C.S. Lewis Misunderstood and Misrepresented David Hume

Tapping My Hume Sign #2

In my previous post, I dispelled the argument that Hume’s argument in Of Miracles is circular. You can find a summary in this footnote.¹ C.S. Lewis likely popularized that argument in chapter 13 of his book Miracles.²

The chapter is short, thankfully, however it’s wrong on so many points that it’s not a useful resource to engage Hume’s argument. If you read it, you will be actively misled.

I’m not going to rebut everything Lewis has to say about miracles or Hume; my intent is to cast enough doubt that Lewis understands Hume; I want to convince you to look elsewhere for thoughtful counterarguments to Hume.

Hume’s Laws of Nature Are Not The Same As the Principle of the Uniformity of Nature

Lewis conflates Hume’s principle of the uniformity of nature with his formulation of natural laws.

“According to Hume, probability rests on what may be called the majority vote of our past experiences. The more often a thing has been known to happen, the more probable it is that it should happen again; and the less often the less probable. Now the regularity of Nature’s course, says Hume, is supported by something better than the majority vote of past experiences: it is supported by their unanimous vote, or, as Hume says, by ‘firm and unalterable experience’.”

This is wrong. Hume’s probability rests on the principle of the uniformity of nature, not the “majority vote” of natural laws. Here’s how these two ideas are different:

The principle of the uniformity of nature is the assumption that nature is uniform. For Hume, whenever we investigate the world, we must assume it acts in a uniform manner. We assume the uniformity of nature out of custom and habit, and because scientific investigation would be impossible without it.

From Part 1 of his essay Of Liberty and Necessity, found in his first Enquiry:

“It seems evident, that, if all the scenes of nature were continually shifted in such a manner, that no two events bore any resemblance to each other, but every object was entirely new, without any similitude to whatever had been seen before, we should never, in that case, have attained the least idea of necessity, or of a connexion among these objects. We might say, upon such a supposition, that one object or event has followed another; not that one was produced by the other. The relation of cause and effect must be utterly unknown to mankind. Inference and reasoning concerning the operations of nature would, from that moment, be at an end; and the memory and senses remain the only canals, by which the knowledge of any real existence could possibly have access to the mind. Our idea, therefore, of necessity and causation arises entirely from the uniformity, observable in the operations of nature; where similar objects are constantly conjoined together, and the mind is determined by custom to infer the one from the appearance of the other. These two circumstances form the whole of that necessity, which we ascribe to matter. Beyond the constant conjunction of similar objects, and the consequent inference from one to the other, we have no notion of any necessity, or connexion.”

When Hume and other skeptics assume the principle of the uniformity of nature, it’s not a conclusion that they inferred from evidence, nor is it an assumption of truth. As Bill Vanderburgh explains, the principle is “merely a regulative ideal for investigation of the world, rather than a supposed truth about the world.”

Natural laws are different. They are probabilistic proofs that are so well supported that they function as laws. They can be overturned, but to do so, we need sufficient conflicting probabilities that downgrade it to a mere convincing probability.

Here Hume explains proofs and probabilities in Of Miracles:

“A wise man, therefore, proportions his belief to the evidence. In such conclusions as are founded on an infallible experience, he expects the event with the last degree of assurance, and regards his past experience as a full proof of the future existence of that event. In other cases, he proceeds with more caution: He weighs the opposite experiments: He considers which side is supported by the greater number of experiments: To that side he inclines, with doubt and hesitation; and when at last he fixes his judgment, the evidence exceeds not what we properly call probability. All probability, then, supposes an opposition of experiments and observations, where the one side is found to overbalance the other, and to produce a degree of evidence, proportioned to the superiority. A hundred instances or experiments on one side, and fifty on another, afford a doubtful expectation of any event; though a hundred uniform experiments, with only one that is contradictory, reasonably beget a pretty strong degree of assurance. In all cases, we must balance the opposite experiments, where they are opposite, and deduct the smaller number from the greater, in order to know the exact force of the superior evidence.”

And later:

“A miracle is a violation of the laws of nature; and as a firm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as entire as any argument from experience can possibly be imagined…There must, therefore, be a uniform experience against every miraculous event, otherwise the event would not merit that appellation. And as an uniform experience amounts to a proof, there is here a direct and full proof, from the nature of the fact, against the existence of any miracle; nor can such a proof be destroyed, or the miracle rendered credible, but by an opposite proof, which is superior.”

So Lewis is off to a bad start.

He thinks Hume infers the uniformity of nature, when Hume simply presumes it. For Hume, the reason why we assume the uniformity of nature is because it’s a habit or custom, it’s psychologically inevitable (just as it’s psychologically inevitable to draw inferences), and we can’t draw inferences without it. Keep this in mind for the end!

Expressed visually:

Hume’s Theory:

From the Principle of Uniformity → Formulation of Probability → Probabilistic Natural Laws

Lewis’s Misunderstanding of Hume

Hume’s Formulation of Probability (“The Unanimous Vote”) → The Principle of Uniformity → Natural Laws That Resemble Edicts

The charitable interpretation of Lewis’s confusion is that the nuances of Hume’s position on laws of nature and the principle of uniformity were not obvious on a cursory reading of his works. Maybe Lewis just missed it. What’s more, the Scotsman was misunderstood by his contemporaries, and he wrote when probability theory was in its infant stage, so philosophers for the last few hundred years have read him in the light of more mature probabilistic theories, thus misreading him.

So, to this point, I’m willing to cut Lewis some slack in misreading or misunderstanding Hume, but as we will see, I think it’s more likely the case that he simply didn’t try to understand Hume.

Circularity, Balancing Probability, And Wisdom

Lewis puts the (false) circularity argument on display.

“There is, in fact, ‘uniform experience’ against Miracle; otherwise, says Hume, it would not be a Miracle. A miracle is therefore the most improbable of all events. It is always more probable that the witnesses were lying or mistaken than that a miracle occurred. Now of course we must agree with Hume that if there is absolutely ‘uniform experience’ against miracles, if in other words they have never happened, why then they never have. Unfortunately we know the experience against them to be uniform only if we know that all the reports of them are false. And we can know all the reports to be false only if we know already that miracles have never occurred. In fact, we are arguing in a circle.”

I’ll once again tap the sign on this argument, but I will also add some nuance.

The reason why the laws of nature are held to higher respect than miracle claims isn’t just the inherent improbability of miracles or the rigidness of the laws of nature, but that when balancing two probabilities, the laws of nature are always more convincing than testimony. But that’s not the only reason Hume considers miracles and their testimony false.

Falsehood And Balancing Probability

Hume’s language of falsehood is admittedly confusing and blunt for modern philosophy language, but much more nuanced than Lewis understands.

Let’s say hypothetically, you told me that you sprouted wings to commute to work. Should I believe you? Should I investigate your claim? Would it be wise, upon hearing such claims and similar claims, that a wise person should believe or investigate them? Merely on the grounds of testimony?

Of course not!

When Hume says that miracle testimony and miracles claims are false, it’s an inference. If you have the experience of investigating miracle claims, as many skeptics do,³ you’ll find an overwhelming majority false, if not all of them. From that experience, you’re justified in assuming future miracle testimony is false and compromised, even if you haven’t examined all testimony directly.

Again, that may seem rash on first glance, but remember, it’s not just one datapoint that we dismiss the testimony as false. Rather, it’s the weight of the combined proof of high quality laws of nature and the proof or high probability of bad miracle testimony against the low probability of good miracle testimony.

Probability Weight Illustrated:

The Proof of The Laws of Nature + The Proof of Bad Miracle Testimony > The Probability of a “Good” Miracle Testimony⁴

Wisdom

That’s not to say we can never revise our understanding of natural laws based on the sheer volume of contravening testimonial evidence (but more importantly, additional non-testimonial evidence), or that we can’t suspend belief in natural laws to critically examine them, but that miracle testimony (as a matter of fact) is not of the quality that justifies doing so.

There are countless implicit laws of nature that frame our experience. It would be capricious of us, on the grounds of low-quality evidence such as religious testimony, to question some of them and not others. Wise people just don’t do this.

So when Hume calls miracles and miracle testimony false, it’s not because he’s going after every miracle testimony case-by-case like James Randi. Rather, he is morally certain that it is false, given the weight of the evidence in both directions (in favor of the uniformity of nature, against the truth of religious miracle testimony). I think most people who hear miracle testimony from religious traditions that aren’t their own internalize this methodology.

There’s an aphorism that one should keep an open mind, but not so open that their brain falls out. That is the essence of Hume’s account of wisdom. We all have limited time and cognitive resources, and to question fundamental assumptions of how we understand the world on such measly evidence is a waste of time. Wise people don’t do that. Because of how improbable miracles and incredible miracle testimony are, wise people simply consider such accounts false.⁵

Is Hume’s language of falsehood as even handed and open as contemporary scientific or philosophy peer reviewed articles? No. But it’s not closed minded or presuppositional: it makes sense if you understand Hume’s vocabulary of probability.

Lewis Confuses His Misunderstanding With Hume’s Inconsistency

Lewis continues to misunderstand Hume’s conception of natural laws and the principle of the uniformity of nature:

The whole idea of Probability (as Hume understands it) depends on the principle of the Uniformity of Nature. Unless Nature always goes on in the same way, the fact that a thing had happened ten million times would not make it a whit more probable that it would happen again. And how do we know the Uniformity of Nature? A moment’s thought shows that we do not know it by experience. We observe many regularities in Nature. But of course all the observations that men have made or will make while the race lasts cover only a minute fraction of the events that actually go on. Our observations would therefore be of no use unless we felt sure that Nature when we are not watching her behaves in the same way as when we are: in other words, unless we believed in the Uniformity of Nature. Experience therefore cannot prove uniformity, because uniformity has to be assumed before experience proves anything.

And mere length of experience does not help matters. It is no good saying, ‘Each fresh experience confirms our belief in uniformity and therefore we reasonably expect that it will always be confirmed’; for that argument works only on the assumption that the future will resemble the past—which is simply the assumption of Uniformity under a new name. Can we say that Uniformity is at any rate very probable? Unfortunately not. We have just seen that all probabilities depend on it. Unless Nature is uniform, nothing is either probable or improbable. And clearly the assumption which you have to make before there is any such thing as probability cannot itself be probable. The odd thing is that no man knew this better than Hume. His Essay on Miracles is quite inconsistent with the more radical, and honourable, scepticism of his main work.

I’m not going to beat the dead horse about how Lewis confuses laws of nature and principles of uniformity again, but I will point out that Lewis demonstrates, again, a deep confusion about Hume’s project.

His misunderstanding is one of the common misunderstandings of Hume. Many presume that because Hume thinks there’s no logical justification for a cognitive tool, that using that tool isn’t justified at all. Because there’s no logical foundation for induction, we can’t use induction. Because we can’t get an “ought” from an “is” in ethics, we cannot make sense of morality, or there’s no sense in creating or understanding moral rules, etc. And so on.

What Hume is really trying to say is that matters of fact are important to understand and make decisions about the world, more than his contemporary rationalists believed.

Hume is a skeptic in that he likely agreed with many radical skeptical conclusions, that we can’t be completely certain about many foundational truths. But Hume also thought that it was unfeasible to live one’s life this way. His philosophical project of mitigated skepticism was as much about tempering the zeal of those with unjustified certainties as it was to give assurance to radical skeptics that one could be morally certain that, say, that the sun would rise tomorrow. To learn more, read his essay on skepticism.

But Lewis instead misrepresents Hume as a rudderless radical skeptic. I’m not quite sure what Lewis even means when he says Of Miracles is less skeptical than his main work, because I don’t see how you can read his main work and conclude he’s a radical skeptic. The fact that Lewis thinks this when Hume has an essay criticizing radical skepticism demonstrates a lazy, basic misunderstanding of Hume.

Getting Hume Completely Wrong

But there are more errors!

The question, ‘Do miracles occur?’ and the question, ‘Is the course of Nature absolutely uniform?’ are the same question asked in two different ways. Hume, by sleight of hand, treats them as two different questions. He first answers ‘Yes,’ to the question whether Nature is absolutely uniform: and then uses this ‘Yes’ as a ground for answering, ‘No,’ to the question, ‘Do miracles occur?’ The single real question which he set out to answer is never discussed at all. He gets the answer to one form of the question by assuming the answer to another form of the same question. Probabilities of the kind that Hume is concerned with hold inside the framework of an assumed Uniformity of Nature.

When asked if miracles occur, contrary to Lewis, Hume would probably say “I don’t know, but it would be unwise to believe they do.” If asked whether nature was absolutely uniform, he would probably say “I don’t know, but I can’t help but believe it, and science wouldn’t be possible without assuming it.”

Again, Hume is a skeptic! Skeptics are open about not knowing things! He is more concerned about the question of whether it’s wise to believe that a miracle happened than if a miracle really happened.

For example, it could be the case that numerous bunnies are resurrected every year in the forest, but no one is around to see them, and there’s otherwise no evidence of this occurring. Even though this event would be miraculous and true, it would be unwise to believe it, because there wouldn’t be good evidence, as it’s unwise to believe in things without evidence!

The fact that Lewis thinks Hume is answering the question “do miracles occur” and not “would it be wise to believe miracles occur” is another fundamental misreading of Hume. Once again, Of Miracles is a work of epistemology, not ontology or metaphysics. If you think Hume is making an ontological or metaphysical argument and not an epistemological one, you are deeply confused.

Lewis The Rambling Smooth Talker

When first writing this post, I almost omitted this passage, because I viewed it as Lewis opining about miracles in a way unrelated to Hume. Upon a re-read, I thought it demonstrated how close Lewis was to understanding Hume. I also thought that it could be interpreted that I’m omitting Lewis’s words that undercut my conclusion that he doesn’t know Hume. After all, he’s talking about how Hume’s probability relies on the uniformity of nature, right?

“Probabilities of the kind that Hume is concerned with hold inside the framework of an assumed Uniformity of Nature. When the question of miracles is raised we are asking about the validity or perfection of the frame itself. No study of probabilities inside a given frame can ever tell us how probable it is that the frame itself can be violated. Granted a school timetable with French on Tuesday morning at ten o’clock, it is really probable that Jones, who always skimps his French preparation, will be in trouble next Tuesday, and that he was in trouble on any previous Tuesday. But what does this tell us about the probability of the timetable’s being altered? To find that out you must eavesdrop in the masters’ common-room. It is no use studying the timetable.

If we stick to Hume’s method, far from getting what he hoped (namely, the conclusion that all miracles are infinitely improbable) we get a complete deadlock. The only kind of probability he allows holds exclusively within the frame of uniformity. When uniformity is itself in question (and it is in question the moment we ask whether miracles occur) this kind of probability is suspended. And Hume knows no other. By his method, therefore, we cannot say that uniformity is either probable or improbable; and equally we cannot say that miracles are either probable or improbable. We have impounded both uniformity and miracles in a sort of limbo where probability and improbability can never come. This result is equally disastrous for the scientist and the theologian; but along Hume’s lines there is nothing whatever to be done about it.”

Upon reading more closely, my second impression was wrong, and this passage is a total mess.

First, probabilities of all kinds hold inside a framework of assumed uniformity of nature, not just Hume’s. As Hume and others explain, we need a degree of background uniformity to observe change and identify causality. What’s more, to infer that observed causality and change into the future (i.e. to formulate a probability), we need to assume the laws of nature are uniform, that the world will operate the same in the future as it does the past. This is true of any formulation of probability. Think of one that doesn’t, I’ll wait.

Second, I don’t think it’s true that “No study of probabilities inside a given frame can ever tell us how probable it is that the frame itself can be violated.” Models (“frames”) of probability have margins of error and bands of uncertainty. Typically, when statisticians say that their model is 80% certain of an outcome, 20% of the time it will be wrong. Hume’s formulation is similar, but in the case of probabilities of laws of natures, they have not been observed to act otherwise. Lewis quickly transitions into a vague illustration about Jones getting in trouble, and he doesn’t elaborate on this point or the illustration. This comes off as very shifty, as not only is the factual claim wrong, but the metaphor is ambiguous as well (and I honestly don’t have the time and patience to decode it, especially if Lewis is too lazy to do so himself).

Third, the second paragraph really can’t make sense unless you completely rewrite Hume’s argument to be about definitions, confuse laws of nature with uniformity, or understand natural laws to be unbreakable edicts and not well-supported observations.

Contra Lewis, when a novel phenomena happens, lowering our confidence in a natural law, uniformity of nature is not questioned, but the law of nature itself. As the uniformity of nature is not questioned, Hume’s “kind of probability” is not suspended.

Finally, reading between the lines, it seems that Lewis is complaining that there is no metaphysics or ontology in Hume’s analysis, that probabilities are formulated by what is observed and calculated, free of influence of what is metaphysically or ontologically possible.

For Hume, this is a feature, not a bug. It’s trivially true that someone who believes miracles or a religion are possible can rationally believe a miracle is possible. What Hume is interested in is whether someone who has no prior religious commitments should believe in them, making as few metaphysical or ontological assumptions as possible. One of those assumptions happens to be the uniformity of nature, others are his formulation of probability.

I can understand why this is frustrating to miracle and religious believers (I may write about this topic in a future post). But the way you prove that a wise person with minimal metaphysical or ontological assumptions and no prior religious commitments can rationally believe in a religious miracle is to make the argument without appealing to religious commitments or metaphysical or ontological assumptions. To this day, I don’t think it’s been done.

The Audacity!

Okay, now it’s time for some meanness (it’s okay, C.S. Lewis is not alive and if he’s correct about miracles and God, he’s probably in heaven and so I won’t hurt his feelings).

Let us for the moment cease to ask what right we have to believe in the Uniformity of Nature and ask why in fact men do believe in it. I think the belief has three causes, two of which are irrational. In the first place we are creatures of habit. We expect new situations to resemble old ones. It is a tendency which we share with animals; one can see it working, often to very comic results, in our dogs and cats. In the second place, when we plan our actions, we have to leave out of account the theoretical possibility that Nature might not behave as usual tomorrow, because we can do nothing about it. It is not worth bothering about because no action can be taken to meet it. And what we habitually put out of our minds we soon forget. The picture of uniformity thus comes to dominate our minds without rival and we believe it. Both these causes are irrational and would be just as effective in building up a false belief as in building up a true one.

This fucking guy! The stones on this man! To say Hume is wrong about the uniformity of nature and then to speculate why we assume the uniformity of nature…by giving the same reasoning Hume did almost 200 years prior! And to not at least credit Hume! The audacity!

The placement of this passage (after criticizing Hume’s argument) suggests that, at best, Lewis knew it was Hume’s reasoning, but for some reason, he didn’t believe his readers needed to know that (Did I say that was good? That’s actually bad!). Or worse, he truly didn’t know this was Hume’s reasoning and believed that he was saying something novel.

Considering Lewis was a nice, wise guy, and it’s standard procedure to cite arguments that aren’t yours, or to acknowledge when someone you’re criticizing makes a good point, I’m inclined to think Lewis has no idea that this is a Humean argument. And for that reason, I have a hard time thinking Lewis has even an intermediate understanding of Hume.

Why I View C.S. Lewis Somewhat Negatively Now

I’ll admit that this post probably came off as polemical or nitpicking, but to understand why I’m taking Lewis down a peg, we have to look at the overall influence on how we talk about miracles, decades later. Lewis got Hume wrong in ways that professional philosophers likely understand, but that Christians and apologists do not.

Lewis erroneously asserted that Hume was inconsistent and more skeptical than he actually was. He misunderstood basic facts about Hume and his arguments, by confusing laws of nature with the principle of the uniformity of nature. He made some bizarre claims about Hume’s formulation of probability that’s actually true of all probability. And he also said downright false things about probability models.

Now, we all make mistakes, and sometimes we write posts and articles that are bad or wrong. But C.S. Lewis was a famous Christian apologist who wrote these arguments in a book, and has been praised for it for decades. If one can fall up as a philosopher, this is how.

Today, I would wager more people have read C.S. Lewis than David Hume in the Christian West. As a result, I think more people misunderstand Hume’s argument than understand it, while also having the smug arrogance towards anyone who shoots down that arrogance.⁶

Put more bluntly, when you do bad philosophy and you’re famous,⁷ you have a duty to do the scholarship correctly. If you don’t, it’s likely you’ll mislead generations of people. I think Lewis did that with Hume, and that’s why I am polemical towards Lewis and anyone who mindlessly repeats his criticisms. If you make a mistake this bad and misinform as many people as Lewis did, you deserve some harsh words.

Narnia is one of my favorite fantasy series though!

1. The “circularity” or “definition” rebuttal relies on the idea that Hume is making an a priori argument. In reality, Hume’s argument is a posteriori, and we can infer that due to textual clues and a general understanding of the nature of Hume’s argumentation on many issues. What’s more, when you examine the structure of Hume’s argument, it’s clear that its foundation is matters of fact which can be demonstrated false.

2. You can find a free PDF of this book freely on the internet (I found it in one google search), but there’s also a post by Parker’s Ponderings that summarizes it well. I will be using the PDF for this post. Weirdly enough, there may be some formatting errors from the PDFs, I have no idea how to explain that.

3. Or any religious person investigating an alternative religious tradition and finding it lacking

4. It’s important to note that Hume doesn’t believe miracle testimony ever amounts to a probability, but that’s another post.

5. I can hear some people objecting that questioning fundamental assumptions is what philosophy is all about. That’s true! But there’s a difference between being skeptical toward a claim or argument because a premise is false or the logic is bad, and doing so because someone raised a specious objection that had nothing to do with either a claim’s logic or factuality. For Hume, humoring someone trying to doubt the laws of nature with miracle testimony is a similarly specious objection.

6. Speaking from Experience!

7. It’s perhaps worse if you’re famous and religious!