We all know that the theory of evolution is as well-established as gravity, because we have been taught this in school all our lives. What many people may not know, however, is why evolution is as well-established as gravity.
In his 1888 book Evolution Joseph Le Conte, University of California professor of geology and natural history, and later president of the Geological Society of America, helps us understand why this is so. Of the fossil record, Le Conte writes:
[S]pecies seem to come in suddenly, with all their specific characters perfect, remain substantially unchanged as long as they last, and then die out and are replaced by others. Certainly this looks much like immutability of specific forms, and supernaturalism of specific origin.
According to a Nov 5, 1980 New York Times News Service article, the fossil record 100 years later still does not support Darwin’s belief that species must have evolved gradually: “The pattern that we were told to find for the last 120 years does not exist,” says Niles Eldridge, an American Museum of Natural History paleontologist. “There are very few examples—some say none—of one species shading gradually into another,” according to this report. “Darwin knew he was on shaky ground in extending natural selection to account for differences between major groups of organisms,” says the Times writer, but this does not suggest “weakness in the fact of evolution,” only in the “perceived mechanism.”
Le Conte next concedes that natural selection cannot create anything new:
… neither can it explain the first steps of advance toward usefulness. An organ must be already useful before natural selection can take hold of it to improve it.
Le Conte thus acknowledges the main problem with natural selection, which was called “the problem of novelties” in his day and today is known as the problem of “irreducible complexity.”
As I pointed out in a 2000 Mathematical Intelligencer article, the evolution of life actually looks much like the evolution of software, or any other human technology: there is a progression from simple to complex, but major new features consistently appear suddenly. “Gaps among known orders, classes and phyla are systematic and almost always large,” writes Harvard paleontologist George Gaylord Simpson. But if we thought about what gradual transitions between major groups of animals or major software versions would look like, we would understand why we do not see them: they would involve puzzling new, but not yet useful, features.
In another candid admission, Le Conte writes that while beauty in flowers can perhaps be explained by sexual selection, “The most gorgeous beauty is lavishly distributed even among the lowest animals, such as marine shells and polyps, where no such explanation is possible. The process by which such beauty is originated and intensified is wholly unknown to us.”
So why then is evolution as well-established as gravity? Le Conte explains:
We are confident that evolution is absolutely certain—not evolution as a special theory—Lamarckian, Darwinian, Spencerian…but evolution as a law of derivation of forms from previous forms…. In this sense it is not only certain, it is axiomatic… The origins of new phenomena are often obscure, even inexplicable, but we never think to doubt that they have a natural cause…
[T]he law of evolution is as certain as the law of gravitation. Nay, it is far more certain. The nexus between successive events in time (causation) is far more certain than the nexus between coexistent objects in space (gravitation). The former is a necessary truth, the latter is usually classed as a contingent truth.
Finally we understand. The law of gravity is a “contingent” truth: we believe it only as long as the evidence supports it. The theory of evolution is a “necessary” truth, it is not contingent on supporting evidence.
While Le Conte’s axiom that everything must have a natural explanation has certainly been a useful working hypothesis, it should be noted that since there is no chance of finding a “natural” explanation for the beginning of time, it would have forced scientists to reject the Big Bang theory before looking at the evidence. And it should also be pointed out that it requires us to believe (see the first chapter of my 2016 book Christianity for Doubters , which also includes a version of this post) that four fundamental, unintelligent, forces of physics alone could have rearranged the fundamental particles on our once-barren planet into computers, airplanes and Apple iPhones, and surely a reasonable person can be allowed to doubt this.
As useful as Le Conte’s axiom may be, shouldn’t we at least teach our school children that evolution is considered as well established as gravity by most scientists because of an axiom they accept, and not because the scientific evidence is overwhelming?