I want to write something about marriage. It will only – obliquely – be about the debate on same-sex marriage, because I think that the controversy about this has created a smoke-screen around something far more important, far more profound.

I am a great supporter of marriage. Not, I have to say, for many of the usual religious or sociological reasons, although I’m sure there is a lot of merit in them. No, for me, the importance of marriage in our disintegrating society is this: at its best it provides a role model for all human community.

I’ve always been fascinated by code breaking, and the Enigma machines that were used to send coded messages in the war. It must be the mathematician in me. The Bletchley Park geniuses broke the German code by means of a crib or a cipher. That is to say, they found part of the small picture which they could understand (in this case it was a captured weather book) which allowed them to get to grips with the bigger picture.

Human relationships are written in hugely complicated code. As individuals and communities, neighbourhoods and nations, we are continually sending signals to each other which are complex and usually misunderstood. Such misunderstanding leads to mistrust, suspicion and mutual antipathy.

Relationships at every level are the key to life, but look around you. In marriages, in families, in communities, between races and between nations, we get it wrong more often than we get it right.

So we need a crib, a way in to crack the code of human relationships, a place where we can discover the way things work, where we can learn the principles and practice of relationships.

I believe that marriage unlocks the code of human relationships. It is a crib, a cipher, a key for how we can live in mutuality and collaboration. Marriage is about living co-operatively, living unselfishly, living for the good of another, living in a committed way not for number one but for others.

It is a parable of our hunger for community and our need to exist in committed relationships with others. It expresses the desire of every individual to wed our hopes, our fears, our dreams and our futures to those of another, to exist in relationship and not in isolation. It is the agent provocateur in the fight against individualism and selfishness.

And as such it is a role model for the sort of love that is at the very heart of being human. The sort of love Jesus demonstrated and taught his followers to aspire to.

So, marriage is important in human society because it is the training ground for relationships on a much bigger scale. We cannot hope for peace in the world unless and until we can build it here one-to-one with someone else. Marriage is a laboratory of the spirit. It is where we learn to love.

When I look at Syria, Nigeria, North and South Korea, at what is happening in the Middle East, and indeed the challenges we face closer to home in an increasingly fractured society, the stumbling block to progress for the human race is not so much the huge wrongs we have done to each other in the past, but the intractable entrenched attitudes which chain us to those wrongs and stop us moving on. We hold to our grievances and our bitterness about past mistakes with such ferocity!

There is no way forward without forgiveness, and there is no peace without justice. But where do we learn to forgive? Where do we begin to act out the drama of justice? With those closest to us. Until we learn it here there is no hope for the world.

We learn how to save the world in the smaller and more intimate communities we inhabit – from marriage, to our closest circle of friends, to wider groups like clubs and societies. Maybe even church.

Any arguments about the nature of marriage that focus on individual rights are missing the point. This is an institution that helps us learn how to place the needs of others first.