007) and co-founder of the Quilliam Foundation, a counterextremist think tank.  Moderate Islam is the faith practiced by the parents of my Pakistani British roommate at the University of Edinburgh—and, no doubt, by the great majority of Muslim immigrants to Europe and the United States.  Khalid's mother and father were devout Muslims. His dad prayed five times a day and his mom, who hadn't yet learned decent English after almost 20 years in the industrial towns of West Yorkshire, gladly gave me the impression that the only book she'd ever read was the Quran.  I was always welcome in their home. Khalid's mother regularly stuffed me with curry, peppering me with questions about how a non-Muslim who'd crossed the Atlantic to study Islam could resist the pull of the one true faith.  Determined to keep their children Muslim in a sea of aggressive, alcohol-laden, sex-soaked disbelief, they happily practiced and preached peaceful coexistence—even with an infidel who was obviously leading their son down an unrighteous path.  That is the essence of moderation in any faith: the willingness to exist peacefully, if not exuberantly, alongside nonbelievers who hold repellant views on many sacred subjects.  It is a dispensation that comes fairly easily to ordinary Muslims who have left their homelands to live among nonbelievers in Western democracies. It is harder for Muslims surrounded by their own kind, unaccustomed by politics and culture to giving up too much ground.  Tolerance among traditional Muslims is defined as Christian Europe first defined the idea: A superior creed agrees not to harass an inferior creed, so long as the practitioners of the latter don't become too uppity. Tolerance emphatically does not mean equality of belief, as it now does in the West.  Even in Turkey, where authoritarian secularism has changed the Muslim identity more profoundly than anywhere else in the Old World, a totally secularized Muslim would never call a non-Muslim citizen of the state a Turk. There is a certain pride of place that cannot be shared with a nonbeliever. Wounded pride also does the Devil's work on ecumenicalism. Adjusting to modernity, with its intellectually open borders and inevitable moral chaos, is brutally hard for monotheisms, especially for those accustomed to rule. But it happens.  When I told Khalid's father that his children—especially his daughters—would not worship the faith as he and his wife had done, he told me: "They are living a better life than we have lived. That is enough."  Mr. Gerecht, a former CIA operative, is a senior fellow at the Foundation for Defense of Democracies.  In regards to Islam, the words "moderate'" and "radical" are relative terms. Without defining them it is virtually impossible to defeat the latter or support the former.  Radical Islam is not limited to the act of terrorism; it also includes the embrace of teachings within the religion that promote hatred and ultimately breed terrorism. Those who limit the definition of radical Islam to terrorism are ignoring—and indirectly approving of—the Shariah teachings that permit killing apostates, violence against women and gays, and anti-Semitism.  Moderate Islam should be defined as a form of Islam that rejects these violent and discriminatory edicts. Furthermore, it must provide a strong theological refutation for the mainstream Islamic teaching that the Muslim umma (nation) must declare wars against non-Muslim nations, spreading the religion and giving non-Muslims the following options: convert, pay a humiliating tax, or be killed. This violent concept fuels jihadists, who take the teaching literally and accept responsibility for applying it to the modern world.  Moderate Islam must not be passive. It needs to actively reinterpret the violent parts of the religious text rather than simply cherry-picking the peaceful ones. Ignoring, rather than confronting or contextualizing, the violent texts leaves young Muslims vulnerable to such teachings at a later stage in their lives.  Finally, moderate Islam must powerfully reject the barbaric practices of jihadists. Ideally, this would mean Muslims demonstrating en masse all over the world against the violence carried out in the name of their religion.  Moderate Islam must be honest enough to admit that Islam has been used in a violent manner at several stages in history to seek domination over others. Insisting that all acts in Islamic history and all current Shariah teachings are peaceful is a form of deception that makes things worse by failing to acknowledge the existence of the problem.  Mr. Hamid, a former member of the Islamic radical group Jamma Islamiya, is an Islamic reformer and a senior fellow at the Potomac Institute for Policy Studies.  In the intense discussion about Muslims today, non-Muslims often say to me: "You are a moderate, but are there others like you?"  Clearly, the use of the term moderate here is meant as a compliment. But the application of the term creates more problems than it solves. The term is heavy with value judgment, smacking of "good guy" versus "bad guy" categories. And it implies that while a minority of Muslims are moderate, the rest are not.  Having studied the practices of Muslims around the world today, I've come up with three broad categories: mystic, modernist and literalist. Of course, I must add the caveat that these are analytic models and aren't watertight.  Muslims in the mystic category reflect universal humanism, believing in "peace with all." The 13th-century Sufi poet Rumi exemplifies this category. In his verses, he glorifies worshipping the same God in the synagogue, the church and the mosque.  The second category is the modernist Muslim who believes in trying to balance tradition and modernity. The modernist is proud of Islam and yet able to live comfortably in, and contribute to, Western society.  Most Muslim leaders who led nationalist movements in the first half of the 20th century were modernists—from Sultan Mohammed V, the first king of independent Morocco, to M.A. Jinnah, who founded Pakistan in 1947. But as modernists failed over time, becoming increasingly incompetent and corrupt, the literalists stepped into the breach.  The literalists believe that Muslim behavior must approximate that of the Prophet in seventh-century Arabia. Their belief that Islam is under attack forces many of them to adopt a defensive posture. And while not all literalists advocate violence, many do. Movements like the Muslim Brotherhood, Hamas, and the Taliban belong to this category.  In the Muslim world the divisions between the three categories I have delineated are real. The outcome of their struggle will define Islam's fate.  The West can help by understanding Muslim society in a more nuanced and sophisticated way in order to interact with it wisely and for mutual benefit. The first step is to categorize Muslims accurately.  Mr. Ahmed, the former Pakistani ambassador to Britain, is the chair of Islamic studies at American University and author of "Journey into America: The Challenge of Islam" (Brookings, 2010).
In the Wall Street Journal six leading thinkers—Anwar Ibrahim, Bernard Lewis, Ed Husain, Reuel Marc Gerecht, Tawfik Hamid and Akbar Ahmed—weigh in on this pressing question.