Natural disasters, natural resources, natural gas, dying of natural causes. Natural beauty, but also freaks of nature. Going back to nature and getting a natural high. Mother Nature, nature hikes, all-natural foods, natural family planning, natural childbirth. There’s the natural order, and second nature. There are natural numbers. There are all the examples I didn’t think of.
With “nature” and “natural” used in so many different ways, it’s no wonder people often misunderstand what classical natural law theorists mean when they define the good for man in terms of what is natural, and what is bad for man as what is contrary to nature.
Classical natural law theory is the idea that moral standards are derived objectively from the nature of human beings themselves.
Everyone knows, for example, that it is in the nature of a tree to require soil into which it can sink its roots and from which it can draw water and nutrients, and thus that it is good for a tree to sink its roots and bad for it to somehow be prevented from doing so.
Everyone knows that it is in the nature of a squirrel to gather nuts and the like, and to dart about in a way that makes it difficult for predators to catch it, and thus good for it to do these things and bad for it if it fails to do them. The natures of these things entail certain ends, the realization of which constitutes their flourishing as the kinds of things they are.
When we say a certain action of a plant or an animal is “good,” we mean that that action contributes to the flourishing of that plant or animal by virtue of its nature—by the kind of thing it is.
However, when we use the term “good” in the context of living things other than humans, we are not talking about moral goodness or badness. Morality involves intellect and will, which grass, trees, and squirrels all lack. That they either flourish or fail does not count as virtue or vice because they neither understand what they are doing nor can choose to behave other than the way they do.
But rational creatures like ourselves are capable of moral goodness or badness because we do have intellects and wills. The intellect can come to understand what is morally good for us by nature, and the will can either choose to pursue that or refrain from doing so. Discovery of what is objectively good for us is part of the end for which the intellect exists, and choosing what is good for us is the end for which the will exists.
Morally good action thus involves the will to do what is good for us given our nature, while morally bad action involves willing contrary to what is good for us given our nature. And to the extent that the intellect knows what is good for us, we are culpable for these good or bad actions. To will to do what is “natural” thus means, in classical natural law theory, something like: to will to do what tends toward the realization of the kind of things we are. And to will to do what is “unnatural” frustrates these ends and diminishes human flourishing.
If a squirrel were rational, it would be natural and good for it to will to escape predators and to gather nuts for the winter, and unnatural and bad for it to will to offer itself up to predators and to eat only toothpaste or stones. And the latter would be unnatural and bad for it whatever the reason it willed these things—brain damage, genetic anomalies giving rise to odd desires, bad squirrel upbringing, squirrel peer pressure, the influence of squirrel pop culture, arguments from squirrel philosophers who were hostile to natural law, or whatever.
But to “act in accordance with nature” is not the end of the story.
In commending what is in accordance with our nature, natural law theorists do not mean “natural in the sense of commonly occurring in the ordinary course of nature.” All sorts of things commonly occur in the ordinary course of things that tend to frustrate our nature—injuries, diseases, floods, earthquakes, and, for that matter, immoral choices. Hence, when people say that it is “natural” for a child to be selfish or for a man to have a roving eye, there is a sense in which this is true, but it is not the sense that is operative in natural law theory. A goldfish will “naturally” tend to keep eating the food you drop into its tank even after it is full, but that hardly fulfills its nature in the relevant sense (since it will overeat and thereby kill itself). Similarly, we have, given our limited nature as created things, inherent susceptibilities to defects and failures of various kinds—overeating, overreaction to injustices, excessive fear in the face of danger, sexual vices, bodily injury, the contraction of various diseases, etc.
For the same reason, the natural law theorist does not mean “natural in the sense of flowing from a deep-seated tendency.” A deep-seated tendency could result from habituated vice or hereditary defect, either of which would be contrary to nature in the relevant sense. A predisposition to alcoholism or heart disease doesn’t help the person who has it to realize the ends inherent in his nature, even if such a predisposition has a genetic basis.
The natural must also be carefully distinguished from the supernatural. The “supernatural” is above or additional to our nature and the ends inherent in it. Although the knowledge of God is something of which we are capable given our nature, and which we require for our complete flourishing, the intimate, “face-to-face” knowledge of God that is the beatific vision is not “natural” in the sense we are discussing. That is rather a matter of grace, of being raised to an end higher than what we would be due or capable of given our nature.
Is the natural law a law given by God? Yes and no. Yes insofar as the natural law reflects the natures of things, and God, as creator, is the author of things and their natures. But the natural moral law is to that extent no different from what was said above about grass, trees, and squirrels. You don’t need to study theology in order to find out what is good or bad for grass, trees, and squirrels; indeed, you could be an atheist and know it. And the same thing is true for what is good or bad for us given our nature.
The natural law differs, then, from law that is directly given by God via a special revelation, as with the law given to Israel through Moses. It is, in principle, available to all men simply by virtue of being rational and capable of knowing what is good or bad for them given their distinctive nature.
So, for the natural law theorist, certain things are “natural” for us in the sense of tending to fulfill those ends of which the realization constitutes our flourishing as the kinds of thing we are. But perhaps it is also natural for us—in a different sense, the sense of being a weakness to which we are prone given the limitations of our nature—to want to deny that we are subject to natural law. To that extent, at least, we are all natural lawyers, but of a rather sleazy kind—seeking, not justice, but to find any way we can to get ourselves off the hook.
Edward Feser teaches philosophy at Pasadena City College and is the author of The Last Superstition: A Refutation of the New Atheism, Aquinas: A Beginner’s Guide, Scholastic Metaphysics: A Contemporary Introduction, and many others.