E Jane Dickson: If I were the Pope, I wouldn't quote Aristotle

Clearly St Thomas Aquinas doesn’t leave a lot of wriggle room for gay sex

This week's conundrum from the Ministry of Good Intentions: some equality laws are more equal than others.

It doesn't begin to make sense, but this is the Orwellian realpolitik we're faced with in view of the Government's decision to back down over the proposed amendment to its Equality Bill. On Wednesday, following a trouncing in the Lords and a broadside from the Pope, Equality Minister Harriet Harman confirmed she is no longer seeking "clarification" on the exemption of religious organisations from standard employment law.

It was never that big an amendment. UK law already exempts churches from anti-discrimination legislation concerning the appointment of, say, women or homosexuals, to the priesthood or other "religious posts". Since the law was introduced in 2003, however, religious bodies have unofficially stretched exemption to cover non-religious posts within their organisations. The clarification, pursued, until Wednesday, with some vigour by Ms Harman, would only have closed this loophole.

One man's loophole, another's slippery slope. Certainly it was all too much for Pope Benedict XVI, who, on Monday, took the opportunity of his meeting with Catholic bishops from England and Wales to launch a direct attack on the Equality Bill. "In some respects," he pronounced, "it actually violates the natural law upon which the equality of all human beings is granted and by which it is guaranteed."

The pontiff did not make explicit his egalitarian concerns, but the invoking of "natural law" in connection to legislation which, unamended, could effectively bar gay men and women from senior positions within Catholic organisations, sends a clear enough signal.

Based on the teaching of St Thomas Aquinas, "natural law" is the concept which has underpinned Catholic attitudes to sex and sexuality since the 13th century. Building on the Aristotelian notion that "in all things of nature, there is something of the marvellous" , Aquinas held that the natural instinct of man to procreate was evidence of his essential goodness. The flip side to Aquinas' theory (which might have surprised old Aristotle) was that sex for any purpose other than procreation was sinful.

He was something of a hardliner on this, to the point of insisting that rape and incest, since they might result in conception, were less reprehensible than coitus interruptus. You could pursue this theory down several interesting avenues (what would Aquinas make of the rhythm method, the only birth control approved by the Catholic Church?), but clearly it doesn't leave a lot of wriggle room for gay sex and accordingly homosexuality remains a focus of acute anxiety for the Catholic Church.

Setting aside the relevance of a 13th-century mystic's wacko interpretation of Greek philosophy to the British legislative system, there is some irony in the Pope's attempted intervention to our employment laws; if all the homosexuals in the employ of the Catholic Church were to walk out in protest tomorrow, it is a statistical probability that the clergy, let alone the "lay officials", would be significantly depleted. And the church would be the poorer for it.

Rather than obsessing on the sexuality of the "hordes without", Benedict might more profitably reappraise urgent sexual issues within the church community. And it seems to me he could start by taking a long Aristotelian look at the concept and consequences of clerical celibacy.

Benedict XVI has done more than previous popes to address the issue of the sexual abuse of children within the Catholic Church. Many within and without the church are all too eager to align this horrific, historically institutionalised crime with the perceived "homosexual threat", piling insult and injury in an unstable heap. It is pernicious and wholly inaccurate to confuse homosexuality with paedophilia.

At this stage – and who can bear to guess the final reckoning? – more boys appear to have been abused by priests than girls and I suspect the reasons for this are brutally circumstantial; altar boys are close to hand and they can't get pregnant. Evidence of a link between child abuse and the church's ruling on clerical celibacy may be equally circumstantial, but I'd say it bears earnest scrutiny.

The Pope, of course, is not alone in denouncing the Equality Bill. Hard on the papal heels, Archbishop John Sentamu, the second most senior cleric in the Church of England, applauded the Lords for rejecting an amendment he denounced as an " unjust" restriction on religious freedom and an attempt to distance religion from public life. Which raises a pressing question. Why are 26 seats in the House of Lords reserved for Anglican bishops? (That's a whole section of Parliament, by the way, where women, by virtue of the church's ruling on the episcopy, are barred.)

The Pope and the Archbishop have every right to voice their political views. You might say it's part of their contract. On the other hand, politics has no obligation to regard them. Aristotle, on the other hand, always come in handy. Ms Harman might usefully have mugged up on his maxim: "Even when laws have been written down, they ought not always to remain unaltered."