Mere Creationism: C. S. Lewis and Moral Evolution

C. S. Lewis’ widely popular book, Mere Christianity, begins with a moral argument for the existence of God. Lewis argues that our intuition that there are objective morally right and wrong behaviors indicates that there is an objective moral law that exists independent of our belief in it, pointing to the probability that a being such as God must exist to have created such a law.

In Chapter 2 of Book 1, Lewis addresses some objections to this argument. Firstly, Lewis points out that one can argue that what he calls “Moral Law” is just a herd instinct, where some animals are inclined to do things to benefit others within their group. This is undoubtedly a real phenomenon, but Lewis does not consider this a possible explanation for the intuition that there are moral laws. Lewis says the following:

“… we sometimes do feel just that sort of desire to help another person: and no doubt that desire is due to the herd instinct. But feeling a desire to help is quite different from feeling that you ought to help whether you want to or not. Supposing you hear a cry for help from a man in danger. You will probably feel two desires–one a desire to give help (due to your herd instinct), the other a desire to keep out of danger (due to the instinct for self-preservation). But you will find inside you, in addition to these two impulses, a third thing which tells you that you ought to follow the impulse to help, and suppress the impulse to run away. Now this thing that judges between two instincts, that decides which should be encouraged, cannot itself be either of them. You might as well say that the sheet of music which tells you, at a given moment, to play one note on the piano and not another, is itself one of the notes on the keyboard. The Moral Law tells us the tune we have to play: our instincts are merely the keys.”

Mere Christianity, 9-10

For the sake of argument, let’s take Lewis’ schema as being basically accurate: we sometimes have two competing instincts – the instinct to preserve the life of another, and the instinct to preserve our own life. When these instincts are in conflict, something must mediate which action we are going to take. Lewis argues that this mediating factor cannot itself be an instinct, and uses several analogies to make this point (the distinction between the tune and the notes is only the first of several). However, none of Lewis’ analogies address a rather natural restatement of the original objection: why can’t there be a third instinct that mediates between other instincts? Of course, Lewis is correct in pointing out that whatever makes us choose between two instincts cannot itself be one of the two, but he doesn’t bother to address the obvious possibility that it could be a different instinct altogether, but still an instinct nonetheless. The idea that such an instinct exists, with some element of cultural mediation, is a concept that has been established by scientists in recent years: see the works of David Sloan Wilson, Richard D. Alexander, and David C. Lahti, as well as many others. (I have attached two videos that I have found to be helpful for laypersons who might have difficulty comprehending how natural selection has shaped moral evolution).

Video posted to YouTube by Meta Mentality

Video posted to YouTube by unseenstrings

C. S. Lewis does not present himself as a creationist with respect to physical, biological evolution. What is more, Lewis makes several references to biological evolution in Mere Christianity that indicate that he is very open to the possibility (see especially Book 4, Chapter 11). However, Lewis’ argument from morality appears to depend upon a creationist logic: X cannot be explained by natural selection, therefore it is the result of a special act of creation. But where the Young Earth Creationist would insert (X = complex organisms), Lewis inserts (X = Moral Law). And for both the creationist and C. S. Lewis, the assertion that natural selection cannot account for the phenomenon is unjustified.

Some Critiques of My Argument

I have had 3 responses to the arguments presented in this post that I would like to address. I address them in the order that they have been presented to me by a friend who was generous enough to carefully read and thoughtfully respond to my argument.

1. Am I Misrepresenting Lewis’ Argument?

The first critical response that I have received claims that I have misunderstood the point that Lewis is attempting to convey. It is claimed that Lewis is not saying that moral universals are not the product of evolution, but rather he is arguing that such moral universals cannot be objectively true if they are not given some higher authority. William Lane Craig articulates this view of moral evolution well:

Video posted to YouTube by drcraigvideos

Craig’s response to the evolutionary objection to the moral argument is very good. However, it is clearly not the response that Lewis is making. It is true that Lewis’ broader argument focuses on the necessity of God for the objectivity of moral truths, however, a careful reading of Lewis’ response to the evolutionary objection categorically demonstrates that Lewis is engaging in the creationist-style argumentation of which I accuse him.

When Lewis frames his response to the evolutionary argument by saying, “feeling a desire to help is quite different from feeling that you ought to help whether you want to or not,” we can clearly infer that the proceeding argument is an attempt to demonstrate that the feeling that there are moral “oughts” cannot be a product of group-level natural selection. And when we look at the similitudes Lewis presents, it is again clear that this is Lewis’ argument. When Lewis says that moral law is like the tune, and the instincts are like the keys on a piano, it is obvious that he is arguing that the feeling of a moral ought cannot be the product of evolution, even if the specific behaviors were produced for evolutionary reasons.

2. Can I Realy Prove That Morals Are a Product of Evolution?

Once it is recognized that Lewis is dismissing evolutionary explanations for moral intuitions, some will object that the evidence for moral evolution is not strong. I happen to think the evidence is very strong, although I am by no means an expert on the topic.

However, whether or not the evidence is strong is somewhat beside the point, for even if the evidence were weak, an evolutionary origin of morals only needs to be possible in principle for the argument to hold water. Remember, in order for Lewis’ argument to prove that God exists, we must accept that our moral intuition requires the existence of God. Thus, if it is even possible that an evolutionary explanation of morals is true we can already reject the God hypothesis, so long as the evolutionary explanation has not been disproven outright.

3. Is It Fair to Criticize Lewis for Not Knowing About Moral Evolution?

Now suppose that one concedes that Lewis is arguing against an evolutionary theory of moral intuitions, and acknowledges that the evidence for such an evolutionary theory is strong or at least valid. Such a person might argue that it is unfair to criticize Lewis for making this mistake because he lived a long time before the evidence for moral evolution was as strong as it is today.

This is simply not the case. Charles Darwin argued that moral systems might be a product of natural selection in The Descent of Man, published nearly 100 years before C. S. Lewis wrote Mere Christianity. And as I mentioned previously, Lewis’ argument is fallacious even if the evidence is poor, so it doesn’t matter that the evidence is now better than it was when Lewis was around. The flaw is in the logic Lewis employs in his argument, and the mere possibility that evolution is a product of morals invalidates Lewis’ arguments against evolutionary explanations of moral intuitions.


Alexander, Richard D. The Biology of Moral Systems. Aldine Transaction, 1987.

Lahti, David C., Weinstein, Bret S. (2005). “The Better Angels of Our Nature: Group Stability and the Evolution of Moral Tension.” Evolution and Human Behavior. vol. 26, no. 1: pp. 47-63.

Lewis, C. S. Mere Christianity. HarperOne, 1952/2001.

Wilson, David Sloan. Darwin’s Cathedral: Evolution, Religion, and the Nature of Society. University of Chicago Press, 2002.

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