Mere Christianity

Lewis believes that we can learn something valuable by the kinds of phrases people use when they quarrel. Often, one person accuses another of not meeting a certain standard of behavior, and the other person denies this or makes excuses. From this, Lewis deduces that these individuals hold a shared recognition of some kind of “Law of Nature.” Lewis points out that while this term now largely refers to things like gravity or chemistry, a universal moral code was once considered a kind of natural law itself.

The primary difference between these laws is that whereas people are simply subject to biological and natural laws, they can choose to disobey moral laws. In doing so, however, people still generally recognize that such laws exist (this is why the accused person in Lewis’s example feels obliged to deny the charge or makes excuses). Although Lewis acknowledges that there are some individuals who do not recognize a basic standard of decency (in the same way that some people are color blind), everyday experience suggests that the vast majority do; if they did not, the kinds of appeals people make to one another (e.g. arguing that someone is in the wrong) would be incomprehensible.

While some people claim that moral codes differ depending on cultural context, Lewis argues that such differences are superficial. As an example, he imagines “a country where people were admired for running away in battle, or where a man felt proud of double-crossing all the people who had been kindest to him” (6). In addition, even when people claim not to believe in a real moral code, their words and actions often suggest that they do, at least to the extent that they believe that they themselves should be treated fairly.

However, despite believing in some kind of binding morality, most people (Lewis argues all) don’t manage to fully live up to their own standards. This contradiction is for Lewis the starting point for “all clear thinking about ourselves and the universe we live in” (8).

Lewis refers to letters he has received, the writers of which fail to understand the Law of Human Nature, often suggesting that it is merely a herd instinct. Lewis does not deny this instinct, but he sees it as distinct from moral law; when someone is in distress, “feeling a desire to help is quite different from feeling that you ought to help whether you want to or not” (9).

In addition, Lewis observes that in some cases, an individual may feel torn between their instinct to help and their instinct for self-preservation. He therefore argues that there must be a third factor that resolves the conflict. This is the Moral Law, which stops the stronger instincts from automatically overriding the weaker ones (i.e. the desire for self-preservation negating the impulse to help) while strengthening the right impulse. Context can also influence what instincts predominate; people often quell their urge to fight or have sex as inappropriate in one circumstance but appropriate in another. Lewis therefore warns against a single-minded emphasis on one particular impulse. This even applies to benevolent instincts; for instance, if justice is not a consideration, people may act in an underhand manner “for the sake of humanity” (12).

Lewis also addresses the argument that the Moral Law is simply a convention, drawing a parallel to the learning of multiplication tables: if a person grew up on a desert island, then it is true that they would not know these tables, but this does not mean that these tables are artificial constructs that could be different. Lewis believes the Law of Human Nature is similar, partly because many moral ideas seem universal, but also because people routinely compare moral ideas to one another—something that would be impossible without a benchmark of “Real Morality.”

Given that people’s ideas about decent behavior can differ, Lewis acknowledges that it may sometimes seem that there is no real Natural Law. Here, Lewis highlights a distinction between differences of morality and differences of belief about facts. As an example, he responds to a question about witchcraft trials, noting that such trials no longer take place because we do not do not believe in witches; if we still believed that people were exercising malevolent powers, then we would still punish them. In other words, the underlying morality guiding our actions has not changed, even if the information we use to judge particular situations has. 

Lewis returns to his earlier point about people recognizing what is morally right but not always acting in accordance with this recognition. People, in other words, are not perfect, and Lewis stresses that this idea of human imperfection has logical implications. The law of nature means something different when applied to people than to objects such as a stone or tree. These objects are the way they are; it seems pointless to say that they ought to be otherwise, and in fact the “laws” that apply to them (e.g. gravity) are just descriptions of what they are and how they behave. For humans, however, this law refers to what they should and should not do, regardless of how they actually act.

Lewis concedes that a person might describe an object as “wrong” if it doesn’t suit their purposes, but he denies that this is what we mean by calling something morally wrong. The concept of intent makes this clear; if someone trips a person by accident, it does not evoke the same response as being tripped up on purpose. Similarly, a person’s actions may be useful but still blameworthy (Lewis gives the example of a wartime traitor helping the other side).

Lewis also denies that moral sense simply refers to actions that tend to benefit the human race as a whole. While Lewis agrees that this is a characteristic of moral behavior, it fails as an explanation. If someone asks why they should not be selfish, another person may reply that selfishness is not good for society. The first person may then enquire why they should care about society, and the other may reply “Because you ought to be unselfish” (19); the argument, in other words, is circular.

Lewis reiterates that the Law of Human Nature is not akin to a law such as gravity, but it is not “mere fancy” (20), nor can it be conflated with what is convenient. This law is not made up, but neither is it a fact (unlike our actual behavior). Lewis consequently believes that this gestures towards a different kind of reality—a real law that we did not create but feel bound by.