There are different ways of applying natural law to the issues of pre/extra-marital sex and homosexuality. Most textbooks mention Aquinas and perhaps Humanae Vitae, and in fact these are on the spec. But you need to go somewhere a bit more philosophically meaty to get a sense of a fully integrated argument. This is where I like to go to John Finnis. Finnis, in a paper entitled ‘Law, Morality and Sexual Orientation’ published in 1994, traces the development of a view with roots in Ancient Greek thought about the intrinsic desirability of marriage as a chastely exclusive union. In parallel with this goes the clear rejection in the Platonic-Aristotelian view of all homosexual conduct as non-marital and unworthy of the human being.
(This will probably come as a surprise to some who have imbibed the idea that the Ancient Greeks were all for homosexual behaviour, but this is not the case.)
Finnis presents an argument found in Grisez and others that, far from being the ends of marriage, procreation and friendship are an experience of the intrinsic good of marriage. Marriage is a basic good, and therefore not instrumental of anything, including procreation. This overcomes one of the key objections made to Natural Law arguments about homosexuality – why are knowingly non-procreative sexual acts within marriage (eg when a woman is post-menopausal or pregnant) acceptable, but non-procreative acts between homosexual couples unacceptable?
In Finnis’ own words: “ It took a long and gradual process of development of doctrine, through the Catechism of the Council of Trent, the teachings of Pius XI and Pius XII, and eventually those of Vatican II to bring the tradition to the position that procreation and children are neither the end (whether primary or secondary) to which marriage is instrumental (as Augustine taught), nor instrumental to the good of the spouses (as much secular and “liberal Christian” thought supposes), but rather : Parenthood and children and family are the intrinsic fulfilment of a communion which, because it is not merely instrumental, can exist and fulfill the spouses even if procreation happens to be impossible for them.”
We can then apply this to all the cases of extramarital and non-reproductive sex featured on the spec. Marriage is “the organising good for the whole domain of human sexuality” as Finnis puts it. Thus, just as adultery violates the “communion of persons in marriage which is a fundamental human good” as Pope John Paul IIs encyclical Veritatis Splendor puts it, so all instances of homosexual conduct are “radically incapable of participating in, actualising, the common good of friendship”.
So in fact the discussion around the issues of extra-marital and homosexual sex can be seen in terms of an understanding that when basic goods such as marriage are undermined either through adultery and divorce, or through homosexual conduct, the good of individuals and society is eroded, as society is built on the communion of friendship and transmission of life that constitutes marriage.
So the discussion which might be had with a question such as ‘Natural Law approaches to sexual ethics are flawed’ would involve properly articulating what the most sophisticated versions of Natural Law have had to say on the subject. Some of what passes for discussion of this by people who should know better (eg RS Teachers) is not going to be very helpful in evaluating the subject.
So which approach is better? Can you argue that Mill or Kant or Bentham’s approach to sexual ethics is better? I would love to hear your comments.