Giacomo Leopardi CAN theists and atheists live together in any sort of mutual respect? That is far more than an academic debating point. Throughout history, theocrats have punished dissidents who rejected the state religion. In the 20th century, atheist regimes subjected religion to bloody repression, and a few, like North Korea, still do. And in recent years, especially in the Islamic world, there has been a resurgence in the persecution of those who reject the prevailing form of religion, or all religion. The rise in religious repression is one of the factors that galvanised "new atheists" like the late Christopher Hitchens, who thought "religion poisons everything" and Richard Dawkins, the biologist who has argued that religion has a unique capacity to make good people do bad things. But there is another sort of cerebral atheism. John Gray, one of Britain's top public intellectuals, is a strong advocate of the view that theism and atheism can coexist in freedom and a sort of amity. (Yes, Britain does have intellectuals, even though it would be a kiss of death if, as happens in France, "100 intellectuals" were to declare their support for a particular party or candidate for British office.)

In his latest trope on that theme, an essay for the BBC website, Mr Gray cited the examples of two non-believers who were, for different reasons, respectful of religion. One was the Italian thinker and poet Giacomo Leopardi (1798-1837, pictured), who rejected the conservative Catholicism in which he grew up. Leopardi intuited, correctly as it turned out, that militant secularism would take forms that were even bloodier than the French Revolution whose aftermath he saw. In Leopardi's view, religion as he knew it was preferable to the sort of armed atheism that would one day take shape. Mr Gray's other example is Llewellyn Powys (1884-1938), one of several members of a clerical family from England's West country who became lightish popular writers. Dogged by poor health, Powys was a hedonist who believed in seizing the moment and enjoying the pleasures of nature and love; but he still acknowledged religion as "a kind of poetry which fortified the human spirit in the face of death."

Mr Gray could have chosen more contemporary eggheads. Giuliano Ferrara, an Italian newspaper editor and friendly interlocutor with the Vatican, is an atheist and erstwhile communist who admires the Catholic church for defending Christian culture. Terry Eagleton, a British-born literary theorist influenced both by Marxism and by the Catholicism in which he was raised, is not formally religious, but is sharply critical of the new atheists for misunderstanding religion. A similar line is taken by Karen Armstrong, a former nun and best-selling writer, who became badly disillusioned with Catholicism. She insists that the word God refers not to a true-or-false proposition but to a human quest for meaning and transcendence. Like Leopardi, she seems more preoccupied by secularist brutality than the religious sort.

What about the theist side of the discussion? Can people who believe in God live amicably with those who don't? Perhaps that raises a harder question. For those who see the existence of God as not merely true but, in a sense, truer than anything else, how is it possible to respect people who disagree? In a western world that no longer burns heretics, most religious people would probably say something like this: faith in God is an existential choice which only has value if it is made in absolute freedom, and that freedom must also imply the right of people to say no. From this viewpoint, the right to atheism underpins faith. In liberal readings of Islam, meanwhile, the Koranic statement that "there is no compulsion in religion" is taken as a statement of value more than mere fact; religion has no merit if it is embraced under duress.

David Jenkins is a maverick Anglican cleric who was accused of atheist tendencies when he was bishop of Durham. He denied the charge, but he did once argue that theism and atheism were, in some paradoxical way, two sides of the same coin. In a 1966 book entitled "Guide to the Debate about God", he minutely explained the theological ideas of brainy Teutons like Friedrich Schleiermacher, Rudolf Bultmann and Karl Barth, and then concluded, enigmatically: "In the end there are no adequate reasons for God's existence. He is. The atheist also understands this. He does not believe."

If the clash between theism and atheism were merely about metaphysical ideas, personal choices, or even quests made by consenting adults, then it should indeed be a negotiable difference in societies which allow for many other kinds of diversity. Thinkers like Mr Gray or even Bishop Jenkins may help us negotiate. But they do not entirely solve the problem. It is striking that the most intractable disputes between believers and non-believers concern the treatment of children: how and by whom they should be raised; what they should be taught about the origin of the world; whether, in the name of religious custom, their bodies should be mutilated; whether the education of boys and girls should be separate and in some way differentiated, as conservative Islam mandates; and at what point in their biological development one can speak of a life which cannot morally be terminated. With or without the guidance of brainy public intellectuals, these are hard arguments which lead to hard choices.