As we now understand it, marriage is not merely the expression of a love people have for each other.

It is, or is intended as, a life-long union between two people who exemplify the biological duality of the human race, with the openness to welcoming children into the world.

Instead of the particular orientation of marriage towards the bearing and nurture of children, we will have a kind of marriage in which the central reality is my emotional choice. The revisionist case has not provided a clear and reasonable definition of marriage beyond saying that if two people want to call their relationship by that name, they should be able to by choice.

Neither does the support of TV stars, comedians, or even Bono. It is not even the case that "all the surveys say Australians want it" is a sufficient argument.

The surveys say that Australians want capital punishment.

In which case, what same-sex couples will have will not be the same as what differently sexed couples now have.

It will be called marriage, but it won't be marriage as we know it.

The argument is that applying the word "marriage" to some relationships and not to others is unequal treatment, and thus discrimination. But it is the duty of the law to judiciously discriminate and to appropriately recognise difference with, at times, unequal treatment of things that are not the same.

It isn't automatically wrong to discriminate In fact, it may be the case that offering supposedly "equal" treatment is incoherent, as it is in this case.Even when children do not arrive, the differentiated twoness of marriage indicates its inherent structure.Now, I didn't pluck this definition from the sky, nor is it simply a piece of religious teaching.Nevertheless, I don't think that the case for change is anywhere near as convincing as its proponents think it is.The case has been made almost entirely in terms of "equality" and its alleged opposite: "discrimination".One of them is this: if the Marriage Act changes, this is not the end of the world for me. I am more distressed by our inattention to children in detention, or our national greed problem, than by the possibility that the definition of marriage might be changed.