Some comments on Hume and miracles

Comment threads are easier to resurrect than corpses

In his re-post of February 26, 2024 (What is Hume Doing In His Essay “Of Miracles”?), John W. Loftus asks:

So let me put it to my readers. What would it take for you to believe a miracle had taken place given natural law and the fact you have never previously experienced a miracle nor anyone else you know (that is true, right?) What kind of miracle would it have to be? Let’s say one day a man’s arm was blown off and the next day it had regrown. It’s never going to happen, that’s for sure. If someone claimed it did, would you believe it was a magic trick of some kind? How about a virgin having a baby without any male sperm? How about someone telling you s/he heard god’s voice? What about YOUR hearing a god’s voice? What of someone coming back to life after being embalmed at the morgue?

The original article appeared several years ago; apparently as a result of that, the comments below the re-post article are closed. So that we may Lift Every Voice and … comment, I’m posting a reply article, which will have the welcome side effect of starting a new discussion thread.

Note that this business of miracles has been beaten to death in many books, articles, and blog posts, so it would be a miracle if anything I write is either original, comprehensive, final, or perhaps even correct. But maybe something here will be useful to someone. Just because everything’s in libraries doesn’t mean we all know all of it. And as always if you spot a goof, correct me.

The arrow of time - one of the ways to distinguish the mundane from the miraculous

Reality is kind of a One Direction concert

So, what would it take for me to believe a miracle had taken place? Two of John’s hypotheticals involve something like reversals of the arrow of time. There are many natural processes which we only ever observe moving in one direction. If you were to record such a one-way process as a motion picture, you could replay the event forwards or backwards. The backwards replay would then appear jarringly unnatural. For example, imagine someone’s arm exploding, and then un-exploding. Things sometimes explode, but they do not then un-explode. Similarly, we could record a person dying and then being embalmed by an undertaker, but we never observe that process reversing itself: a person being un-embalmed and then resurrected. Cremating the corpse would make for an even more dramatically impossible backwards replay, as that would require the widely scattered combustion products to coalesce back and un-combust themselves to reconstitute the corpse, which would then re-animate. (As an aside, the cryonics movement rests on the premise that super-duper technology of the future will be able to re-animate frozen corpses and repair whatever diseases or accidents killed them. If you’re skeptical about that you’ve got lots of company.)

Similarly, we can videorecord a baker making bread. The backwards replay would show the loaf of bread un-baking back into dough and the dough un-mixing back into the original ingredients. If we ran it farther back, we’d see the flour traveling back to the store, and then to the mill, and un-milling itself back into wheat, which would then un-grow back into carbon dioxide, water, soil nutrients, and the wheat seeds.

The arrow of time happens to be a paradox. According to the Wikipedia article:

The arrow of time paradox was originally recognized in the 1800s for gases (and other substances) as a discrepancy between microscopic and macroscopic description of thermodynamics / statistical Physics: at the microscopic level physical processes are believed to be either entirely or mostly time-symmetric: if the direction of time were to reverse, the theoretical statements that describe them would remain true. Yet at the macroscopic level it often appears that this is not the case: there is an obvious direction (or flow) of time.

Entropy as an arrow of time

Shot through the heart, and Clausius is to blame; he gave the heat death of the universe a bad name

We can think of entropy as an arrow of time. One way to think about this is in terms of probability: everything that happens is an “attempt” by the universe to push itself into a more probable (or more disordered) state. Local excursions into lower probability (higher order, lower entropy) are possible, but they must be somehow coupled to larger offsetting increases in entropy elsewhere. A classic example is the evolution of life on Earth, which represents a substantial increase in order. It was driven mostly by the much larger decrease in order in the Sun as it consumed its nuclear fuel, unleashing solar energy which was then harnessed by the mechanisms of mutation and natural section. This decrease in order manifested largely as nuclei in the Sun transmuting along the curve of binding energy. The evolution of life also depended on plate tectonics which is driven largely by the decay of heavy radionuclides inside the Earth, as they approach the same spot on that curve of binding energy from the upper end. Those heavy radionuclides in turn originated in earlier supernovae and neutron star mergers.

(And sorry if I upset fans of Rudolf Clausius and/or Bon Jovi and/or the English language with my terrible puns. Sticklers might protest that Lord Kelvin is more to blame for the heat death of the universe.)

The second law: why anything happens at all

In the Preface to his book The Laws of Thermodynamics: A Very Short Introduction, Peter Atkins introduces the four laws of thermodynamics (emphasis mine):

The mighty handful consists of four laws, with the numbering starting inconveniently at zero and ending at three. The first two laws (the ‘zeroth’ and the ‘first’) introduce two familiar but nevertheless enigmatic properties, the temperature and the energy. The third of the four (the ‘second law’) introduces what many take to be an even more elusive property, the entropy, but which I hope to show is easier to comprehend than the seemingly more familiar properties of temperature and energy. The second law is one of the all-time great laws of science, for it illuminates why anything — anything from the cooling of hot matter to the formulation of a thought — happens at all. The fourth of the laws (the ‘third law’) has a more technical role, but rounds out the structure of the subject and both enables and foils its applications. Although the third law establishes a barrier that prevents us from reaching the absolute zero of temperature, of becoming absolutely cold, we shall see that there is a bizarre and attainable mirror world that lies below zero.

Given that the second law is why anything happens at all (as Atkins puts it), demonstrable violations of the second law might be strong candidates for miracles. No such violation has ever been reliably observed in the roughly 400 years of modern science. (The period of modern science is my focus because that’s when scientists have had an exponentially increasing capacity to detect, recognize, and record such violations of natural law, if any were to occur.) That’s how natural “laws” get to be called laws: they appear to be exceptionless. Thousands of scientists make millions of observations and nobody can demonstrate the “law” to admit exceptions. Then the engineers and industrialists join the party by stamping out millions or billions of artifacts made possible by the laws, and all of them appear to obey the laws as well. Then there is evolution, which mindlessly solved some molecular problems over a billion years ago, and the resulting genes and proteins have been “conserved” from yeast to humans. That means that at no point were the laws ever violated by enough to erase the adaptive advantages of those genes and proteins, which would have interrupted the Tree of Life. The laws of physics and chemistry that dictate the behavior of biomolecules have held sufficiently well since at least back to the last universal common ancestor.

Would you believe a miracle if you saw it?

Nobody has ever reliably demonstrated a violation of the second law, but suppose someone did. That leads to John’s thought question:

If someone claimed [that an exploded arm unexploded or grew back], would you believe it was a magic trick of some kind?

Skepticism would be my starting hypothesis. I’m aware of the history of failed attempts to violate the second law, such as with perpetual motion machines, water-fueled cars, and so on. As Hume famously pointed out in his essay Of Miracles, violations of natural law appear to be so improbable that almost any alternative explanation for our observation of a supposed miracle which does not violate natural law is more likely to be true.

I would certainly need more than someone’s claim! I would need evidence comparable in strength to the evidence that World War II happened.

We are smarter than me

I certainly wouldn’t set myself up as the final authority on what I’m seeing. For example, I’ve seen videos of close-up magic by David Blaine and others. Some of what they do looks to me like miracles, but I know they are just doing tricks that obey natural laws and fool my perceptions. Rather, I would rely on the entire community of scientists, magicians, skeptics, journalists, and so on to vet a miracle claim for me. For example, the Randi prize went unclaimed for over 50 years. If anyone had claimed it, I wouldn’t have needed to examine the claim for myself, given that the winner would probably have become a household name and probably would have started a whole new field of inquiry, with practical spin-offs galore. A real-life Hogwarts School of Witchcraft and Wizardry would likely spring up in no time around the trick - if it were reproducible. But as Richard Carrier and others have pointed out, if a “supernatural” phenomenon turned out to be reproducible, then it would satisfy one of the necessary conditions to be a natural phenomenon, and the result might be that it would get incorporated into the rest of science. (Reproducibility is among the foundations of the scientific method.) In the past, seemingly magical phenomena like electricity, magnetism, and radioactivity were eventually shown to be reproducible, whereupon they became part of science.

Do miracles have to be one-offs?

For a miracle to remain a miracle then, it might have to be irreproducible, and that creates all sorts of problems. One of the strongest forms of evidence for the plausibility of a phenomenon is being able to observe it or elicit it again under known conditions. If a miracle is a one-off, then we would lose the strongest argument for its plausibility. We might be left wondering if it were just some sort of a glitch, with no clear way to resolve that. We would only have the reliability of the records of that one event - and that reliability tends to decay over time, as memories fade, the original witnesses die off and can no longer be cross-examined, libraries full of documents get sacked and burned, physical books wear out, and so on.

Alleged reproducibility in the bible

Reproducibility of a sort sneaks into the bible. The books of the bible were written over a span of several centuries, and the times they purport to describe cover even more centuries. But throughout all that time, according to the bible, miracles were almost a dime a dozen. In all the bible stories involving people from Genesis to the Acts of the Apostles, it’s just one miracle after another. Reading the bible is not unlike reading the Harry Potter series with its spell-casting and wizardry and trampling of natural law underfoot. Perhaps it’s no coincidence that both of these domains of fiction enjoy such enduring popularity. Reality kind of sucks, since that pesky second law constantly works against us. Few people get everything they want just handed to them. Instead we have to work hard to temporarily and locally hold back the forces of decay. Everybody wants a shortcut, a magical way to “manifest” the goodies we want. The so-called “New Thought” law of attraction is the same kind of something-for-nothing snake oil that nearly every religion has always sold to the gullible.

Presupposing naturalism; the Moses and Red Sea example

John summarizes Levine (from The Cambridge Companion to Miracles):

Part I presupposes naturalism, Levine says. Philosophers like him, who rule out the possibility of miracles “are in effect presupposing or else arguing for a thoroughgoing naturalism. Hence, Hume’s empiricism commits him to naturalism, and if that goes unrecognized, his a priori argument in Part I of his essay against the possibility of justified belief in miracles is impossible to follow.” (p. 292). All one has to admit is that “naturalism is possibly false.” Once this is admitted “miracles are possible.” (p. 292).

John then quotes Levine directly (emphasis mine):

Hume is thus constrained by his empiricism in such a way that had he been on the shore of the Red Sea with Moses, and had the Red Sea crashed to a close the moment the last Israelite was safe, Hume would still be constrained by his principles to deny that what was witnessing was a miracle (p. 298).

There’s a tricky point about “principles” here - are we talking about principles, as in a prior commitment (an axiom, a presupposition, etc.), or are we talking about prior experience (an inductive conclusion)? See for example Richard Carrier’s Naturalism Is Not an Axiom of the Sciences but a Conclusion of Them and In defense of naturalism by Gregory W. Dawes. I confess to not having read enough of Hume or Levine to know whether Hume actually made the mistake that Levine appears to charge Hume with having made, but I don’t think that matters very much unless we’re trying to get past peer review, in which case we need all those attributional ducks in a row. Carrier and Dawes warn against this very mistake. Just read Carrier and Dawes and don’t make the same mistake yourself!

As to the Red Sea example given, I think Hume was in something like the same position with regard to most of what we now understand to constitute modern science. For example, during Hume’s life, nobody had a clue about plate tectonics (and thus why there are mountains, volcanoes, and even land above sea level at all); nor did anyone have a satisfying natural explanation for biodiversity; nor did anyone know how the stars shine (that had to wait for Hans Bethe in 1938); nor what a virus was; and on and on. Everywhere that Hume looked he saw candidate miracles, as far as anyone knew at the time. Given Hume’s lack of understanding of the physical mechanisms to explain the wonders he saw, his primary fall-back seems to have been regularity. For example, he didn’t know how the stars shine, but he saw that they always shine. Therefore, the shining stars didn’t constitute a miracle for Hume, even though a satisfying natural explanation lay centuries in the future.

Further, it’s worth recalling that the Moses and Red Sea example is a pure hypothetical, given that archaeologists and historians who aren’t Christian fundamentalists have accepted that the whole Exodus account is almost certainly fictional. See for example Did Moses Exist?: The Myth of the Israelite Lawgiver and The Bible Unearthed: Archaeology’s New Vision of Ancient Israel and the Origins of Its Sacred Texts. The Moses and Red Sea example is as likely to have actually happened as the successful spell-casting in Harry Potter.

Further reading

For more on the impossibility claims of science, see A Physicist’s Guide to Skepticism: Applying Laws of Physics to Faster-Than-Light Travel, Psychic Phenomena, Telepathy, Time Travel, UFOs, and Other Pseudoscientific Claims by Milton A. Rothman. If I were King of the World, I would require the people who reject the impossibility claims of science to live without the technological goodies made possible by science. That is, I would require the science deniers to live according to their professed beliefs. Among Christians, it seems that only the Amish minority comes close to such consistency of behavior with belief.

To understand the difference between “impossible” and the merely improbable, see The Improbability Principle: Why Coincidences, Miracles, and Rare Events Happen Every Day by David J. Hand.

For more on miracles, see (of course) the anthology John W. Loftus edited after his original blog post: The Case Against Miracles.

For more on Hume, see Hume’s oeuvre. If that’s too ambitious, start with Hume: A Very Short Introduction by A. J. Ayer, himself a prominent philosopher of the 20th century.

For the prior (and rather massive) blog activity and discussion history about these topics on Debunking Christianity, follow the labels.