5.4 Ethics and Human Nature

The argument for NLT is straightforward. It rests on one factual premise and one premise that contains a value judgment, and runs like so:

Human beings have a definite nature, a set of built-in capacities.
In general it is better to follow nature than to go against it.

So we should act in such a way as to fulfill our nature as human beings and avoid violating what it is in our nature to do.

This argument has a long history, and goes back at least as far as the ancient Greek philosopher Aristotle (384-322 BCE), a student of Plato and teacher of Alexander the Great. It was revived and recast in explicitly religious terms by the great medieval Christian philosopher, and official philosopher of the Catholic Church, St. Thomas Aquinas (1227-1274). It is the foundation of Natural Law Theory and one way of defending a broader view known as Virtue Ethics, both of which equate an ethical life with a life spent realizing our potentials as well-rounded human beings.

As a quick look at the argument indicates, it is at least a valid argument. If we have a definite nature and if in fact it is better to follow that nature, then we should clearly follow our particular, human nature. We should all act in the way that is most likely to lead to the fulfillment of our natural functions. But is there anything wrong with this picture? It may seem appealing to talk about what human beings are naturally built to do, and it’s true that many people talk about how “we just weren’t meant to do that.” But the question is, how can we be so sure what a human being’s natural functions or abilities really are? And besides, doesn’t this argument seem to rest on a hidden assumption that what is natural is always better, or that what is unnatural is wrong? Can nature really be a guide for the making of value judgments?

Natural law theory assumes that the following claim is true: “Whatever is unnatural is wrong.” But is it? It is not so easy to say since the word “unnatural” has a number of different meanings. It can mean:

  • Going against the laws of nature, as in “Hot snow is unnatural.”
  • Being statistically uncommon, as in “He has an unnatural ability to remember what cards were played at the blackjack table.”
  • Being artificial, as in “Those snack foods are made only of unnatural ingredients.”
  • Violating natural functions, as in “It is unnatural for a lesbian couple to have a child with the help of a sperm bank and a team of doctors.”

Let’s look at these definitions one at a time:

  1. Violating the laws of nature is wrong. This is clearly false in that the laws of nature are just descriptions of regularities in nature and so it makes no sense to talk about violating them. Apparent violations of the law really just show us that our view of what the laws of nature are is incorrect.
  2. What is uncommon is wrong. Clearly this is not always the case – being part of the statistically defined norm is neither good not bad by itself. Rare talents are great, rare diseases not so good.
  3. What is artificial is wrong. While we might resist buying food labelled “All artificial ingredients,” and assume that natural ingredients are better than artificial ones, this claim is not in general true. There are plenty of things like artificial heart valves and limbs that have made people’s lives better and many perfectly natural phenomena like tornadoes and earthquakes that have not.
  4. What violates natural functions is wrong. This claim is really what Natural Law Theory rests on, but it also seems a bit shaky as a support for morality as we will see in a moment.

Natural purposes

The whole idea that things in nature have built-in purposes that it is somehow wrong to violate is somewhat paradoxical in that it is both intuitively appealing and difficult if not impossible to establish. It is intuitively appealing to think that things in nature have “essences” or some set of essential features that determine how they act and their roles in relationship to us. As the old saying goes, “Fish gotta swim, birds gotta fly…” This spontaneous “essentialism” is part of what psychologists have termed “magical thinking” and it seems to be built-in to the way the human mind works.9 Hence both children and early human societies tend to accept without reservation the idea that everything has a place in the world and certain internal characteristics that it would be wrong to ignore. And this makes sense to the extent that categorizing is a basic mental function that comes online first and only later are its products subject to critical reevaluation.

Until the scientific revolution finally rejected the idea that explanations of natural phenomena required specifying what the purpose, end or function of something was, this kind of essentialism was simply taken for granted as part of the explanation of anything. Aristotle was the first to explicitly formulate it as part of his account of the requirements of any explanation. According to Aristotle’s doctrine of “the four causes,” any explanation had to answer four questions about what was being explained:

For Aristotle any explanation requires specifying it’s “four causes.”

  1. What is it made of. (the “material cause”)
  2. What sort of thing it is. (its “formal cause”)
  3. How it came to be in its present state. (the “efficient cause”)
  4. What it is for or its function, purpose or goal. (its “final cause”)

This doctrine was incredibly influential and was only rejected as Galileo and other early modern scientists in the early 1500’s rejected all but the third of these as irrelevant to scientific explanation. Nevertheless, it is a central assumption of Aquinas’ account of morality that we both can and should spell out the purposes of anything in nature. If purposes are “built-in” the human beings then what we should do would be accessible in a straightforward way “by the light of reason.” However that no longer seems so obvious to modern eyes since we tend to see the purposes of things as externally imposed on them by creatures like us who use them for our purposes. Nature is no longer in our conception a place of built in forms and functions organized hierarchically in the Medieval “Great Chain of Being” or other such comprehensive views, but is more like a vast and value-neutral machine that we may be part of but that has no intrinsic values in its parts. Hence any account of value is, from this modern point of view, dependent on the free choices of those, like us, who value things. We will be seeing different conceptions of what this means in coming chapters.

In conclusion, even though it may seem tempting to appeal to nature as a guide for ethics, this strategy simply does not work. Something being natural, to use philosophical jargon, is neither necessary not sufficient for it being good or right. Likewise with something being unnatural. Even if we could spell out the “natural functions” of human beings and our parts in a way that did not beg the question, doing so would still leave open the question, as the philosopher G. E. Moore pointed out, about whether following that function was right.10 Nature provides a framework within which we can make choices that are either right or wrong or that lead either to good or evil and it is our responsibility, not nature’s to figure out which is which. Failure to recognize this is nothing but a trap – the trap of what Moore called the “naturalistic fallacy,” a mistaken form of reasoning with which we have already met.

Religion and ethics reconsidered

The ultimate conclusion of this chapter can be stated simply enough: In spite of the fact that religion often expresses moral concerns, morality and ethics are logically independent of religion. As a result we can see why it is that both Divine Command Theory and Natural Law Theory had to fail since both asserted the opposite, that without some connection to the divine, either directly or through a divinely ordered nature, ethics would be impossible. Note that this doesn’t mean that in human cultural history religious conceptions of ethics have not come first. Nor is it intended to deny that religion can be a powerful way of teaching ethical principles as it is for many people. It is just intended to mean that religion is neither necessary nor sufficient for ethics. It is not necessary in that one can be ethical without any religious belief. And it is not sufficient in that it is possible to have strong religious belief and be an awful person from a moral or ethical point of view.

  1. See Susan Gelman, “Essentialism in Everyday Thought,” American Psychological Association, accessed December 13, 2019, https://www.apa.org/science/about/psa/2005/05/gelman. for more on essentialism as a spontaneous mode of thinking.↩︎

  2. Aaron Preston, “Moore, George Edward,” Internet Encyclopedia of Philosophy, accessed December 13, 2019, https://www.iep.utm.edu/moore/↩︎