AnalPhilosopher

Philosophers are too clever by half. When it's asserted that marriage is a childrearing institution, i.e., that the purpose of marriage is to provide for children, the retort is that not all married couples have children—or even intend to upon marrying. This is supposed to refute the assertion.

It does nothing of the sort. What it does is reflect a misunderstanding of the nature of law. Law is necessarily crude. Why do we have a drinking age, for example? Everyone knows that some people under the drinking age are mature, and therefore capable of drinking responsibly. Everyone knows that some people over the drinking age are immature, and therefore incapable of drinking responsibly. Why doesn't the law allow all and only the mature to drink? Wouldn't that be a more defensible rule?

The answer, of course, is that such a rule, whatever its intrinsic merits, is too costly to implement. An age requirement is what lawyers call a bright-line rule. Age is no more objective than maturity; it's just easier to ascertain. There are two possible mistakes here: setting the drinking age too high and setting it too low. The law tries to pick an age that correlates with maturity, an age such that most people above it are mature and most below it immature. The law trades accuracy (or precision) for ease of implementation.

Legal rules, as I say, are crude. They identify classes, not individuals. Lawyers know this and take it into account in their deliberations. Philosophers who are not also lawyers don't know it and (therefore) don't take it into account in their deliberations. We see this in the case of homosexual "marriage." When philosophers discuss the topic, they act as though all possible legal rules are equally easy to implement. Ha! A rule that restricts marriage to heterosexuals is much less costly to implement than one that restricts it to those who have or intend to have children. This is not to imply that all heterosexuals have children (although most do) or that no homosexuals have children (most do not). It's to make a distinction that correlates with what matters but is less costly to implement than alternatives.

Another way to look at it is that there's a difference between a moral argument and a legal argument. Moral arguments need take no account of institutional design, imperfect knowledge, administrative error, or information costs. Legal arguments do. Moral arguments take place in a frictionless world, so to speak. What's interesting is that liberals (including liberal philosophers) seem to understand this distinction in other contexts. They argue, for example, that even if abortion or voluntary euthanasia is wrong, it doesn't follow that it ought to be prohibited and punished by law. By the same token, there are acts (such as overtime parking) that are not wrong (i.e., not malum in se) but that ought to be prohibited and punished by law.

Morality is one thing; law is another. The issue of homosexual "marriage" is about law, not morality. It is about the world as we know it, not the world of philosophers' imaginations. It is about the real world, not some ideal world. Homosexuals are already able to marry, morally speaking. They are already able to marry, religiously speaking. The question is whether their "marriages" should be recognized by law. The answer to this moral question about the law cannot be read off, as certain philosophers appear to think, from the answer to the moral question.

Incidentally, even if I were to concede the force of the retort about childless heterosexual couples, it would not follow that all homosexuals should be allowed to marry. What follows is that all and only those with children should be allowed to marry. This would prevent all but a small percentage of homosexual couples (those with children) from marrying. It would also prevent a small percentage of heterosexual couples (those without children) from marrying. So the worst-case scenario, from the point of view of one who believes that the purpose of marriage is to provide for children, is that some small percentage of homosexuals will be allowed by law to marry.