The Archbishop of Canterbury's speech in today's House of Lords debate

".....However, I and many of my colleagues retain considerable hesitations about the Bill. My predecessor, the noble and right reverend Lord, Lord Williams of Oystermouth, showed clearly last summer in evidence to the consultation that it contains a series of category errors. It confuses marriage and weddings. It assumes that the rightful desire for equality, to which I have referred supportively, must mean uniformity, failing to understand that two things may be equal but different. As a result, it does not do what it sets out to do. Schedule 4 distinguishes clearly between same-gender and opposite-gender marriage, thus not achieving true equality.
The result is confusion. Marriage is abolished, redefined and recreated, being different and unequal for different categories. The new marriage of the Bill is an awkward shape, with same-gender and different-gender categories scrunched into it, neither fitting well. The concept of marriage as a normative place for procreation is lost. The idea of marriage as a covenant is diminished. The family in its normal sense, predating the state and as our base community of society, as we have already heard, is weakened. I am sure that these points will be expanded on by others in the debate, including those from these Benches.
For these and many other reasons, those of us in the churches and faith groups who are extremely hesitant about this Bill in many cases hold that view because we think that traditional marriage is a cornerstone of society, and rather than adding a new and valued institution alongside it for same-gender relationships, which I would personally strongly support to strengthen us all, the Bill weakens what exists and replaces it with a less good option that is neither equal nor effective. This is not a faith issue, although we are deeply grateful for the attention that the Government and the other place have paid to issues of religious freedom. However, it is not at heart a faith issue. It is about the general social good. Therefore, with much regret—but entire conviction—I cannot support the Bill as it stands...."
[The speech - and the whole debate on the Marriage (Same Sex Couples) Bill - can be read in full here]

Archbishop Welby has already come under attack for his comment that this " is not at heart a faith issue."  I'm far from sure the critics are right; the Archbishop's words are surely meant to convey to a largely secular audience (both in the Lords' Chamber and the country at large) that the concerns he, as a representative of the Church, is expressing are by no means restricted (and therefore, for many in our society, easily and immediately dismissed) to those who share his religious faith. The point he is making here, in referring to 'the general social good' is, in essence, in its appeal to the better ordering of society based on observable patterns of necessary human social and familial relationships , a natural law argument - again, something which can be embraced, in different ways, by believer or unbeliever alike. Far from being a concession to his opponents, the Archbishop's phrase simply widens the appeal of his argument.