Book Review: C. S. Lewis’s Christian Apologetics: Pro & Con

It is an old saying that the best way to honor a philosopher, especially one who is no longer with us, is to take his arguments seriously. The present book attempts to do just that. It aims to give C.S. Lewis due respect by subjecting his most famous arguments to charitable yet critical examination, and to do so in a way that is accessible to general readers.

The book consists of five sections, each a debate between two authors about an argument derived from Lewis’s writings: the arguments from desire and reason, the moral argument, the Trilemma, and Lewis’s thoughts on the problem of evil.

The first section concerns the argument from desire. In various places, Lewis hints at an argument from desire for the existence of God or heaven. In Mere Christianity, for instance, he wrote that “if I find in myself a desire which no experience in this world can satisfy, the most probable explanation is that I was made for another world.” He thought there was in fact a desire which no worldly thing could satisfy. He called it Joy, and described it as a deep longing for transcendent reality that is evoked by various worldly things, but is not a desire for any of them because none can satisfy it. Lewis distinguished Joy from other, more familiar desires in two ways. First, the experience of Joy is itself a delight, something genuinely good and “more desirable than any other [worldly] satisfaction,” even when its satisfaction is absent. Second, the nature of its object is not fully revealed in the experience, though we often wrongly think that we know what the object is.

Although he had interesting things to say about the phenomenology of Joy, Lewis never stated the argument in full detail. Peter Williams explains and defends five possible versions thereof, and Greg Bassham argues that each version fails. This debate hinges on many questions, including the nature of Joy as a desire, the difference between natural and artificial desires, whether certain desires entail that possible satisfactions exist, and whether theism is the best explanation of our experience of Joy.

In the second section, Victor Reppert debates David Johnson on Lewis’s argument from reason. After briefly explaining Lewis’s argument, and its revision in light of Elizabeth Anscombe’s famous critique, Reppert ultimately defends a different argument from the one Lewis gave. He argues that features of the world—intentionality and mental causation specifically—are incompatible with the minimal metaphysical commitments of naturalism.

Johnson contends that the arguments of Lewis and Reppert fail, though his reconstruction of the former differs significantly from Reppert’s. Since Reppert does not respond to Johnson’s critique of Lewis, I will briefly comment on a portion of it.

Johnson mistakenly thinks that Lewis is concerned with the compatibility of naturalism with processes that reliably produce true beliefs, and he says that Lewis is committed to the following premiss:

If naturalism is true, then physical processes are the ultimate cause of our conclusions and mental processes are “so irrelevant you could subtract them and it would make no difference.”

Johnson notes that most forms of naturalism entail (or posit) a supervenience relation between the mental and the physical. Roughly, if mental states supervene on physical states, then mental states are a consequence of physical states and there is no change in the former without a change in the latter. Lewis, then, was wrong: it is false that, on naturalism, you can subtract the mental and nothing would change.

The problem is that Johnson, though correct, has attacked a straw man. Lewis was not committed to the second conjunct of the consequent above, namely, that mental processes can be ‘subtracted’ without any difference. He may have accepted a revision of the premiss: if naturalism is true, then physical processes are the ultimate cause of our conclusions. But to show that Lewis affirmed the original premiss, Johnson would have to show that being ultimately caused by something entails being ‘subtractable’ without any difference to the cause. But that seems absurd. The solidity of a block of ice supervenes upon the motion of its constituting molecules, and the motion of the molecules is the ultimate cause for solidity. But clearly you cannot subtract the solidity, whatever that would mean, without any difference to the molecules.

The revised premiss, Johnson says, is also false on versions of naturalism such as property dualism or mind-brain identity theory. The problem is that property dualism, depending on how it is described, is either ant-naturalistic or unable to allow for the sort of ultimate mental causality of which Johnson speaks. According to mind-brain identity theory, mental events are identical to brain events; if A is identical to B, and B is the ultimate cause of C, then so is A. But far from showing how the revised premiss is false, this insight merely restates it: on naturalism, physical processes are the ultimate cause of our conclusions. Johnson fails to show that Lewis is committed to the revised premiss or what, if anything, is wrong with it.

In the third section, David Baggett and Erik Wielenberg debate Lewis’s argument from morality for the existence of God, the bulk of which is stated in the first part of Mere Christianity. Baggett construes the argument as an inference to the best explanation and uses a version of divine command theory to explain some puzzling features of it. Wielenberg argues against divine command theory and defends a version of naturalism which he thinks can explain morality better than theism.

In the fourth section, Donald Williams and Adam Barkman debate Lewis’s famous Trilemma—liar, lunatic, or lord—argument for the truth of Jesus’s claims to divinity. Surprisingly, whereas most critics object that the argument is a false dilemma—Richard Dawkins thought that there was a fourth option, namely, that Jesus was simply mistaken in his self-attributions—Barkman accepts the validity but claims that there is sufficient reason to doubt that Jesus ever claimed to be God.

Finally, in an illuminating exchange, Philip Tallon and David O’Hara debate Lewis’s argument from The Problem of Pain. Tallon claims that Lewis is responding to the logical or intellectual problem of evil and his reconstruction of Lewis’s reasoning is thorough and compelling. O’Hara claims to argue against Lewis, but ends up arguing against a view that neither Tallon nor Lewis maintain. Lewis seems to be offering a defense against the problem of evil, but O’Hara mistakes that for a full blown theodicy, and faults Lewis for not adequately answering the emotional or existential problem of evil, which of course Lewis was not trying to do. Even though Tallon gets the upper hand, the insights from both authors make this the most valuable section.

This book is an excellent contribution to Lewis studies, and although Lewis would disavow at least some of ways these authors represent him, almost everyone—those who are disposed to dismiss him, as well as those who uncritically accept whatever he wrote—will be challenged by working through the arguments.

If you’d like to purchase C. S. Lewis’s Christian Apologetics: Pro & Con and support Apologetics315, you can purchase it here.