Have you ever noticed theological or metaphysical premises built into some scientists’ arguments? This might be surprising given how often scientists argue that science and religion are entirely separate. Consider, for example, the arguments that have been made for homologies, which serve as one of the primary evidences for universal common descent in naturalistic evolution.
A homology, in biological terms, refers to a structural pattern that is common to different species and is thought to be the byproduct of evolution. The pentadactyl (i.e., five-digit) structure found in tetrapods (four-limbed vertebrates) is one example. It’s used by mammals, birds, reptiles, and amphibians alike, but for very different purposes (crawling, flying, climbing, digging, etc.). Evolutionists reason that since these various animal groups share this structure instead of having distinctive structures uniquely suited to their activities and environment, this is an indication of shared ancestry. Charles Darwin went so far as to say the existence of homologies would lead him to “without hesitation adopt [the theory of evolution], even if it were unsupported by other facts or arguments.”
But consider the metaphysical and theological arguments surrounding the evidence of homologies. Darwin says that the existence of similar structures among a variety of species is “inexplicable…on the ordinary view of creation,” and vestigial organs (a type of homology) present “a strange difficulty…on the ordinary doctrine of creation.” But, he argues, they can be readily explained by his theory of evolution. Why does he think homologies pose a problem for the creationist? His argument is that if God had created the different species, we should not find similar patterns among species.
Darwin held to the common view during his time that, as philosopher of biology Stephen Dilley puts it, “just as humans do not invent locomotive machines from a common type, but rather directly for specific purposes, so God created limbs at the species level de novo for specific environments, rather than modifying a more general type.” So, we would not expect to find common patterns, like the pentadactyl structure, in nature if God created the various species. Since we do find patterns like this repeatedly, God did not create them, or so the argument goes. And if God did not create them, then blind naturalistic forces did.
It becomes clear that this argument hinges upon a certain assumption about the way God would have created. Indeed, the utilitarian argument from design, which claims that every part of an organism has a function or purpose (which indicates it’s designed) had been employed by natural theologians like William Paley before Darwin began developing his theory, and Darwin, who had studied Paley’s work, attempted to falsify creationism with this understanding of creation in mind. Homologies were seen to contrast with this widespread notion of anatomical utilitarianism. So, in the words of biophysicist Cornelius Hunter, it appears “the proof of [Darwin’s] theory was the failure of divine creation.”
Evolutionists have used similar arguments in more recent times. Theodosius Dobzhansky, for example, claimed creation is false and evolution is true because God would not use common patterns throughout the various species. Rather, he expected that God would have used new traits and designs when creating different species. But notice once again that this is a theological argument.
Moreover, when we come across an “imperfect design,” philosopher of science Michael Ruse argues that it’s “good evidence that evolution has been at work…rather than a grand, directly intervening intelligence.” The assumption here is that God would not create such “imperfect” designs in nature. Yet Ruse’s argument here is a theological argument since it’s based on how he thinks God would have created.
Further, Stephen Jay Gould, who advocated the “nonoverlapping magisterial” approach to the relationship between science and religion (which holds that science and religion are separate spheres that don’t overlap) has used theological arguments to support evolution. He claimed, for example, that “Odd arrangements and funny solutions are the proof of evolution—paths that a sensible God would never tread but that a natural process, constrained by history, follows perforce.” Once again, this argument deals with Gould’s understanding of what creation should look like if God created it.
In this way, arguments for evolution are often intermingled with metaphysical and theological premises—even though scientists today often argue that religion has nothing to do with science. Evolutionists, from Darwin to today, have used “negative theology”—that is, “the failure to reconcile God and nature”—to support evolution. Keep in mind that these arguments aren’t scientific arguments but instead are metaphysical arguments since they’re based on one’s understanding of the nature of God and of creation.
Yet, it should be pointed out:
One could just as easily argue that the Creator used the patterns found in homologous structures so that scientists could more easily analyze his creations and figure out how biology works. On the other hand, one could argue that the imperfections of nature that the homologies reveal are a manifestation of the burden of sin upon the world. Such ideas are no more religious than evolution’s notion of a restricted god.