In my previous article, we saw that there is such a thing as sexual sanity, an objective reality with which we need to live in accord in order to be sexually sane.
Regardless of someone’s personal motive for engaging in sexual activity, procreation is its natural end. Now, the charge that such a view reduces human sex acts to mere biology might have force if producing children were the end of the story. But it’s not.
There is another purpose of sex intrinsic to making babies: the physical and emotional drawing together of spouses. Catholic theology calls these the procreative and unitive dimensions of sex.
There are two ways to see this intrinsic connection. The first sees the spousal friendship as finalizing the procreative dimension inasmuch as it makes sex a human reproductive act. The second sees how the unitive is bound to the procreative for the sake of rearing children.
Let’s start with the first way and see how the unitive makes sex properly human.
Not like the animals do
The natural end of begetting children follows from the animality of human beings. It is our sexed bodies—our reproductive organs—that order sexual activity toward procreation. We have this in common with other animals.
But we know that human sexual activity is different than animal acts of reproduction. No one in his right mind refers to two dogs “making love.” Mares don’t don lace nighties to enhance the equine sex experience. Ranchers don’t dim the barn lights and put on Barry White music for their cattle to breed.
So what is it that transfigures reproductive acts in human beings and makes them distinct in the animal kingdom? What is it that makes sex properly human?
Let reason be your guide
We can begin to get at the answer by considering other human acts. Take the act of looking at a tree. When a girl and her dog, walking along a country road, look at a tall plant with a trunk and branches and leaves, they both see a tree. But they see it in essentially different ways. The dog sees a particular thing with a certain shape and colors. The girl not only sees everything her dog sees, she sees it as tree.
In other words, the girl is able to abstract the essence or nature of what the thing is and form the universal concept of tree-ness. She is able to judge that the object before her is a tree, along with the other trees in the meadow, and reason to certain conclusions about trees—that they are material and subject to corruption, etc.
Notice that the girl’s power of sight is radically transformed by her ability to reason. As philosopher Edward Feser explains, “A human visual experience is a seamless unity of the rational and the animal…we (unlike non-human animals) conceptualize what we receive through sensation” (Neo-Scholastic Essays, 395).
Or take the act of eating. All animals share the drive to eat for the sake of self-preservation. But, far from being merely an animal activity, eating for humans is infused with rationality. Philosopher Paul Gondreau describes the human dimension of eating:
[E]ating serves a profound human function, indeed, it becomes an art, in as much as we prepare our meals with the highest of nutritional, gustatory and even aesthetic quality in mind, we observe proper etiquette when consuming our food, and, typically the preferred occasion of shared human fellowship, mealtime satisfies deep social (i.e., rational) needs (“The Natural Law Ordering of Human Sexuality to (Heterosexual) Marriage: Towards a Thomistic Philosophy of the Body,” in Nova Et Vetera, English ed. Vol. 8, No. 3 (2010): 553-92).
Human sex is more than animality
What these examples show is that our animal sentience becomes human only when integrated with our rationality. It’s the same for sex.
For sex to be genuinely human, it must be integrated with our rationality, which involves knowledge and love. And where are knowledge and love united but in friendship or interpersonal communion? The bodily union between man and woman that is ordered to begetting children therefore finds its perfection in what Aquinas calls the “indivisible union of souls” (Summa Theologiae III:29:2) that exists between spouses.
We might say that the unitive dimension of sex is to the procreative dimension what the rational soul is to the human body. Just as the rational soul makes our bodies human bodies as opposed to animal bodies or vegetative bodies, the spousal friendship (communal living) makes our procreative inclinations properly human, integrating them into the rational part of our nature.
Union for the sake of children
Unlike other species in the animal world, human infants cannot care for themselves. Nature has ordained them to be radically dependent on others for their needs, and for a long period of time.
The needs for human offspring go beyond the physical. Because humans are rational animals, children depend on other humans for what Aquinas calls “the training of the soul” (SCG III, 122. Children’s minds need to be formed in what is true. Their wills need to be directed toward what is good. They need help in learning how to live in community with others.
It is here where the union between husband and wife comes into play. Nature ordains that both man and woman be needed for the child to come into existence and then to be reared.
It is difficult for a mother to protect and provide for herself and her children when she is pregnant and/or attending to her offsprings’ needs. So, naturally, a father has to provide and protect the woman and the children with whom he has had the children. Both parents are also needed to bring their children to full maturity as members of the human race. Frank Sheed explains,
Humanity is not man or woman but both in union. A child brought up by a father only or a mother only is only half-educated. He needs what the male can give him and what the female can give him. And he needs these two not as two separate influences, each pushing him its own way, so that he moves on some compromise line that is neither, but as one fused influence, wholly human, male and female affecting him as conjoined not as competing influences (Society and Sanity, 105-106).
The bottom line
Just as a human being is both body and soul, human sex is both procreative and unitive. Nature has made it so that both aspects are essential to human sexuality.
Our sexed bodies are ordered toward the begetting of children. But because we’re human, the procreative end necessarily involves an interpersonal union of knowledge and love. The unitive dimension of sex recognizes that sex is for union with another person. But the procreative dimension recognizes that sex is for a union between a man and woman.