THE Supreme Court ruled last week that a heterosexual couple were being discriminated against because they were unable to have a civil partnership (News, 29 June). The barrister acting for the couple claimed that they had “deep-rooted and genuine ideological objections to marriage”, not least on the grounds that marriage was “historically heteronormative and patriarchal”. The ruling makes likely a change in the law, opening civil partnerships to all.

Civil partnership began as a particularly British social reform, designed to extend the financial advantages and legal protections of marriage to same-sex couples. It also conferred social recognition and the elusive but important virtue of respectability.

Some of the arguments presented to the Supreme Court last week were strange, to say the least. It can hardly be held that marriage is still heteronormative and patriarchal when gay marriage is permitted — hence the barrister had to add the word “historical”.

But, in spite of this caveat, the impression was created that marriage is an unchanging and inflexible institution, a barrier rather than an enabler of human well-being.

The reality, of course, is that marriage has changed through the centuries and continues to change. Once largely about inheritance and property rights, marriage came to be regarded principally as the proper context for family life. Now, it is often seen chiefly as the ideal outcome of personal love and commitment. Compare the BCP marriage service with Common Worship, and the differences are obvious. Since 1836, there has been the alternative of civil marriage, which has no religious overtones.

Civil partnerships differ from marriage in that they say nothing about sex. The law on gay marriage also used neither of these concepts. But, in other respects, the difference between civil marriage and civil partnership is not as great as it might appear to be, especially where couples make some kind of declaration of commitment to one another. Civil partnerships are constituted by signing a contract between individuals, but they are ceremonies in their own right.

The Supreme Court ruling exposes the conflict between diversity and equality. Diversity could have accepted same-sex civil partnerships as an equal-but-different arrangement to marriage. This would have been helpful to the Church and would have given civil partnerships a chance to prove their worth, or otherwise.

But equality demanded the abolition of difference, hence the speedy introduction of gay marriage. But this reintroduced inequality, since same-sex couples currently have greater choice than others about how their commitment is expressed.

The Supreme Court’s judgment paves the way for the inevitable new legislation. In an ideal world, of course, we would want both diversity and equality. But this is just one instance of the way that we cannot necessarily have both.

The conflict of principles constitutes one of the biggest moral and political problems of our time.