Toward a More Precise Definition of Evolution

Much confusion arises in the debate on Evolution and Creation because the opposing sides are working with different meanings of evolution. It would be helpful to refer to the taxonomy of evolution given by Stephen Myer & Mike Keas.

Principal Meanings of Evolution in Biology Textbooks:

1. Change over time; history of nature; any sequence of events in nature.
2. Changes in the frequencies of alleles in the gene pool of a population.
3. Limited common descent: the idea that particular groups of organisms
have descended from a common ancestor.
4. The mechanisms responsible for the change required to produce limited
descent with modification, chiefly natural selection acting on random
variations or mutations.
5. Universal common descent: the idea that all organisms have descended
from a single common ancestor.
6. “Blind watchmaker” thesis: the idea that all organisms have descended
from common ancestors solely through an unguided, unintelligent,
purposeless, material processes such as natural selection acting on ran-
dom variations or mutations; that the mechanisms of natural selection,
random variation and mutation, and perhaps other similarly naturalistic
mechanisms, are completely sufficient to account for the appearance of
design in living organisms.

In my view, there seems to be evidence to support Evolution (1-4). However, the evidence for general evolution/Evolution (5) remains inconclusive, if not debatable.

Myer and Keas suggest that Evolution (6) in reality is a metaphysical theory.

The “blind watchmaker” thesis, to appropriate Richard Dawkins’s clever term, stands for the Darwinian idea that all new living forms arose as the product of unguided, purposeless, material mechanisms, chiefly natural selection acting on random variation or mutation…Evolution in this sense implies that the Darwinian mechanism of natural selection acting on random variations (and other equally naturalistic processes) completely suffices to explain the origin of novel biological forms and the appearance of design in complex organisms. Although Darwinists and neo-Darwinists admit that living organisms appear designed for a purpose, they insist that such “design” is only apparent, not real, precisely because they also affirm the complete sufficiency of unintelligent natural mechanisms (that can mimic the activity of a designing intelligence) of morphogenesis. In Darwinism, the variation/selection mechanism functions as a kind of “designer substitute.” As Dawkins summarizes the blind watchmaker thesis: “Natural selection, the blind, unconscious, automatic process which Darwin discovered and which we now know is the explanation for the existence and apparently purposeful form of all life, has no purpose in mind. It has no mind and no mind’s eye.”

Myer and Keas conclude that Evolution (5) and (6) are expressions of reductionist and naturalistic worldviews with (ir)religious implications.

The blind watchmaker thesis suggests that the neo-Darwinian mechanism (and other related ones) functions as a designer substitute; it plays the role of creator in the scientific account of biological origins. Thus, clearly, this sixth meaning of evolution does have larger metaphysical or worldview implications.

Many philosophical naturalists or materialists find support for their worldview in neo-Darwinian theory for what seems to them good reasons. If neo-Darwinism is true, God’s creative activity (whether expressed discretely or gradually) would no longer be necessary to explain the origin of new living forms, since a strictly naturalistic mechanism would suffice…Further, if neo-Darwinism is true, then the natural world does not display evidence of actual design, divine or otherwise—as most religious theists affirm. For both of these reasons, neither neo-Darwinism nor other materialistic origins theories taught in the public schools (such as the chemical evolutionary theory of the origin of the first life) are religiously or metaphysically neutral.

Undoubtedly,  the biology textbooks give the impression that the theory of evolution is a settled scientific theory based on overwhelming evidence. However, evolution theory is a combination of empirical observations, logical inference, and tentative, disputed hypotheses.  Not surprisingly, a significant minority of scientists have doubts on Evolution (5),  many scientists have increasingly questioned the adequacy of the neo-Darwininan mechanism(refer to footnote 19 of their article for scientific authorities and peer-reviewed journals), and many more would dispute with the plausibility, if not scientific status of Evolution (6).

Scientific integrity should require the teaching of evolution in schools to acknowledge these ongoing scientific disputes. Evolution should be taught as a scientific theory that is open to critical scrutiny and not as a sacred dogma that cannot be questioned. Is it not the case that the historic mission of science has always been to demolish any sacred cow of human tradition with verifiable/falsifiable knowledge based on well-founded empirical evidence?

Reference: Stephen C. Meyer and Michael Newton Keas, “The Meanings of Evolution,”  Stephen C. Meyer and Michael Newton Keas,  in Darwin, Design, and Public Education, Rhetoric and Public Affairs, ed. John Angus Campbell and Stephen C. Meyer (East Lansing: Michigan State University Press, 2003), 135-56.

Note: This section was added as a post-script to an earlier post:

Relating the Bible to Science (Evolutionary Theory): Some Cautionary Notes LINK

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