Steve Cooke

measuring the boundaries of our nation by the sun


Natural Law Theory and Gay Marriage

This past fortnight has seen frantic discussions on the extension of marriage to gay couples. I’ve seen repeated use of the argument against on grounds that ‘marriage is between a man and a woman for the purpose of procreation’. But why use this apparently weak argument? For one thing, it appears to outlaw marriage for infertile people , and it seems to therefore require that marriages be ended when women reach the menopause. But religious groups aren’t arguing this – so are they being inconsistent? In spite of the evidence, they say not – and the reason is routed in their belief in natural law. It’s for this reason that I’ve picked the chapter (by Knud Haakonssen) on Early Modern Natural Law from the Routledge Companion to Ethics as my reading for today.

If you recall my previous post on Plato and Socrates, I mentioned Plato’s dialogue Euthyphro. The arguments in that dialogue convincingly demolish the idea that what is morally right means what God commands (known as Divine Command Theory). The weaknesses in Divine Command Theory led to the adoption of Natural Law theory as a theory of ethics (particularly by the Catholic Church).

So what is Natural Law? The theory is that there are certain laws of nature, and things in nature have particular values and purposes (the Christian view being that these have been created by God). To determine if something is right (such as a law, or act) we ask ourselves if it is consistent with its natural purpose or the laws of nature. Probably the most famous articulations of Natural Law Theory is that provided by Thomas Aquinas – known as Thomism. Thomist thinkers were influential in the drafting of the United Nations Universal Declaration of Human Rights – so this theory is pretty pervasive in moral thought.

From a Catholic natural law perspective (I’m going to say nothing on secular natural law theories in this post) gay marriage is wrong because the natural purpose of sex and marriage is reproduction, and therefore gay sex and gay marriage are unnatural and thus wrong (along with masturbation, oral sex, and a host of other sexual practices). But, why think that the purpose of sex is purely for procreation? And on what basis is marriage thought to be natural for humans in relationships? And why should we accept the idea that using certain bits of our bodies in ways that seem to be different from their evolutionary purpose (such as our feet for playing football, our voices for singing, mouths for whistling, hands for doing handstands etc.) is morally wrong? And how should we think of bodily parts that don’t function as they should due to disability? I’m not clear that the theory has any answers to these questions.

One of the more interesting (and in my view, wrong-headed) aspects of Natural Law Theory is the idea that ethical judgements about things are made at the category level, rather than individual level. For example, we say that human beings are the rational creatures and accord them rights based on that rationality regardless of whether a particular human is rational. This idea means that a human who has no brain function should have the same rights as a fully rational moral agent. It also means that what is known as the Argument from Marginal Cases (AMC) which is often used in animal rights theory cannot find purchase. In brief the AMC points to the fact that it is inconsistent to grant rights to humans and not to non-human animals if when there are no morally-relevant characteristics that all humans and no animals possess to the relevant degree. So, if we think intelligence or rationality are the capacities that make us worthy of moral concern, then we need to explain why we should treat those humans who have them to a lesser degree than the norm with more moral consideration than those animals that have those characteristics to the same or greater degrees. Why should a Dolphin be worthy of less moral concern than anencephalic infant for example? I’ve yet to figure out why we should judge a being’s moral worth according to the category of being they are in rather than on facts about the individual being, but that’s what Natural Law theory says we should do.

Natural law theory fails because it commits Moore’s naturalistic fallacy by trying to derive ought from is. And it fails because it relies upon a questionable metaphysic that derives those moral facts from natural facts at the category rather than individual level. Additionally, Natural Law Theory says we should be able to grasp moral laws through the exercise of our reason (since this is part of our purpose as rational and free agents) – but this means that religious authorities have no special access to truth – they must supply and respond to good reasons in the same way as the non-believer. On the issue of gay marriage, I can’t say that I see this being the case – there’s a lot of irrational, bigoted and arbitrary nonsense from those opposed to letting two people who love each other publicly cement their relationship through marriage. Mini-rant over (go sign this petition for equal marriage rights).

The nice thing about reading that chapter was that not only did it explain natural law theory well, but it also provided a historical overview of its development too. This has meant that I’ve learned a little more about several important philosophical figures that I have on my list of people to discover in more depth – Grotius, Pufendorf, Spinoza, and, especially, Leibniz.