Damon Linker asks whether gay marriage isn’t the next logical step in a cultural progression that begins with Christianity’s radical egalitarianism:

For Tocqueville, the march of equality was upending age-old institutions and moral habits “in all the Christian world.” It was a “providential fact,” by which he meant that there was nothing anybody could do to stop it.

The ultimate source of the democratic revolution — the motor behind its inexorable unfolding — is the figure of Jesus Christ, who taught the equal dignity of all persons, and declared in the Sermon on the Mount that the last shall be first and the first shall be last, and that the meek shall inherit the earth.

These are among the most subversive teachings ever uttered — and according to Tocqueville, Western civilization has been working out their logic for the better part of two millennia, as political communities have applied Christ’s egalitarian teachings in stricter and stricter terms.

An interesting argument. But what about the other radically egalitarian monotheist religion: Islam?

Islam is supposed to be a brotherhood of believers in which all are regarded equally by the divine. Pharaoh is the Quranic representation of outrageous arrogance, the man who would make a god of himself rather than submit to the only true divinity. Just as Christianity was an appealing religion to the slaves of the Roman Empire, when Islam reached India, it became a primary mode of escape from the caste system for many low-caste Hindus.

There is no hereditary priesthood in Islam (unlike in, say, ancient Israelite religion). The hierarchy of Islamic jurisprudence, at least in its dominant Sunni variety, is in theory both meritocratic and libertarian; you gain authority as an interpreter of Islamic law by convincing other interpreters to follow your interpretations. (This is the way rabbinic authority historically worked as well.) De Tocqueville’s argument that the openness of the priesthood to different classes paved the way for modern democracy should be even more true of Islam.

While most Islamic societies have been monarchies for most of their history, the same is true of most Christian societies; Islam, however, does not have a doctrine comparable to the “divine right of kings.” Indeed, for most of the history of Christianity, the Catholic Church proclaimed that monarchy was the only political system in harmony with Christian principles, reversing course on this point only very recently. Similarly, yes, most Islamic societies were slave societies for most of their histories – but most Christian societies embraced slavery and/or its close cousin, serfdom. Meanwhile, Islam has been far more consistent historically in rejecting religious sanction for race-based slavery or a natural hierarchy among humanity. The same cannot be said of Christian societies.

Finally, Islam emphatically believes in bringing the actual social world into line with its ideal conception thereof, while Christianity frequently gestures in the opposite direction, declaring its kingdom to be “not of this world” and talking about rendering unto Caesar what is Caesar’s. If gay marriage is the “logical” result of a leveling egalitarianism, then surely the Islamic religious matrix is where it would emerge.

Or, you know – not.

When I first read the title of Linker’s piece, I thought he was going to make a different argument for Christianity’s implication in the movement for gay marriage by pointing to Christianity’s rejection of the cycle of procreation and death, its valorization of celibacy and friendship over the value of marriage and clan continuity, and showing how these ideas make it hard to argue against gay relationships as somehow against the proper order of things as ordained by God. The Cathars were a Christian heresy – and a very popular one – that embraced non-procreative sexual activity; the association was strong enough that the coarse term, “bugger,” originates as an epithet for the Cathars. Maybe this is the true intellectual genealogy of marriage: not in Christianity’s radical egalitarianism, but in its rejection of procreation? I certainly think you could write a persuasive column based on that argument.

Except . . . what about the Buddhists? Who also have a celibate priestly class. Who also focus on an escape from the cycle of procreation and death. If this is the intellectual genealogy, why should gay marriage have originated in the secularizing Christian West rather than in, say, Thailand?

Maybe the problem with all these kinds of arguments is that ideas don’t have consequences – at least, not in the way that Linker wants them to. The older I get, the less Hegelian and the more Darwinian I get about the way that culture changes over time. That is to say: I am less and less convinced that a conversation about ideas is the motor of history, and more and more convinced that cultures prove themselves more or less adapted to challenges – material or ideational – that their cultures could not possibly have foreseen.

The political democracy that de Tocqueville studied emerged in the Christian west after the discovery and settlement of the New World; the ructions of the Protestant Reformation and the Catholic Counter-Reformation (was the former the “true” Christian development, and the latter somehow “false”?); the transformation of both the British and French monarchies into more autocratic, less-feudal systems; the emergence of capitalism as an economic system; the rise of the trans-Atlantic slave trade; and a world war between Britain and France. Which of these momentous developments do we fully understand? Which is the inevitable outgrowth of the Christian idea, as opposed to a contingent historical development?

Christianity was around for two millennia before the idea of gay marriage reared its head. Moreover, Christianity arose in a Roman world that was not exactly reticent about sexuality or about the existence of same-sex attraction. Heck, the Emperor Nero married a man! And yet, we are having this argument now, not in Nero’s time. Why, then, should we think that Christianity has anything to do with it?

When I read Augustine’s argument that marriage is a sacrament, I see an argument equally applicable to gay couples as to straight. But that merely demonstrates that his ideas are – in my view, not the view of an orthodox Christian – more readily adaptable to the challenge posed by gay couples demanding recognition than, say, the views of comparable figures in my own religious tradition (Judaism). It doesn’t prove that those gay couples are making their demand because of the inevitable working out of Christian principles, because there is no such thing as the inevitable working out of principles, Christian or otherwise. History just doesn’t work like that.