The church has lost its way on the road to gay marriage

Ding-dong the bells are going to chime. Or perhaps more accurately, since gay marriage became legal in England and Wales, ding-ding. Or dong-dong.

Not that the bells in question are in churches. Both the Church of England and the Catholic Church are doctrinally opposed to the idea of same-sex unions, though at least seven clergy couples are preparing to marry in defiance of their bishops.

But the loudest clerical voices are opposed. The executive secretary of something which likes to call itself Anglican Mainstream was darkly blogging last week to the effect that recent floods and storms are God’s verdict on the Marriage (Same Sex Couples) Act 2013. If that’s the mainstream, it doesn’t bear thinking about what might be found on the C of E’s wilder shores.

It’s not just the church. The Ukip party leader Nigel Farage last week described gay marriage as “a very big can of worms”. And a poll by ComRes for BBC Radio 5 Live revealed that 22 per cent of British adults would refuse an invitation to a same-sex wedding ceremony. They can’t all be Ukip voters, Nick Clegg must hope.

Of course, you can view a statistic like that either way. It shows a sizeable rump of popular opinion remains ill at ease with homosexuality. But it also reveals how rapid social change can be. Such a poll would have produced a very different answer only two or three decades ago.

Until recently the attitude of most people to gay relationships was hardly different from the notion set out by Aristotle. He saw man as disposed to procreative pairing in a purpose-driven world. In the Middle Ages, the church’s greatest philosopher, St Thomas Aquinas, extrapolated from Aristotle that homosexuality was therefore a diseased or morbid state. That is still Rome’s official position.

Attitudes to marriage, by contrast, have been much more fluid and organic. St Paul thought it a barely permissible way of avoiding lust pending the end of the world, which he believed was imminent. But the early medieval societies which followed saw it as an institution for cementing tribal relationships – as well as a mechanism for controlling promiscuity and the social chaos which unregulated sex would bring.

For centuries, marriage was a strategic tool to reinforce trading and diplomatic relationships because it created bonds of mutual familial obligation. The marrying couple had much less choice in the matter than did their elders. Women were disposed of as their fathers saw greatest advantage. Indeed, it was only in 1140 with the celebrated canon law textbook of the Benedictine monk Gratian that the bride and groom had even to give their verbal consent. Before that all they had to do was be present at the ceremony.

The nuptial norms of “for better, for worse; for richer, for poorer” date from Cranmer and the Reformation. The state got involved in weddings only with the Clandestine Marriage Act of 1753. And non-religious civil marriages had to wait for another century. Even then, nonconformists and Catholics were allowed to marry in their own churches only if a civil official was present to regularise their marriages. That practice survives to this day.

Despite the chivalric ballads of the medieval troubadours and the potent love verse of bards such as Shakespeare, it was only in Victorian times that the idea became commonplace that people should marry for love. The growth of a new economic class, the explosion of new money and the increase of social mobility loosened the old rigid social barriers within which marriages had been arranged, as readers of Jane Austen will know only too well.

Once love became the basis for marriage, it seemed inevitable, philosophically as well as socially, that the institution should be extended to any couple who love each other, whatever their gender. That is how the church, which had been ahead of the state in the promotion of marriage, found itself overtaken.

Today, the church has wedded itself to a particular form of communal organisation – the nuclear family – as not merely socially useful but “to the exclusion of all others”. And it has allowed itself to be enslaved to a list of practices outlawed at the time humankind was transitioning from the Bronze Age to the Iron Age; the biblical Book of Leviticus forbids, in addition to homosexuality, selling land, trimming your beard, eating rabbit pie and wearing clothes made from mixed fabrics – which is bad news for evangelicals with cotton and polyester shirts.

This is how it came to pass that, on the eve of the legalisation of gay marriage, a spokesman for the Catholic Church went on the radio outlining a powerful, densely textured, legalistic philosophical justification for its opposition to gay marriage which completely omitted all reference to love. This is a deeply unattractive paradox of which both the Archbishop of Canterbury and the current Pope seem keenly aware. Poor Justin Welby has two irreconcilable constituencies to keep happy; he cannot say what most people in the UK want to hear from the church for fear of breaking with those in the Anglican Communion, like the church in South Sudan, which vitally needs his support on life-and-death issues of peace and poverty.

Pope Francis – who turned the papal worldview upside down by saying of gays “who am I to judge?” – constantly insists that mercy must be elevated over moralising. But he has pharisaical backwoodsmen to deal with such as the Bishop of Portsmouth who has pronounced that the city’s gay, Catholic MP should not be taking Communion at Mass. That hardly sits well from a cleric who claims to be preaching a gospel which has “God is love” at its core.

The Prime Minister, David Cameron, greeted the historic decision to extend marriage to gay women and men by saying: “When people’s love is divided by law, it is the law that needs to change.” Amen, or ding-dong, to that.

Paul Vallely is visiting professor of public ethics at University of Chester