What can we say to someone who refuses to acknowledge nature’s blueprint for sexual sanity? Someone who, like the character Skipper from the 2014 movie Madagascar Penguins, says, “You know what? I reject nature.”
I answer that we should reverence nature’s blueprint for sex for goodness’ sake. And I don’t mean this in the idiomatic sense of expressing frustration, but quite literally for the sake of doing what is good.
First, let’s think through what the good is. What is good for a living creature is determined by the purposes for which its natural faculties and capacities exist. For example, the roots of an oak tree exist for the sake of providing the tree with nutrients and stability. Anything that frustrates the achievement of these ends, such as chopping off the roots or feeding them poison, would be bad for the tree—that is to say, it would impede the tree from being what it’s supposed to be, given its nature.
By contrast, anything that helps the roots of the tree to achieve these ends, such as water, fertilizer, and light, is good for the tree. It helps the tree flourish.
And these facts about what is good and bad for a tree are true no matter how we feel about them or what we choose to accept or reject.
Human beings are no different. Our faculties and capacities—whether those that we share with the animal kingdom (e.g., sight, hearing, digestion, etc.) or those that are unique to us as rational animals (intellect and free will) are ordered to what makes human nature flourish.
The same line of reasoning applies to our sexual faculties. If these exist for the sake of some end, which means something good for our human nature, then it can’t be good for us to use them in a way that subverts that end.
Since, as we can discern through observation, the ends toward which nature orders our sexual faculties are procreation and unitive love, what is good for us sexually are acts that serve these ends. Acts contrary to them (e.g., masturbation, contraception, fornication, adultery, etc.), on the other hand, are feeding poison to the roots.
The question now is, “How does one get from a description of natural goods to a moral good?” Or to use philosopher David Hume’s language, how do we get from an is to an ought?
It might seem at first that to invoke the natural ordering of our sexual powers (called sexual teleology, coming from the Greek word telos, which means end or goal) to determine moral precepts would be to commit the fallacy of illicit process, which introduces something in the conclusion, in this case an ought, that is not in the premises. This type of fallacy is called the naturalistic fallacy.
But no such fallacy is committed. The movement from a natural is to a moral ought is based on St. Thomas Aquinas’s first and most fundamental moral precept: that one ought to do good and avoid evil.
Aquinas explains that just as being is the first thing that falls under the apprehension of the speculative reason (reasoning to what is), the good is the first thing that falls under the apprehension of the practical reason, which is directed toward action. For Aquinas, this must be the case, since every human “acts for an end under the aspect of good” (Summa Theologiae I-II:94:2).
What Aquinas means here is that whatever human beings do, they do because they think it will be good for them in some way. Even the murderer’s end may be the elimination of an enemy, or the satisfaction of his anger; even the thief aims for the good of his victim’s money.
Since all men seek the good, whether real or merely apparent, Aquinas concludes that seeking the good is the first principle of practical reason. From this he derives the first moral precept: “Good is to be done and pursued, and evil is to be avoided.” All other precepts are based on this primary one.
Herein lies the key for deriving moral precepts from the natural ordering of human faculties, and in particular the sexual faculty. If we ought always do what is good, and the good is determined by the ends toward which our faculties are ordered, then we ought to always use them in a way that is consistent with their ends and avoid using them in a way that frustrates those ends.
To use our sexual faculties in ways opposed to their ends is to act irrationally, since reason tells us what is good for our nature. This is contrary to our human dignity, since the ability to act in accord with reason is the identifying mark of a human being. It is also to act immorally, since we are not doing what we ought. Finally, it is to harm our chances for flourishing, for succeeding in the art of being human.
To be in accord nature’s design for human sexuality, then, is to give ourselves the best chance to be happy. If you think it through, that’s something everyone should want.