Buried away in the midst of a long apostolic denunciation of the evils of a culture soaked in idolatry is the potent little phrase παρὰ φύσιν/ para physin, meaning that which is against φύσις, against nature, natural endowments, or the natural condition (Romans 1:26). In this passage Paul was elaborating on the more spectacular failings of Gentile culture, and prominent in his assembled catalogue of evils was that of homosexuality, in both its male and female forms. He was, of course, formed by such Torah passages as Leviticus 18:22, which concerned the sexual act itself (pace the exegesis of such oddities as the Queen James Bible), so that it was not simply pederasty with young boys that was in view. (This is confirmed by his condemnation of lesbianism as equally παρὰ φύσιν as male homosexuality. For a further discussion, see here.) To gain a greater appreciation of this, it is helpful to consider sex in context—that is, to understand its function in the world.
The aphorism is true that it is “love that makes the world go ‘round”, if by “love” one means “sex”. We can easily miss this by focussing too narrowly upon human sexuality, which has become a common battlefield in the culture wars of our day. We tend to abstract human sexuality (by which we mean sexual preferences and sexual practices) from the rest of nature/ φύσις, and so miss its true and cosmic significance. For sex is not simply a matter of choosing with whom and how we humans copulate for pleasure. It is the engine that drives and sustains the world.
We see this adumbrated even in flora as well as fauna, in that even flowers need outside help in the form of pollination. The oracular Wikipedia tells me that “pollination is the transfer of pollen from an anther (male part) of a plant to the stigma (female part) of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind.” In fauna—including our human selves—the male and female parts are more obviously sexual.
The point is that sex—the combination of male and female—is necessary for life on the planet. Human sexuality, before it can be approached by way of desires and preferences, must be integrated into this overall scheme if it is to be properly understood. Our planet is sexually conditioned. Put another way, complimentary male/ female sexuality, is God’s method of planetary survival; it is “the way things are spozed to be”. That is what St. Paul meant by φύσις. And if (as I believe to be true) God created mankind through the process of evolution (the topic will not be discussed in the comments section), human sexuality is even more securely anchored in the cosmic φύσις. A Taoist might describe it as a part of the Tao, the underlying natural order of the universe to which the wise will conform.
I suggest that in describing same-sex practices as παρὰ φύσιν St. Paul was asserting the primacy of this cosmic order in the field of sexuality. First comes sex in general, and then (for us) comes human sexuality as a sub-department of it.
Since human beings are uniquely made in the image of God and are different from other animals in kind as well as degree, our sexuality is also unique. Its uniqueness consists of the fact that 1. it serves to image and reveal transcendent and heavenly realities, such as the nature of the union between Christ and His Church (see Ephesians 5); and 2. it provides the matrix for a self-sacrificing love between man and wife leading to the essential matrix for the further transmission of values—or, (in fewer syllables), it provides for the creation of marriage and of family in which children can learn how to live authentically.
I admit that there are other ways to transmit these values to children apart from the biological creation of children. One can adopt and teach the children that were born to others. One sometimes sees this is non-human nature, sometimes even across species, as when an orphan of one species is raised by a mother of another species along with her natural offspring. But as warm and inspiring as these things are when we find them on Facebook, they represent a happy departure from φύσις. Nature/ φύσις consists of male and female reproducing and then raising their own offspring. Such adoption in humanity, though happy and often commendably selfless, is a happy and usually noble exception; that which is κατά φύσιν/ according to nature, is the raising of offspring by the parents which produced them.
When one observes sex in context and as part of the cosmic Tao, one sees that it involves male and female uniting to produce offspring, and it is this union which preserves the world. For this reason marriage that involves male and female is alone kata physin, according to nature. Given that human nature is fallen and subject to passion, we also see that human nature is assailed by other desires. Some passions involve desire for sexual union with beasts, and some with minors (called “bestiality” and “pedophilia” respectively).
A more common passion involves desire for union with the same sex. This latter involves the sexualization of a natural godly relationship, that of same-sex friendship. Close same-sex friendship is inevitable and wonderful. As C. S. Lewis once pointed out, Aristotle placed it among the virtues (from his The Inner Ring). The trouble comes only when friendship is sexualized, when amicitia becomes eros.
The unnatural quality of such sexualized same-sex friendship is often obscured by the fact that in our day sexuality has already been sundered from procreation by our culture of conception. In previous ages the connection between sexual activity and procreation—and therefore the connection of human sexuality with all other sexuality in the world—was obvious. Frequent intercourse meant the eventual inevitability of babies, which provided social incentive for confining such sexual activity to marriage, which provided for the safety and raising of such offspring. Now this connection has been culturally severed, so that it is often taken for granted that sexual activity will not result in pregnancy. This serves to sever and isolate human sexuality from its cosmic context.
In our modern secular culture, sexual activity is primarily the expression of our preferences and desires, a path to personal fulfillment, having little if anything to do with the creation of family and procreation. In this brave new sexual world (which privileges male irresponsibility to the detriment of women) human sexuality is no longer regarded as an expression of sexuality in general, but is merely one more pleasurable activity, divorced from cosmic significance, transcendence, duty, or unity with the cosmos around us. Sexuality has become radically decontextualized and stripped of any significance beyond the passing pleasure of the moment.
It has, in fact, been stripped of its human significance, and is now more or less on par with animal mating. If one chooses to marry and create family, it may serve this purpose. But this purpose is now super-added to sexual activity as a matter of choice; it no longer is a part of sexuality itself. Sexuality has now been liberated and sundered not only from traditional Christian morality (which is everywhere derided), but from its cosmic context. The coincidence of human sexuality with all other earthly forms of sexuality is just that—a coincidence.
Sex is no longer a part of the Tao, the underlying natural order of the universe. We can now have designer sex, picking the gender and number and age of our partners, in the same way as we pick the colour of our cell phones. Everything about sexuality has become radically a matter of choice. Personal, sovereign, and untrammelled choice now governs not only the decision whether to have or abort children, but also our sexual partners as well. Though binary sexuality blankets and defines the world as an ingrained part of it, homosexuality deviates from this Tao, privileging human choice and passion in a way that isolates human sexuality from it and distorts it. The cosmic Tao no longer matters; all that matters is my individual desire.
What does this mean to Christians?—that a return to the cosmic Tao is a part of our faith. We believe in the Tao, in φύσις, and in nature. Sex is not just about me and the person in bed beside me. It is also a part of our participation in the cosmic Tao, and our conformity to it. God continues to create the world through sex. In His mercy He allows us to play a part in this creation.