Pink News reports today that the Bishop of Aberdeen has asked the question “Why is it alright for a man to marry another man, but not alright for him to marry two women? If we really want equality, why does that equality not extend to nieces who genuinely, truly love their uncles?”.

The answer of course, is relatively simple. In society as it is homosexual relationships are socially acceptable. And quite right too. There are many other kinds of sexual relationships which society doesn’t accept – incest and polygamy being the obvious examples.

Now, the Bishop is obviously making the comparison intentionally because he knows this. He wants us to compare gay marriage to polygamous marriage, or incestuous marriage because he knows that most object to them. But let’s separate out the two. Let’s assume – as I hope we can – that all readers of Bright Green assume that same sex couples ought to be treated the same way as different sex couples ought to be treated. And let’s look at the two cases he mentions – incest and polyamory.

We’ve written about incest here on Bright Green before – a year ago today, as it happens. So I won’t labour the point. But whilst I am squeamish about family members hooking up, I can’t think of a good reason to ban two consenting adults from doing what they want with each other. There may, of course, be dangerous power relations between such a couple. But in the patriarchal society we live in, this would equally be an argument for banning heterosexual relationships. There may be an increased risk of genetic disease. But this would be to argue that two people who both had the same genetic disease themselves shouldn’t be allowed to get together, and that is patently ludicrous.

Polyamory is another case. Again, it makes me personally feel uncomfortable – whether it’s culturally determined, or the way I am made, I’m not into the idea of multiple partners. And again, there is of course a risk of uneven power relationships. But that I wouldn’t want to do it, and that there may in some cases be a-symmetrical power relationships at play are not relevant, for the same reasons as discussed above. There are people who choose to have long running polyamorous relationships. If everyone is consenting and happy, what’s wrong with that? Who are we to judge?

And if such relationships should be legal, then why shouldn’t we recognise them in law? The argument for civil partnerships, at least, was that marriage confers a specific set of legal rights. It’s a way of establishing in law that someone is your partner. They have specific rights if you die, or if you are in hospital, or whatever.

The argument for gay marriage is that getting married is something more than a set of legal rights. It is something cultural that we do to celebrate the kind of love Greeks call agápē – a public commitment to a life-long relationship.

Now, I am in favour both steps of the way. There seems, in our society as it is, to be a case for having a legal process whereby we say ‘this person is my partner’ – it’s a practical way of dealing with various questions all at once. I am also not opposed to marriage. I know that lots of people are, and much of what marriage has been, and usually still is, reflects and strengthens patriarchal relationships. But at its core, marriage is about having a big party at which you get together and commit to trying to make a go of a serous relationship. If people want to do that, then great.

But here’s what I don’t get. Why do we see them as the same thing? Why, in Britain do we say ‘it’s legally useful to define your partner’ and ‘unless you’re partner is a person of the same sex as you with whom you like having sex, the only way to do this is through marriage’?

Why can’t we have a process of legal attachment, in which we can say ‘this person gets to make decisions on my behalf if I’m in a coma/gets my pension/gets to see me if I’m in hospital, etc’ – a process through which we can go with as many people as we wish, and which doesn’t implicitly require us to be having sex regularly?

And why can’t we then have a separate convention – rather like birthday parties, perhaps, through which people who choose to can have parties to celebrate whatever it is about their relationships they want to celebrate?

To return to my original theme, my point is this: The Bishop asks questions about who should and shouldn’t legally be allowed to marry. In doing so, he exposes a problem with the very concept of marriage as defined in this country: why is it legally defined at all? The legal bits of marriage could equally apply to two elderly sisters living together and caring for each other as they could to a heterosexual couple. The cultural bits are not a matter for the law.

I am glad Scotland is to allow gay marriage. Even if, as some say, it’s no better than allowing gay men and lesbians to serve in a colonial American military we’d rather didn’t exist, it’s still better that LGBT people are accepted into the messed up society that we have than that they are excluded from it. But I do think we need to remember that the whole system is antiquated and designed to exclude. Hopefully, one day soon, we can establish a more sensible set of laws and norms.