WHEN Desiderius Erasmus was born around 1466, the Christian West was on the brink of a dreadful era of religious conflict, pitting Catholics against various shades of Protestant Reformers. Theological differences that appear arcane or even meaningless to many people today triggered a seemingly interminable round of local and international wars. By the standards of that terrible age, Erasmus stood for moderation, reason and the pursuit of truth through diligent investigation. He believed that truth was more likely to emerge from a calm exchange of views than from insults or name-calling.

Erasmus sympathised with the Protestants’ complaints about abuses and corruption in the Church, but thought the Reformers were wrong to reject the idea of free will. Whenever hard questions arose about how to interpret the Judeo-Christian tradition, he believed in studying all the relevant material in the original languages. As one of the fathers of European humanism, he gave his name to a university in his native Rotterdam, to a programme that helps young Europeans study abroad and to a controversial way of pronouncing Greek.

All this makes Erasmus a fitting name for this new blog, on religion and public policy. I will do my best to emulate some of his virtues as I delve into the religious differences of today, whether they are fought out on an intellectual plane in classrooms, legislatures and courtrooms, or in a more physical sense with bombs and bullets, as can still tragically happen in places ranging from the Balkans to Baghdad. Again and again I expect to find myself asking that Erasmian question: how is freedom best served?

In democratic countries, almost everybody agrees that religious freedom is a supremely important ideal. That has been especially true in the United States, ever since Thomas Jefferson stood up for freedom of conscience in his home state of Virgina, declaring that

Whereas Almighty God hath created the mind free; that all attempts to influence it by temporal punishment or burthens, or by civil incapacitations, tend only to beget habits of hypocrisy and meanness, and are a departure from the plan of the Holy author of our religion…

As with all sacred writ, however, the interpretation of Jefferson’s ideal has remained intensely controversial. For American conservatives, the hottest “religious freedom” issue today is posed by Liberty University’s challenge to the “Obamacare” health policy which requires employers to provide contraceptive services to their employees. To blase European liberals, that might sound like an eccentric obsession among American “theocons”. But in Europe, too, the meaning of liberty is controversial. Last year the European Court of Human Rights upheld the right of Spain’s Catholic bishops to fire a religion teacher who campaigns for the right of priests to marry. A conservative lobby group hailed that decision as a victory for religious freedom; to secularists, it seemed the opposite.

This blog is launched just as the world’s 1.2 billion Catholics await a successor to Benedict XVI, a pope who thought Christianity, with its Greek and Hebrew roots, offered a unique synthesis between faith and reason. That is a belief that Muslims and atheists alike would contest, but Benedict used his well-honed Germanic intellect to argue it with vigour. Will his successor be another cerebral type, emphasising reason, or somebody who fosters the passionate, ecstatic kinds of worship that seem to be Christianity's main growth area? Or a bit of both? Almost equally difficult balancing acts will be attempted by Justin Welby, the new leader of the world’s 80m Anglicans, as he struggles to keep North American liberals and African traditionalists in the same Communion.

In the realm of Islam, theological disputes still have a violent edge. Whatever its causes, conflict in Syria is sharpening differences between the Muslim world’s Sunni majority and the non-Sunni strains of Islam which hold sway in Damascus, Baghdad and Teheran. In Erasmus's native Europe, meanwhile, assertive Muslim minorities are straining, though not so far exhausting, the capacity of democracy to deal with new social realities. Erasmus’s home city of Rotterdam is the first major European city to have a Muslim mayor; it is one of several European cities where inter-faith tensions have flared and somehow been managed.

Across the world, the number of people living under some degree of religious repression has been increasing; only a quarter of the world's people now enjoy religious freedom according to one recent study. That partly reflects the fact that countries which restrict freedom are extremely populous. The Chinese authorities are making life harder for a burgeoning movement of Christian house churches, and blaming the eirenic Dalai Lama for the actions of Tibetan Buddhists who burn themselves to death. The old Erasmus would be troubled by all these developments, but he would neither despair nor be distracted from his belief in sifting the evidence and patiently searching for the truth. I hope I can do likewise.