You cannot point to the effect on the emotional development of children, of a culture in which homosexuality is treated as a legitimate way of life, nor can you allude to the correlation between male homosexuality and pedophilia. Some writers have gone public on these issues-Jeffrey Satinover, for example, in Homosexuality and the Politics of Truth (1996)-and paid a predictable price for it. Others have simply turned a blind eye and hoped that it will all go away or decided that in any case, in our promiscuous world, it hardly matters who does what with whom.

But it does matter, and it matters most of all not to you and me, who are grown up enough to deal with it, but to our children. This is where the real issue has been fudged in the European debates and is being increasingly fudged in America. Marriage is not about endorsing a sexual attachment between adults. It is about creating the conditions in which children can come into the world fully protected and with a fair chance of being loved. Marriage does not exist for the benefit of the present generation but for the benefit of the next. It is a rite of passage in which two people set out on a path whose meaning lies not in their present emotions but in their future family. As in all rites of passage, the meaning of marriage is not individual but social, and any attempt to rewrite marriage as a deal between the living is a negation of its real meaning, as a bond between the living and the unborn-a bond in which the dead too have an interest. If David Cameron really were as conservative as he claims, that would be the language he would use in giving voice to his views about marriage-the language of Edmund Burke.

As for the relations between the living, it is not as if these are in any way hampered by the existing legal order. In most European countries there are already ways in which homosexual men and women can ratify their relations in the form of "civil partnerships," which confer the legal benefits and burdens of marriage without implying the radical change of status that marriage has traditionally signified. The activists are not content with this arrangement, not because it does not provide the security that true love requires, but because it still implies that there is a difference between heterosexual and homosexual relations. So offended are they by this implication that they are prepared to level the charge of homophobia against anyone who gives voice to it. In the current climate of opinion in Europe, no politician, no journalist, and no churchman can risk inviting this charge.

Like other "thought crimes," homophobia lacks a definition and has no identity in law; you don't know how to avoid committing this crime, since all lines of inquiry might suddenly turn a corner and land you in the midst of it. The only safe option is to keep your mouth shut, or else to join the crowd and shout "homophobia" in your turn at whichever victim has been currently singled out for persecution. We are already seeing this among the Church of England bishops, many of whom seem more anxious to avoid the charge of homophobia than to speak out on behalf of the biblical idea of marriage. I cannot help thinking that the decision of the Archbishop of Canterbury to step down is not unconnected to the inevitable martyrdom that his office would impose on him, were he to defend the Christian conception of sexual love. On the other hand, archbishops are made for martyrdom and ought not to avoid it.

In a way, of course, the Christian view of marriage cannot really be changed by reforms of the secular law. When, in the wake of the French Revolution, the state began to take over the business of authenticating marriages, it did not affect the Christian view that marriages are made by the Church. Catholics still regard marriage as a sacrament-in other words, as a relation sealed in the presence of God, which cannot be undone merely by an agreement between the partners. The Anglican Church has never decided whether marriage is a sacrament or not; nevertheless it does not regard marriage as a secular institution, or a "church wedding" as merely a ceremonial addition to a deal whose terms are entirely exhausted by a legal contract. There is hardly a religion in the world today that does not regard marriage as an existential, rather than a contractual, move-a step out of this world of self-interested agreements, into the transcendental realm where commitments are eternal and consequences unforeseen.

The reason for this is plain. Rites of passage are inherently religious occasions. They are the "points of intersection of the timeless with time," the places in human life where the eternal meaning of what we are and do is made clear to us. Birth, coming of age, marriage, and death are metaphysical transitions, which concern not the individuals involved in them only, but the whole community of which they are a part. We all have an interest in them, and our desire to mark them with rituals and blessings is a deep sign of our commitment to each other and of our desire that the world should continue along its ancient and authorized path. That is why, for ordinary people, the introduction of gay marriage is not simply a matter of terminology but a decision that affects their whole outlook on the social world. It signifies the downgrading of marriage from status to contract. Marriage, conceived in this new way, loses its character as a social institution, through which the commitment to future generations is endorsed and made real, and becomes just another temporary negotiation.

We can hardly deny that things have been moving in this direction for some time, and that easy divorce has made secular marriage into little more than a contract in any case. Why then make such a fuss about gay marriage, which simply completes a process that has been under way since at least the middle of the 20th century? I suspect that this is the argument that will eventually prevail, and it will naturally have the effect of finally excluding children from the equation. Moreover, once that argument has prevailed it will be difficult to prevent the extension of marital rights to "polyamorous" partnerships, or to incestuous relations. It is already somewhat surprising that bigamy and incest are regarded in most Western countries as serious crimes. Maybe we have to prepare ourselves for an entirely new social order, which may be neither social nor a true order, in which any kind of sexual relationship can be transformed into a marriage, simply by signing on the dotted line. My suspicion is, however, that this change, which will be announced as a great step forward for human freedom, will in fact be experienced as a loss of true commitments, and a disinheriting of children.

Roger Scruton is a visiting scholar at the American Enterprise Institute. His latest book is The Uses of Pessimism (Oxford University Press)