The Presocratic philosopher Empedocles was, by all accounts, an interesting character. Apparently¹, he asserted that he was a former god who had been reincarnated many times — including at least once as a fish — and claimed to be able to control weather and raise the dead. According to legend, he was so intent on convincing the populace of his divine status that he secretly hurled himself into the volcano Mount Etna (pictured above) to make it appear that he had ascended to godhood and vanished from the earth. His fraud was exposed, however, when — as fate would have it — the volcano hurled out one of his (extremely recognizable) bronze sandals. 

Well, “truth will out.” 

But this principle did not always work to poor Empedocles’ disadvantage. His claim to divinity may have been swiftly and volcanically debunked after his death, but another controversial claim of his was vindicated, albeit after a much longer waiting time — namely, his scientific hypothesis that light moves.

Aristotle Weighs In

Although that seems obvious to us now, the idea was met with considerable pushback at the time. Aristotle, for one, considered it absurd. He wrote:

Empedocles (and with him all others who used the same forms of expression) was wrong in speaking of light as “travelling” or being at a given moment between the earth and its envelope, its movement being unobservable by us; that view is contrary both to the clear evidence of argument and to the observed facts; if the distance traversed were short, the movement might have been unobservable, but where the distance is from extreme East to extreme West, the draught upon our powers of belief is too great.

Instead, Aristotle maintained that when light was produced it instantly spanned the available distance. 

Of course, Aristotle was wrong. As we all learned in school, light actually does move, at “lightspeed” (3.0×10⁸ m/s). But before you’re too hard on Aristotle, think of things from his perspective. The fact is, you can’t see light moving, no matter how hard you try. Light goes so fast that even later experiments, involving observations of the Moon or people standing on hills a mile apart, were unable to detect any delay in its transmission. Aristotle simply did not have the empirical tools to detect the movement of light, so what was the “father of science” to do but accept what evidence he had? 

And Aristotle’s name used to carry a lot of authority. (I mean, even more than it does now — in the Middle Ages, he was referred to simply as “the Philosopher.”) So for the next two millennia, proponents of a finite lightspeed had to fight an uphill battle against both the available empirical evidence and the authority of Aristotle. The “father of modern philosophy,” René Descartes. not only agreed with Aristotle’s view, but went so far as to assert that “it is so certain, that if one could prove it false, I am ready to confess I know nothing in all of philosophy.” 

A Strange and Unexpected Complication 

But little did Descartes know, a new invention — the telescope — was about to blow his position out of the water. Not long after Descartes death, a Danish astronomer named Ole Rømer was working as an assistant to the astronomer Gian Domenico Cassini at the Paris Observatory, measuring the orbits of Io, a moon of Jupiter. The purpose of the project was to devise a universal way of measuring time, which would allow navigators and cartographers to calculate longitude. In the process of attempting to compile accurate tables of the Jovian months, they encountered a strange and unexpected complication: the orbital period of Io seemed to consistently become shorter when the earth was moving towards Jupiter, and longer as the earth moved away. 

Now, why should Earth’s position change the orbital speed of a moon of Jupiter? Rømer realized that this must actually be due to the fact that the earth was moving towards and away from Jupiter so fast that its movement changed the amount of time it took the light from Jupiter’s moons to arrive at Earth.

Which meant that the speed of light was finite. 

Which meant that old Empedocles was right, and Aristotle and Descartes were both wrong.

That was the only answer that seemed to explain the observations. 

Even with this new evidence, not everyone was willing to acknowledge the non-instantaneous transmission of light so easily. Rømer’s own supervisor and collaborator, Cassini, never accepted his argument. But there was no going back. 

There’s a lesson here. We sometimes think of science as marching steadily forward after each brilliant insight, as each daring new hypothesis is proposed, then empirically tested, then rejected or accepted accordingly. But sometimes competing hypotheses can’t be empirically tested for a very, very long time. Sometimes, scientific progress on a question stalls until some other discovery affords us the opportunity to answer it — you can’t put a theory under a magnifying glass until you invent the magnifying glass. And in the meantime, the incorrect hypothesis may have become deeply ingrained as accepted fact. 

A Magnifying Glass for Darwinism 

A much more recent example of this kind of delayed progress concerns Darwin’s theory of evolution. 

As everyone knows, Darwin proposed that the complexity of life could be explained by an accumulation of tiny, beneficial variations over millions of years. But not all of his contemporaries found this theory convincing. Notably, the “irreducible complexity” argument now associated with Michael Behe was known in Darwin’s time. Some contemporary scientists questioned whether it would really be possible to build something complex, like an eye, in tiny incremental steps — wouldn’t you need to change several things at once to increase function in something with so many inter-reliant parts? 

But in Darwin’s view, you couldn’t definitively prove that any known organ actually was irreducibly complex. Who was to say that you couldn’t start with a simple, light sensitive spot, and then gradually accumulate helpful additions around it until you had a fully formed eye? Why not? 

He wasn’t wrong. It was easy enough to dismiss the irreducible complexity argument, because at that time no one knew what the most basic parts of a given biological system actually were. And that has only recently changed. Michael Behe was only able to write Darwin’s Black Box in 1996 because molecular biology had progressed to the point where you could exhaustively enumerate the parts of a biological system. And the method of “gene knockout,” which enabled scientists to test whether a molecular machine could function without a specific part, had only been discovered a few years earlier. 

As Behe explained in a talk following the publication of his book²: 

Darwin persuaded much of the world that a modern eye evolved gradually from a simpler structure, but he did not even try to explain where his starting point for the simple light-sensitive spot came from. On the contrary, Darwin dismissed the question of the eye’s ultimate origin: “How a nerve comes to be sensitive to light hardly concerns us more than how life itself originated.” 

He had an excellent reason for declining the question: it was completely beyond 19th-century science. How the eye works — that is, what happens when a photon of light first hits the retina — simply could not be answered at that time. As a matter of fact, no question about the underlying mechanisms of life could be answered. How did animal muscles cause movement? How did photosynthesis work? How was energy extracted from food? How did the body fight infection? No one knew. 

It took about two decades after the publication of Darwin’s Box Black for the idea that “Darwinism can’t explain everything” to become mainstream in the biology community. Now, it is common for evolutionary theorists to admit that a new theory of evolution is needed, or at least a new supplement to the theory. Peter Corning (Institute for the Study of Complex Systems) casually mentions that “Darwin’s theory does not provide an explanation for the rise of biological complexity…”. Andreas Wagner (University of Zurich) acknowledges that “[e]xperts still debate how Darwinian evolution can bring forth the truly new, because natural selection can select only what is already there.” Denis Noble (Oxford University) recently stated, “The fact is, I think neo-Darwinism is dead.” The five authors of the new technical work Evolution Evolving: The Developmental Origins of Adaptation and Biodiversity (Princeton University Press, 2024) write that leading evolutionary biologists are changing Theodosius Dobzhansky’s famous adage “Nothing in biology makes sense except in the light of evolution” to simply “Nothing in biology makes sense anymore.” 

It’s not that these scientists are jumping on the intelligent design bandwagon. Instead, they each have different theories about what the missing piece(s) in evolutionary theory might be — synergism, teleonomy, robustness and evolvability, Platonic structures… and so on. But what they all agree on is that something else is needed. That realization is the result of new technology allowing scientists to actually see the thing under discussion for what it is. 

A Magnifying Glass for Mechanism 

It doesn’t stop with Darwinism. Recent advances in molecular biology have also re-opened the age-old debate about what life even is.

Starting with Descartes, many philosophers and scientists have held that living organism are simply physical machines. That theory has always had a sort of empirical observation on its side: after all, we don’t see any non-physical element to living things. And we certainly do see a lot of mechanical complexity. So why invoke some spooky “soul” or “force” as a cause, when a type of cause that we can already observe might be enough to explain everything? 

That’s a fair enough stance to take — at least as a stand-in until you can test whether or not the cause you already observe really can explain everything. Once it becomes possible to test that, though, it would be better to go ahead and test it. 

Some contemporary scientists are trying to do just that. For example, evolutionary biologist Richard Sternberg and his colleagues are currently investigating whether it is mathematically possible for the physical structure of an organism to contain all the information needed to direct the development of that organism. On that, see the new book Plato’s Revenge: The New Science of the Immaterial Genome. In some “back of the envelope” calculations on the subject, physicist Brian Miller lists the different variables that may need to be accounted for by information from somewhere in order to account for a single cell: an estimated 10,000 gene states, 10,000 epigenetic states, 100 signaling molecule states, 100 extracellular and mechanical states, as well as variables having to do with cell size, shape, movement, and so on. After putting it all together, Miller concludes that the information requirements seem to be far greater than what could actually be stored in in that cell. 

It might be early to say whether these calculations are correct — but the point is, this kind of calculation is only just becoming possible. That’s why, until a few decades ago, it was easy to assert that everything in biology could be explained by physical mechanisms and algorithms: there was simply no accurate way to innumerate “everything in biology,” much less trace the origins of each variable. 

But now, we might be finally reaching a point where we can put the magnifying glass to the competing hypotheses of vitalism and mechanism. That also applies to the related debates about whether our apparent free will really is free, or if our choices are actually mechanistic. For example, an article in Nature published this April announced that, for the first time, neuroscientists had mapped a rat’s brain at the level of the individual neurons. This is the kind of detailed analysis we will need in order to finally prove whether something like “free will” is genuinely non-deterministic — and we’re only just now getting there.  

This is an exciting era, quite reminiscent of the 17th century. Like in the 17th century, questions that have long been considered settled — merely out of convenience, since there was no way to make progress on them — have now become quite unsettled. And we might soon know whether the established answers merit the status they have been given. 

There has been a long wait. But sooner or later, truth will out. 

Notes

1. If we take the first-person statements in his philosophical poems literally, as his ancient biographers did. 
2. “Evidence for Intelligent Design from Biochemistry,” lecture, Discovery Institute’s God and Culture Conference, Seattle, August 10, 1996. In Behe, Michael. A Mousetrap for Darwin: Michael J. Behe Answers His Critics. Discovery Institute Press, 2020.