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Theistic Evolution: A Reasonable Compromise?

by James S. Spiegel –

Almost a century and a half since the publication of Darwin’s The Origin of the Species, the issue of biological origins continues to be deeply divisive in Western culture.  This is no less true in the Christian church, which displays a broad spectrum of positions touted by persons both scholarly and religiously devout.  Christians who espouse creationism (the view that God specially made the various living organisms) are baffled that many of their fellow believers essentially agree with the Darwinian thesis.  They ask, “Doesn’t such a view fly in the face of Christian belief?”

 

Defining “Theistic Evolutionist”

 Those Christians (as well as Jews and Muslims) who affirm Darwinism are sometimes called “theistic evolutionists.”  Let’s define this term.  A theist is someone who believes in a God who is almighty, all-knowing, perfectly good, and who created the world and governs human history.  While there is much divergence of opinion among theists on numerous issues related to the doctrine of God, these are the bare bones of any theism deserving of that name.

Defining “evolution” is not quite so easy, as it is a rather ambiguous term.  For one thing, there is a distinction between microevolution and macroevolution.  Respectively, these terms are used to refer to change within species (hair color, body shape, etc.) as opposed to the emergence of entirely new species (e.g. the production of an organism that is reproductively bounded from its ancestors).  The former is a noncontroversial, directly observable level of evolutionary change.  Macroevolution, on the other hand, is the bolder and more theoretical claim made by Charles Darwin.  And it is typically intended by the general term “evolution,” such as when someone is described as a “theistic evolutionist.”  In what follows, I will use the term “evolution” to refer to the macroevolutionary thesis.

 

Why Be a Theistic Evolutionist?

Evolutionists claim that the different species of organisms were produced naturally, as opposed to being brought about through special creation or intelligent design.  Moreover, they make crucial claims regarding the mechanism that produced the species.  The mechanism of evolutionary change, of course, is natural selection.  Darwin’s profound observation was that those organisms that are best adapted to their environments are more likely to reach reproductive maturity and thus perpetuate their traits through their offspring.  So far, there is nothing controversial here.  But things get a bit dicey when the evolutionist goes on to make a further claim about the scope of explanatory power that the principle of natural selection affords us—namely that this principle accounts for the natural production of all organisms.  That is, on the standard evolutionary account, all living organisms have a common genealogical ancestry, having descended from some single living organism from ages past.  Or, on more modest accounts, every organism has descended from some single organism within its phylum.

But why would a theist opt for such a scheme?  Why appeal to natural causal mechanisms to explain what can just as easily be accounted for by appealing to special divine creation?  The answer, insist theistic evolutionists, lies in the nature of science.  Scientific accounts of phenomena are, by definition, natural, involving causal explanations in terms of physical entities and principles.  To appeal to supernatural causes, whether God, angels, or non-material human souls, breaks the rules of science, so to speak.  If science is analogous to a game, then the basic point of the game is to explain as much of the natural world as one can without transcending it causally.  By appealing to God as the source of speciation, creationists and intelligent design (ID) theorists essentially cop out of the “game” of science.

Thus, like atheistic evolutionists, theistic evolutionists are committed to explaining all natural phenomena in terms of other natural phenomena.  This procedural guideline is called methodological naturalism.  As opposed to philosophical naturalism, which affirms that in fact only the physical world exists, methodological naturalism is simply the practice of doing science as if only the physical world exists.  While ultimately committed to the reality of God as creator, sustainer, and redeemer of the world, the theistic evolutionist refrains from allowing these beliefs to intrude upon her scientific research and theorizing.

Ironically, many theistic evolutionists give theological grounds for their methodological naturalism.  Howard J. Van Till, for example, defends this approach by appealing to the concept of “functional integrity.”  This is the notion that God has made the world developmentally complete, so that from creation no new supernatural intervention has been necessary to achieve God’s creative purposes.  In other words, says Van Till, the world “suffers no gaps or deficiencies in its economy that need to be bridged either by words of magic or by the Creator’s direct manipulation.”[i]

Theistic evolutionists enjoy a distinct advantage over their atheistic colleagues.  The former have a reasonable explanation for the origin of life, whereas the latter do not.  Atheistic (and agnostic) evolutionists must affirm chemical evolution, the thesis that living cells first evolved from non-living matter.  The odds of such occurring are so remote as to be far beyond the realm of possibility.  For example, Frederick Hoyle and Chandra Wickramasinghe calculated the odds of a naturalistic evolutionary origin of life, assuming a 20-billion-year age of the universe, at approximately 1040,000 to 1.[ii]  So absurd is the chemical evolutionary model that some esteemed naturalists have even proposed as a more plausible alternative the theory that life was brought to Earth by alien beings.[iii]  The theistic evolutionist, on the other hand, need only appeal to the creative activity of God to explain life’s origins.  (Strangely, some theists, including Van Till, prefer not even to do this and thus inherit all of the problems plaguing chemical evolution.)

So the theistic evolutionist avoids one serious problem facing atheistic evolutionists.  But significant problems remain as we will see.

 

Problems with Theistic Evolution

First, there is the lack of fossil evidence for alleged transitional forms of organisms (e.g., between reptile and bird, reptile and mammal, land mammal and sea mammal, etc.).  Darwin himself lamented that this was a significant problem for his theory.  But the situation has only worsened over time for Darwinists when it comes to the fossil record.  David Raup, whom Steven Jay Gould once dubbed “the world’s most brilliant paleontologist,” describes the problem,

Most people assume that fossils provide a very important part of the general argument made in favor of Darwinian interpretations of the history of life. . . .  Well, we are now about 120 years after Darwin, and knowledge of the fossil record has been greatly expanded. . . .  Ironically, we have even fewer examples of evolutionary transition than we had in Darwin’s time.[iv]

Note that this is no mere nuisance for the Darwinist.  As a scientific paradigm, the reasonableness of the evolutionary thesis of common ancestry depends upon empirical data.  And the key domain for such data is paleontology, the study of fossils.  So the lack of sufficient fossil evidence to support the theory represents, to put it mildly, a major problem with the notion of common ancestry.

A further difficulty concerns the Darwinian paradigm’s dependence upon randomness and genetic mutations.  The great majority of mutations are not helpful, and any major beneficial structural change would typically require a convergence of numerous helpful mutations.  Nobel prizewinning biochemist Albert Szent-Gyorgyi illustrates with the following example:

“Herring gulls” have a red patch on their beak. This red patch has an important meaning, for the gull feeds its babies by going out fishing and swallowing the fish it has caught. Then, on coming home, the hungry baby gull knocks at the red spot. This elicits a reflex of regurgitation in mama, and the baby takes the fish from her gullet. All this may sound very simple, but it involves a whole series of most complicated chain reactions with a horribly complex underlying nervous mechanism of the knocking baby and that of the regurgitating mother. All this had to be developed simultaneously, which, as a random mutation, has the probability of zero.[v]

The reliance of evolution upon randomness is so great that Julian Huxley, a staunch evolutionist, calculated the odds of evolution to the level of horse at approximately 1 in 103,000,000.[vi]  To put this in perspective, statisticians typically regard probabilities as remote as 1 in 1050 as essentially impossible.

In light of this problem, Szent-Gyorgyi departed from Darwinian orthodoxy by proposing the concept of syntropy to explain the complex organization of living organisms.  Syntropy, Szent-Gyorgyi hypothesizes, is an “innate force” within living things that resists the natural entropic tendency toward disorder and disintegration.  Of course, this is an ad hoc modification to the evolutionary paradigm.  The concept of syntropy is simply not independently testable.  Moreover, it begs the question: Why do living organisms display this innate tendency to remain organized?

In the past decade, ID theorists, most notably Michael Behe and William Dembski, have brilliantly elucidated the problem with evolutionary theory that has given rise to such desperate proposals as Szent-Gyorgyi’s syntropy and inspired others, including Behe himself, to jump paradigms.  Behe identifies the essence of the problem as “irreducible complexity.”  Living organisms are replete with structures and processes whose functionality could not have been achieved through incremental steps.  In Behe’s words, “an irreducibly complex system cannot be produced gradually by slight, successive modifications of a precursor system.”[vii]  A mousetrap, for instance, is composed of multiple parts—a platform, spring, hammer, catch, and the metal arm that holds the hammer in place.  Without any one of these components, the entire mousetrap is useless.  The same is true, but at a profoundly more complex level, in the world of biology.  Behe details numerous instances of biological irreducible complexity, from bacterial flagella to human eyesight.[viii]

The work of Behe and other ID theorists lays the axe at the root of the Darwinian tree.  But Darwin himself seemed to invite such a line criticism when he declared, “If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.”[ix]  Although ID theorists have identified scores of irreducibly complex systems, the Darwinian camp does not seem to be folding its tents.  This is no surprise, since there is more at stake in this debate than making sense of biology.  The implications of the ID theorists’ critique are metaphysical, even religious in nature.  If all natural explanations of biological complexes fail, then the only rational alternative is supernatural intelligent design, i.e. God.  And for philosophical naturalists, this is an unacceptable alternative.

But why the stubbornness on the part of theistic evolutionists?  Why do they remain steadfast in their Darwinism despite the problem of irreducible complexity?  The explanation, as intimated earlier, lies in their philosophy of science, specifically their methodological naturalism.  And here we see the real danger in this approach when it comes to the issue of origins.  Methodological naturalism rules out—even prior to all inquiry—the possibility of non-natural explanations for the data they study.  Of course, to so prejudice the study of origins, where the very question at issue is whether all life forms can in fact be explained naturalistically, begs the question.  What’s worse, by ignoring an entire domain of causal explanations, methodological naturalism is irrational, at least according to the wisdom of the American philosopher William James.  Regarding rules for truth-seeking, James writes, “a rule of thinking which would absolutely prevent me from acknowledging certain kinds of truth if those kinds of truth were really there, would be an irrational rule.”[x]  But, of course, methodological naturalism is just such a rule for thinking, as it prevents us from acknowledging the truth of supernatural biological design, if that truth is “really there.”[xi]

In addition to the above noted problems with evolution generally (pertaining to paleontology, genetics, physiology and morphology), the theistic evolutionist faces some further problems falling outside the domain of science.  Some of these are theological, pertaining to biblical hermeneutics.  Specifically, can the evolutionary model adequately account for standard interpretations of the Genesis creation narrative, particularly as regards Adam and Eve and the doctrines of the fall and original sin?  I am not referring here to a strict six 24-hour day interpretation of Genesis 1:1-2:3, but to the orthodox Christian teaching that God made Adam and Eve the first human beings, specially formed “in his image,” and that all human beings fell with Adam.  In particular, it seems that the theistic evolutionist must deny the biblical teaching that death resulted from the fall (cf. Rom. 5:12-21).  For if humans evolved through natural selection, then death long preceded Adam and Eve.

Some further issues are metaphysical in nature.  Can the evolutionist make sense of the natural emergence of consciousness, especially as regards the human soul?  For the Christian who believes that humans have immaterial souls, we may ask “How could such a supernatural entity have evolved naturalistically?”  Because this appears inexplicable, many theistic evolutionists affirm physicalism, claiming that our soulish qualities are really nothing more than complex physical features.  However, contemporary philosophers of mind have failed to provide a plausible naturalistic account of human consciousness, and the evidence is mounting that such an account is indeed impossible, that what we call the human soul really is supernatural and therefore demands a supernatural cause.[xii]  But supposing a physicalist account of human consciousness could eventually be provided, there awaits a potentially greater obstacle: accounting for human freedom and rationality.  If we really are nothing more than material beings, then it seems that all of our beliefs and choices are mechanistically determined by physical states.  But this seems to imply that we are essentially machines.  Whence, then, comes human freedom?

Furthermore, as Alvin Plantinga has recently argued, if all of our cognitive faculties resulted from evolutionary processes, having been selected for because of their survival value, then we have little reason to believe that they are reliable in producing true beliefs.[xiii]  Just because a cognitive process has a high survival value does not imply that it is truth-conducive.  So if our minds are simply the result of natural selection, we do not have good reason to think they are at all reliable for producing true beliefs (including our beliefs about evolution).  Thus, if evolution is true, we have reason to be skeptical about all of our beliefs.  It seems that trusting human rationality presupposes some sort of design plan for our cognitive faculties, that our minds have been created in such a way that they tend to produce a preponderance of true beliefs, at least when our minds are functioning properly.  Of course, for the theistic evolutionist, being committed to functional integrity and non-interference from God, such specific design of the human mind is out of the question.  So how can the theistic evolutionist even rely upon her own mind as rational and reliable?

All of this is not to say that no version of the theistic evolutionary perspective could be true.  On the contrary, my own provisional position is mildly evolutionary.  I don’t accept the doctrine of common biological ancestry, but I do believe that natural selection might explain the emergence of new species and perhaps even new genuses of organisms.  It must be borne in mind that the Linnaean taxonomic system in biology is somewhat artificial.  Not all of its classifications (i.e., kingdom, phylum, class, order, family, genus, species) necessarily represent boundaries that cannot be breached via natural processes.  So one might accept the possibility of evolution up to a certain point, say, to the level of families, and yet deny the Darwinian thesis of common ancestry.  Might not God have created certain particular fish, reptiles, birds, (land and sea) mammals, etc., after which natural selection resulted in the proliferation of different organisms within those categories?  Surely something along these lines is possible.  Moreover, it is a reasonable hypothesis given the problems with the extreme positions.  On the one hand, there is evidence for evolutionary change to be found in many plants and animals.  On the other hand, the problems noted above should keep us from extrapolating too far from the relatively minor structural and physiological changes evident in such organisms.  Indeed, this was Darwin’s fundamental mistake.

 

James S. Spiegel is Professor of Philosophy and Religion Taylor University.

NOTES

[i]  Howard J. Van Till, “Is Special Creationism a Heresy?” Christian Scholar’s Review 22:4 (1993): 385.  One serious problem with Van Till’s approach is the low view of providence that it entails.  The orthodox Christian view of providence is that God continually sustains the world from moment to moment (see, for example, Col. 1:17 and Heb. 1:3).  To deny that God “manipulates” creation appears to flout this basic teaching.

[ii] Frederick Hoyle and Chandra Wickramasinghe, Evolution from Space (New York: Simon and Schuster, 1981).  For some excellent analysis and sustained critiques of the chemical evolution hypothesis, see C. B. Thaxton, W. L. Bradley, and R. L. Olsen, The Mystery of Life’s Origin: Reassessing Current Theories  (Dallas: Lewis and Stanley, 1984) and Stephen C. Meyer, “The Origin of Life and the Death of Materialism,” The Intercollegiate Review (Spring 1996): 24-43.

[iii] According to this theory, the “seeds” of life on earth, such as in the form of bacteria and algae, were disseminated by visitors from another planet.  The seminal article, so to speak, proposing this view is F. H. Crick and L. E. Orgel, “Directed Panspermia,” Icarus 19 (1973): 341.  For more information, see the website of The Interstellar Panspermia Society: http://www.panspermia-society.com/.

[iv] Quoted from Jeremy Rifkin, Algeny (New York: Viking Press, 1983), 125.

[v] Albert Szent-Gyorgyi, “Drive in Living Matter to Perfect Itself,” Synthesis 1:1 (1977): 18-19.

[vi] Julian Huxley, Evolution in Action (New York: The New American Library, 1953), 45-46.

[vii] Michael J. Behe, “Molecular Machines: Experimental Support for the Design Inference.” http://www.arn.org/docs/behe/mb_mm92496.htm.

[viii] Michael J. Behe, Darwin’s Black Box: The Biochemical Challenge to Evolution  (New York: The Free Press, 1996).

[ix] Charles Darwin, Origin of Species, 6th ed. (New York: New York University Press, 1988), 154.

[x] William James, The Will to Believe and other Essays (New York: Dover Publications, 1956), 28.

[xi] For further critiques of methodological naturalism see Robert A. Larmer, “Is Methodological Naturalism Question-Begging?” Philosophia Christi 5:1 (2003): 113-130; Stephen Meyer, “The Methodological Equivalence of Design and Descent” in The Creation Hypothesis, ed. J. P. Moreland (Downers Grove, IL: Intervarsity Press, 1994); J. P. Moreland, “Theistic Science and Methodological Naturalism” in The Creation Hypothesis; Alvin Plantinga, “Methodological Naturalism,” Origins & Design 18:1 (Winter 1997): 18-27; idem, “Methodological Naturalism, Part 2,” Origins & Design 18:2 (Fall 1997): 22-33; and James S. Spiegel, “The Philosophical Theology of Theistic Evolutionism,” Philosophia Christi 4:1 (2002): 89-99.  Also, see Steven B. Cowan, “But Is It Science? A Response to Methodological Naturalism” Areopagus Journal 5:1 (January-February 2005): 22-26.

[xii] Several recent works have documented the failure of efforts by contemporary philosophers of mind to “explain” consciousness.  See, for example, John Horgan, The Undiscovered Mind  (New York: The Free Press, 1999); Colin McGinn, The Mysterious Flame (New York: Basic Books, 1999); and John R. Searle, The Rediscovery of the Mind (Cambridge, Mass: MIT Press, 1994).  Although these writers do not opt for a supernaturalist account of mind, their findings are strongly suggestive in this direction.

[xiii] See Alvin Plantinga, Warrant and Proper Function (Oxford: Oxford University Press, 1993), chapter 12.

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