Almost everybody has the intuition, at some level, that the natural is good. This is why advertisers are so eager to label their products “all-natural.” At the same time, many find incredible the claim that a certain kind of act – say, the use of artificial contraception – is wrong because it is unnatural. Indeed, it is a curious fact of modern life that many of the very same people who insist that their all-natural dairy products come from hormone-free cows don’t bat an eye at dosing themselves with artificial hormones for decades on end. So there’s an opportunity here, if only we can figure out how to grab it.
People also need to see that this mode of moral judgment is in no way unique to sexual acts. The standard of goodness as naturalness applies to all moral judgments. For instance, properly understood even something like murder is an unnatural act in that it involves a violation of natural justice. So there is nothing ad hoc in seeing the unnatural as evil; rather, it reflects a metaphysics of goodness that entails not only that the unnatural is bad, but, perhaps more surprisingly, that nothing is bad except the unnatural.
The most common confusions around this point stem from a failure to recognize that there are different senses of natural, and that appeal to one of them does not necessarily invoke the others. In particular, we need to distinguish between natural as: (1) the opposite of artificial, (2) congenital, and (3) perfective, i.e. realizing what a thing most essentially is.
We often hear a reflexive reaction to the claim that some act is unnatural: so are clothes, computers, medicine, etc., and surely you don’t think those are bad! Here, obviously, unnatural means artificial. Indeed it would be ridiculous to affirm that something is wrong or bad simply because it is artificial – which is, of course, why that is not what is meant.
Rather, to say something is bad because it’s unnatural specifically means that the act is contrary to nature. Many artificial things are not contrary to nature (e.g., medicine), and some things are contrary to nature that are not artificial (e.g. bestiality). Something can be unnatural without being contrary to nature.
Loves nature. Takes contraceptives.
Consider someone born with a heart defect. There is a colloquial sense in which the defect is “natural” insofar as the victim was “born that way.” Yet in a much more important sense, the defect is unnatural. What determines what is natural is the proper activity of the organ, not its contingent condition at birth. The congenital defect is properly understood as unnatural precisely because it undermines the natural activity of the heart and thus the health of the person whose heart it is.
Contrast this with surgery done to repair the defective heart. Obviously the surgery is highly artificial in making use of advanced tools and the skill of the surgeon. Yet in a deeper sense, the reparative activity of the surgeon is natural insofar as it restores the proper function of the heart. And this is true despite the fact that the heart is “restored” to a condition that it never actually previously possessed. Here some of the most technologically advanced and artificial tools of human intelligence are put in the service of nature: to establish what should be by nature, but is not by accident.
Properly understood nature must always be the standard for medicine. It’s true that artificial means are used to “restore” natural ends. However, it’s vital to see that these artificial means are fundamentally in accord with nature. Even if the patient happened to be born that way, the congenital defect is nonetheless fundamentally unnatural because it is contrary to the natural, organic activity of the organ. This contrast should help us to see why evil is contrary to nature; evil is what’s missing, what should be there, but isn’t.
This, then, is what we mean when we oppose the good as natural to the evil as unnatural. It expresses the deeply traditional idea – found in Plato and Aristotle, and developed in the subsequent Catholic moral tradition – that nature is fundamentally teleological and what counts as good is dependent on some end (or telos) that things possess “by nature.” Thus, it is only because beings have an innate nature or essence that we can meaningfully say that any particular individual is good (insofar as it realizes that essence), or bad (insofar as it doesn’t). And this is true of all natural kinds: plants and animals, as well as human beings.
Thus an individual person is good simply to the degree that he or she manifests the characteristic perfections of rational human nature – i.e., what we call the virtues. Unlike plants and animals, however, human beings are also creatures of will and practical reason; that is, we make choices. No plant or animal can choose to act against its nature; it merely flourishes or fails. In contrast, as rational creatures we possess the freedom to choose contrary to our own nature and best interests, which means we are capable of moral evil – freely choosing against the good.
The tradition teaches us that the goodness of nature is a law written on our hearts; in our deepest recesses we cannot not know this, which is of course why so much effort is expended in the modern world to deny it. In the end, this effort is incoherent and must fail, but in the meantime, much harm is being done. And yet the widespread desire for the natural represents an opportunity. All we need to do is get people to see that “all-natural” is as good for their ethics as it is for their milk.