Some years ago, a creationist challenged me, “Burt, how would you go about disproving evolution? It’s non-falsifiable and, by definition, cannot be science.”
Challenged me it did - I was unable to think of a good answer. At least, I was unable until I consulted with the brainiacs in Kansas Citizens for Science. The answer, like just about any answer when considering involving evolution, is to look at the past and examine evolution when it was back fighting for its life.
We’ll discuss this limited aspect of the history of evolution, along with why it’s important, on flip side…
When Darwin first published his noodlings on natural selection, he made very specific claims about the time courses involved. (Unlike a recently litigated alternative perspective occasionally mentioned in these forums.) Specifically, his theory required millions or billions of years, not thousands of years, to work.
This is remarkable because scientists of the time were not aware of the nuclear reactions like fusion. It’s pretty common knowledge that fission bombs (like the ones dropped on Japan) put out a lot more energy than chemical bombs (like the ones dropped on Germany), and fusion reactions potentially release even more energy than fission reactions. In order to understand one reason why Darwin’s hypothesis was fighting for its intellectual life, you have to imagine yourself in a world where fission and fusion were as yet undiscovered.
The sun puts out a lot of energy. A heck of a lot. Physicists of Darwin’s day could calculate the energy expenditure over time that the sun was releasing and knew the volume that the sun was occupying. Even if they used the most exothermic and energy releasing chemical reactions (say, our modern equivalent of the high explosives looted by the Iraqis from our depot during our invasion, HMX), they still were left with the conclusion that the sun would be using up its fuel at an alarmingly high rate. (In all fairness, they didn’t think the sun was burning chemically even as early as Darwin’s time. More for those interested here.)
What happened, obviously, was that Darwin put forward a theory that presciently predicted the large time scales understood to be required for our solar system’s development and life’s evolution. (Or, rather, put his chip down on the hypothesis of geologist Charles Lyell, who proposed millions or biliions of years and was Darwin’s contemporary.)
In the fullness of time, fusion reactions were discovered, allowing the sun to release large amounts of energy and yet be billions of years old. Darwin’s theory has since assimilated Mendelian and modern understandings of genetics, genetic drift, stabilizing selection, and a host of other advances since he last revised Origins (which is why “Darwinism” properly should refer only to the understandings of evolution as Darwin knew them). And rather than being dismantled by all the new findings, those new findings have been subsumed into evolution.
What results is a model of change for biology - a theory, as scientists define the term - that has been so amazingly successful at explaining and predicting observations in the natural world that creationists are now arguing that it can’t be science because it is so amazingly predictive and useful. In this vein, the creationist challenger to me from years ago and Reverend Creech writing in Agape Press, come to mind.
L. Harrison Matthews in the forward of a 1971 edition of Darwin’s Origin of Species, once concluded: “Our theory of evolution has become … one which cannot be refuted by any possible observations. It is thus ‘outside of empirical science,’ but not necessarily false. No one can think of ways to test it.”
There can essentially only be one reason for favoring evolution, and that reason has nothing to do with science. It has to do with something outstanding British biologist D.M.S. Watson said in Nature back in 1929: “[T]he theory of evolution itself, a theory universally accepted not because it can be proved logically coherent evidence to be true but because the only alternative, special creation, is clearly incredible.”
Keep this in mind the next time someone challenges you saying that evolution cannot be disproven. Point out to your challenger that, like any successful theory, if you trace it back to when it was first an idea battling its way to the top, it was indeed fighting for its life. Also point out to your challenger that we scientists have a history of awarding revolutionary ideas (and their discoverers) with success and prestige, provided the ideas in question turn out to be more useful than the ones currently used. You should therefore encourage your creationist challengers to either let scientists do their work, or join them in doing it.