Recent months have brought fearsome reminders of the destructive force of corrupted religion. In the Swat region of Pakistan, a 17-year-old woman was publicly flogged, apparently for leaving her home without a male escort. A video of the beating, which shows the teenager writhing in pain and pleading for relief, has set off a national debate about the influence of radical Islam in the country. In Afghanistan, a group of 300 women defied an angry mob as they marched in the nation's capital to protest a law allowing marital rape. "Death to the enemies of Islam!" chanted their opponents. "We want Islamic law!" In Sudan, the Islamist government expelled humanitarian relief organizations after an international tribunal accused its leader of war crimes and issued a warrant for his arrest. "Here in Sudan, we are a liberation movement against this new colonization," proclaimed Omar al-Bashir, "and we are ready for any battle." The ejection of relief agencies has put the lives of at least a million internal refugees at risk.

Perhaps not since Europe's wars of religion has the public face of piety been so disfigured. These and similar stories feed the liberal view of faith as pathology. We are told that religious beliefs, if allowed to intrude into politics, become the mortal enemy of freedom. This slick narrative suffers, in fact, from its detachment from European history: It was the Christian culture of Europe, during a season of spiritual fervor, which produced an intellectual alliance of religion and human rights. What emerged, and ultimately prevailed, was an unashamedly biblical defense of freedom of thought that shook the political and clerical establishments of its day.

The Supreme Court of Reason

Three hundred years ago, in 1708, the first English translation of Pierre Bayle's A Philosophical Commentary appeared in London. This theological manifesto offered an erudite vindication of reason in the cause of religious toleration. Bayle was a French philosopher adored by later Enlightenment figures, yet he argued as a Protestant thinker whose high view of the Bible would send contemporary liberals into apoplexy. His work enlisted "natural reason" to defend the integrity of Scripture against Christian clergy whom he accused of abusing the Bible to justify persecution. "Whatever Doctrine is not vouch'd, as I may say, confirm'd and register'd in the supreme Court of Reason and natural Light," he declared, "stands on a very tottering and crazy Foundation."

The doctrine that Bayle set his sights on had been used to construct a theology of coercion for centuries. It was based on Jesus' parable of a banquet in Luke 14:23: "Compel them to come in, that my house may be filled." Citing the authority of Augustine, the Catholic Church endorsed a literal interpretation of the parable to authorize the use of lethal force against heretics. Many Protestants had done likewise, yet complained bitterly when Catholic France, under Louis XIV, revoked the Edict of Nantes in 1685 and launched a campaign of brutal persecution against its Protestant population. Thousands were imprisoned or sent to convents. Children were taken from their parents, baptized, and shipped off for adoption. At least 200,000 Protestants fled the country and became exiles throughout Europe.

This latest outburst of violence caused Bayle, himself a religious refugee in Holland, to defend toleration on explicitly Christian grounds. His lengthy work is a careful refutation of the church's rationale for coercion—using relentless logic to awaken conscience, interpret Scripture, and uphold the example of Jesus. The threat of force, Bayle argued, could never inspire genuine faith; instead, it corrupted the conscience and produced "acts of Hypocrisy and High Treason against the Divine Majesty." The use of Scripture to authorize violence was repugnant not only to reason, but also to the plain dictates of revelation. "One must transcribe almost the whole New Testament," he wrote, "to collect all the Proofs it affords us of that Gentleness and Long-suffering, which constitute the distinguishing and essential Character of the Gospel."

Bayle's interpretive style incensed Christian authorities, who often disregarded the grammatical and historical context of the Bible for the sake of dogma. At the same time, he rejected the Enlightenment philosophers who despised Christianity as irrational and inherently divisive. Bayle's goal was a society that protected each religious sect with equal vigor, as well as churches that granted one another mutual toleration. "If the Multiplicity of Religions prejudices the State, it proceeds from their not bearing with one another but on the contrary endeavoring each to crush and destroy the other by methods of Persecution," he reasoned. "In a word, all the Mischief arises not from Toleration, but from the want of it."

It was a revolutionary appeal. The assumption, shared by Catholics and Protestants, was that "Kings and Princes cou'd never be safe when their Subjects were of a different Persuasion." Claims for freedom of conscience were considered a pretext for sedition. Bayle turned the conventional wisdom on its head: religious pluralism, he argued, was the surest path to social and political stability.

No Gospel of Coercion

There were, to be sure, limits to Bayle's toleration. He remained deeply suspicious of Catholicism, for example, no doubt because his brother died in a French prison at the hands of Catholic magistrates. Nevertheless, Bayle criticized Protestant supporters of coercion for their betrayal of Christian ideals. He lamented the "havock which Religion has made in the World" because of the clerical lust for power. He defended unpopular religious groups and even suggested that atheists could be good citizens—a view considered scandalous by his contemporaries.

Like his friend and fellow advocate for religious freedom, English philosopher John Locke, Bayle's writings were hotly debated in Europe. Modern scholars disagree over Bayle's ultimate religious beliefs; he has been called a deist, rationalist, Unitarian, and atheist. We can't be certain about his personal commitment to Christian orthodoxy. What seems clear, however, is that Bayle's public defense of religious liberty drew its strength from biblical doctrines. His arguments pushed Protestant principles, such as the sanctity of conscience and the intelligibility of Scripture, toward their logical conclusion. His theory of toleration later earned the esteem of the American Founders: Franklin praised his defense of atheists and Jefferson recommended that his work be included in the original Library of Congress.

Modern thinkers often associate toleration with the decline of religion. For many skeptics and cultural elites, the secular Enlightenment provided the remedy to the religious disease by subjugating Christian teachings to democratic values. In Divided by Faith: Religious Conflict and the Practice of Toleration in Early Modern Europe, Benjamin Kaplan notes the persistence of the secularization theory among historians and other scholars. He describes a consensus that "rationalism and secularization, not Protestantism, had brought about a long-term rise of toleration in the West."

Bayle's Philosophical Commentary suggests just the opposite. "Since therefore it's certain that no one wou'd have his Conscience forc'd," he wrote, "let's firmly believe that Jesus Christ never design'd that his Followers shou'd compel." Call it the golden rule of toleration. If this was the gospel preached by the advance guard of the Enlightenment, it is welcome news in any season.

Joseph Loconte is a senior research fellow at The King's College in New York City. He is working on a book about the history of religious freedom in the West.