The Fact and Theory of Evolution
You don’t need to be a scientist to know that there’s a big difference between physics and biology. But you probably do need to be a scientist to be familiar with a subtle, but critical distinction between these two disciplines.
Physicists are very quick to challenge the central theories and assumptions of modern physics. Biologists, however, are unwilling to do the same.
As Jeff Zweerink described yesterday in his TNRTB entry, physicists recently tested one of the fundamental assumptions of general relativity, the Lorentz Invariance principle. Even though general relativity is considered by many to be one of the best-established principles in all of science, physicists seem to delight in any opportunity to prove it wrong.
This situation stands in sharp contrast to the way that evolutionary biologists interact with the theory of evolution. They steadfastly refuse to even entertain the possibility that this paradigm for life’s origin and history might somehow be unfounded.
Evolutionary biologists, in order to avoid any critical evaluation of the validity of biological evolution, hide behind the statement attributed to the famous geneticist Theodosius Dobzhansky that
Nothing in biology makes sense except in the light of evolution.
Yet, one could maintain that nothing in physics makes sense except in light of general relativity (and quantum mechanics). Somehow this doesn’t prevent physicists from ruthlessly pursuing ways to falsify one of the cornerstone ideas in their discipline.
Evolutionary biologists, most certainly, would protest any characterization that intimates at their reluctance to test biological evolution. They maintain that the theory of evolution is subjected to ongoing, critical evaluation.
Evolution is both a Theory and a Fact
In his book, The Triumph of Evolution and the Failure of Creationism paleontologist Niles Eldredge represents most evolutionary biologists when he states that
The common expression ‘evolutionary theory’ actually refers to two rather different sets of ideas: (1) the notion that absolutely all organisms living on the face of the Earth right now are descended from a single common ancestor, and (2) ideas of how the evolutionary process works - Creationists love to gloss over this rather clear-cut, simple distinction between the idea that (1) life has evolved, and the sets of ideas on (2) how the evolutionary process actually works. (page 24)
In other words, Eldredge and other evolutionary biologists maintain that evolution is both a fact and a theory. That it occurred is the fact. How it occurred is the theory. Biologists actively debate and critically assess evolution’s mechanism, but they insist this debate shouldn’t be interpreted to indicate that the fact of evolution is on uncertain footing. They see no reason to test that evolution occurred.
Generally, evolutionary biologists point to two main lines of evidence to support evolution’s status as fact. The first is the shared anatomical features possessed by organisms. Biologists use these common characteristics to group organisms into nested clusters or hierarchies. Evolutionists take this pattern to indicate that life descended with modification from a common ancestor. In other words, they take this to indicate that life evolved. The second line of evidence is the fossil record, which shows that different life-forms existed on Earth at different times in its history and reveals a progression from simple to complex organisms.
But does this evidence necessarily compel evolution? It is a far cry from the quantitative certainty that physicists have about general relativity.
The nested clusters could easily reflect the handiwork of a Creator who chose to employ a common blueprint and reuse many of the same design elements. Accordingly, evolution’s common ancestor is replaced by an archetype that exists in God’s mind. As for the fossil record, again this finds ready explanation. As indicated in the Genesis 1 and Psalm 104 creation accounts, the Creator transformed the planet and brought life into existence in a purposefully progressive fashion. This progression includes the creation of different life-forms at different eras in Earth’s history. Hence, the fossil record’s features find explanation.
If other models can logically account for the data from the fossil record and the patterns observed among living organisms, then why does a segment of the scientific community view that evolution occurred as fact and not a theory? Philip Johnson, one of the founders of the Intelligent Design Movement, argues that the contemporary scientific enterprise is inextricably intertwined with the philosophical position called naturalism. According to this system of thought, reality exclusively consists of the physical, material universe. Nothing exists beyond the universe. In other words, naturalism rejects the possibility of the supernatural and miracles. This means that science in the naturalistic framework must explain the universe and all phenomena within it exclusively through natural-process cause and effect.
If science is cast within the naturalistic paradigm, then the fossil record, which shows different life forms at different eras and a progression of organisms from simple to complex, must mean that life transformed from one form into another through natural means alone. It means that evolution is a fact. The philosophical assumptions of contemporary science force the fact of evolution, not the evidence at hand, necessarily. Natural process evolution must be a fact, since the philosophy of naturalism, by definition, will not allow supernatural explanations. No other choices are philosophically permitted. Evolution is a fact only if naturalism is embraced.
Other philosophical and theological positions allow for the fact of evolution, but also keep open the possibility that supernatural explanations may account for features of life and aspects of its natural history. For biologists to establish evolution as a fact within this broader context, the theory must withstand the rigors of scientific testing. Within a framework that allows for supernatural causation, that evolution occurred, like all scientific ideas, is provisional and must be constantly evaluated with each new discovery and in juxtaposition to alternative theories.
An approach to science that leaves open the possible involvement of a Creator aligns much more closely to the exemplary practice of physicists in their unending quest to falsify general relativity. A theistic paradigm applied to science spawns an intellectual milieu that allows both the fact and the theory of evolution to be analytically gauged.