Peter J. Leithart on Media & the Nature of Science
If there were conclusive, undeniable proof for Darwinism, one would have expected Public Television’s week-long special, Evolution, to allude to it. It didn’t. Instead, the program contented itself with providing often-fascinating evidence of comparatively minor variations, and let computer graphics fill in the gaps left by the evidence. Scientists were shown explaining how they could manipulate genes to create fruit flies with legs coming out of their heads, how they could combine the genetic material of insects and mice, and how natural selection enables viruses to combat the drugs designed to kill them. Meanwhile, the graphics showed fish sprouting legs and turning into salamanders, small rodents morphing into giraffes and tigers, ape-men wandering the plains.
As presented by the program, the argument for evolution turns largely on an equivocation on the word species. When the word is defined technically as a group of living things that share certain characteristics, especially an inability to interbreed with members of other groups, it is true that new species do develop. Plants have been crossed to produce offspring that cannot be crossed with their parents.
But that is a far cry from providing evidence of the sort that Darwinism needs to succeed. As a theory about the origin and development of all species, it must not only provide evidence of the development of “new species” in the narrow technical sense, but of the development of new families and genuses. Not a scrap of evidence for change of this magnitude was presented on the program.
A Yawning Hole
Given this yawning hole in the argument, something other than evidence must account for the widespread confidence about Darwinism among scientists. Darwin speculated that the accumulation of small changes over a long period of time might produce the major changes required for the present diversity of species, though neither he nor his successors could produce any evidence that it did. The problem is not the speculation per se; every great theory, scientific or otherwise, includes some element of speculation.
Once one recognizes that Darwinism rests on a speculation, and that that speculation has not been demonstrated by science, it becomes clear that the speculation that God created living things in groups that develop and evolve within fairly strict limits is no more speculative than Darwinism. Why then is the Darwinian speculation so widely held to be preferable to creationist speculation? Even if life did evolve over unimaginable eons, why would scientists prefer a naturalistic account of this evolution to theistic evolution? Why, in short, do scientists prefer Darwin to Moses?
One of the main reasons has to do with the operating definition of science. In a web discussion of the program sponsored by Idaho Public Television, for which I served as co-moderator, I asked the other moderator, an evolutionary biologist from Idaho State University, to explain what qualifies as science. She answered by citing Judge William Overton’s well-known definition from a 1981 Arkansas education case (helpfully reminding me that Overton’s decision was the “law of the land,” as if dissent might be not only unscientific but also illegal).
Overton listed five characteristics of scientific study: “(1) It is guided by natural law; (2) It has to be explanatory by reference to natural law; (3) It is testable against the empirical world; (4) Its conclusions are tentative—that is, not necessarily the final word; and (5) It is falsifiable.” As Phillip Johnson has pointed out, the possibility of science accepting the Creation is ruled out by definition, because God’s actions are not explainable by reference to natural law.
“Law of the land” though it is, Overton’s formulation—which is the common definition among scientists—is ultimately incoherent. He did not provide any clues about what he meant by the “nature” behind the natural law, and that ambiguity is fatal. “Nature” may mean all reality or it may mean one aspect of reality, which may or may not interact with a supernatural aspect. But in none of these cases can the definition be sustained.
Suppose that “nature” means “all reality.” Nature is all that is, was, and ever shall be, world without end. It follows that everything is in principle subject to scientific investigation, every theory about reality is testable and falsifiable, every phenomenon is potentially explainable in terms of natural law, even if science has not yet explained it. But this begs the obvious question: Is such a definition of science scientific? What is the argument for the assumption that every natural phenomenon is explainable in terms of natural law? Is there a scientific (i.e., empirically testable and falsifiable) argument for that claim?
If not, and it is hard to see how there could be such an argument, the whole of science appears to be built on an assumption of a distinctly unscientific sort. There is no problem with that, so long as scientists are willing to admit that they are starting from presuppositions. (And are willing to grant that other scientists may start from different presuppositions.) Conceding this, however, would mean abandoning the common definition of science, since it would be an admission that some theories—the theory that nature is all there is, for instance—are beyond scientific investigation. If “nature” means “everything,” the common definition of science is self-refuting.
But suppose “nature” refers only to one aspect or segment of reality. Perhaps this means that we live in a bifurcated universe, which includes both natural phenomena comprehensively explainable in terms of natural law and a supernatural realm beyond the reach of science. There is a realm of science, and a realm of not-science; a realm of nature, and a realm of not-nature.
But this raises the essential question about the relation of nature to not-nature. There are two possibilities: Either the two realms are wholly distinct and never interact, or they do interact. In both cases the common definition of science refutes itself.
On the one hand, we might live in a bifurcated universe in which the supernatural realm never interacts with the natural. There may be a God, there may be angels, there may even be fairy godmothers, but they are polite enough to refrain from nosing and poking around in our business. But on what basis could one conclude that the two realms, if they exist, are completely separate from each other? Is that a scientific conclusion? It cannot be; how does one construct an experiment that will survey the boundaries between nature and not-nature?
In response to Kant’s idea of a “boundary” between the world of appearances (what he called the phenomenal) and the world beyond the reach of the senses (what he called the noumenal), Wittgenstein observed that we know there is a boundary only if we can see past the boundary. If we can see past the boundary of nature, however, we can observe the supernatural territory on the far side, and if we can observe it, it can be investigated by science. If it can be investigated by science, it is part of the natural world.
Thus a bifurcated universe of nature/supernature collapses into a purely natural universe. In the end, this definition of nature as divided between nature and supernature looks suspiciously like a metaphysical presupposition, and we are back to the conclusion that science is grounded on assumptions that cannot be proved scientifically.
On the other hand, we might live in a bifurcated universe in which the supernatural realm does interact with the natural. Tinkerbell might appear, the exorcist might legitimately be called in when the patient’s head starts spinning like a top, and one might encounter the incarnate God in a Galilean pub. By the common definition of science, that, too, is a metaphysical rather than a scientific view of reality.
If this is how “nature” is construed, however, scientists cannot be certain that every natural phenomenon has a natural law explanation. It is possible that something in the supernatural realm has produced an effect in the natural realm. And if the natural and supernatural interact, then those who believe that nature points to a creator are still doing science when they appeal to God as the cause of the universe. If the Creator can be called in as an explanation of creation, the limitation of science to natural explanations has to be abandoned. Hold on to this idea of nature, and you have to let go of the common definition of science; hold on to the definition of science, and you have to give up this idea of nature. You can’t hold on to both at once.
PBS’s Public Service
Despite its glaring inadequacies, PBS has done a public service by airing the program. Above all, it has demonstrated the need for a widespread rethinking of widespread concepts of nature and the nature of science. By the reigning definition, science limits itself to natural phenomena, but science has erected the fence between nature and not-nature unscientifically—it is an assumption science invests with all the authority of scientific objectivity and certainty. Worse, many scientists go about their business like ranchers convinced that there is nothing on the far side of the fence line, or that, if there is, it will surely leave the herd alone. Refusal to consider what’s beyond the fence makes for unsuccessful ranching, and it makes for muddled science.
Beyond that, Evolution has provided further evidence of the metaphysical character of Darwinism, has made the vacuity of the broad claims of evolution plain to a large audience, and has demonstrated that, as a theory about the origin of species, evolution has little going for it beyond massive public funding, most of the prestige university posts, and, especially, “way-cool” computer graphics.
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