Also featured in the Outlook forum this issue: Intelligent design–a cultural code phrase by Walter R. T. Witschey
Even a casual glimpse at current headlines leaves little doubt that the Intelligent Design debate has become yet another battleground in the culture wars, with culturally-aggressive fundamentalists and equally-militant secularists well represented among the contending parties. Beneath the surface-level politics, however, there are substantial scientific and philosophical issues at play that ought to be of interest to any thinking Christian. It is the purpose of this essay to highlight some of these more substantive issues, lest they disappear beneath the waves of partisan politics.
One of the founding documents of the Intelligent Design Movement is Darwin’s Black Box, by Michael Behe. Those who have seen Intelligent Design linked repeatedly with biblical Creationism in the popular press may be surprised to find that Behe’s book contains no scriptural citations, no references to Genesis, no theological arguments, no appeals to faith, no sweeping rejection of evolutionary theory and no speculation about the nature or identity of a Creator.
What Behe’s book does contain is a lot of biochemistry: technical descriptions of the chemical machinery that underlies life-processes such as blood clotting, immune response, vision, etc. These molecular machines turn out to be vastly complex, Rube Goldberg contraptions whose operation depends on the precise interaction of dozens of large, intricately-structured protein molecules.
Behe contends that while evolutionary processes of random mutation and natural selection can account for much of the living world around us, they cannot explain significant portions of what modern biochemistry has uncovered at the molecular-level of living organisms. Why is this so?
Darwinian evolutionary theory contends that complex systems come into being from simpler precursors by the gradual accumulation of small changes across generations. These changes are preserved because each intermediate form confers some sort of survival advantage on the organism that possesses it. Behe argues that certain biochemical systems could not have arisen in this step-by-step fashion, because tiny changes to any one of the working protein “parts” cause the entire molecular machine to cease functioning.
The working of these complex systems thus has a kind of all-or-nothing quality, which Behe terms “irreducible complexity.” Irreducibly complex systems cannot be the end product of a series of stepwise small improvements, because anything simpler than what we actually see would be non-working, useless junk that could never help an organism to survive.
Behe issues a blanket challenge to his scientific colleagues to propose even remotely plausible speculations about what survival-enhancing intermediate steps could have led to the development of such systems. Lacking any credible proposals from evolutionary theory, he proposes that scientists need to reckon seriously with the possibility that these intricate molecular machines were designed by some sort of creative intelligence.
Behe offers no speculation about the identity of the designer(s). He does propose a scientific program based on his hypothesis, which would involve cataloging biochemical systems in order to separate those that could have arisen through evolution from those that appear to be designed. A complete catalog of irreducibly-complex systems might allow us to construct a profile of a primitive, “designed” life form, from which all the living things we now see could presumably have evolved.
Behe’s proposal has drawn widespread criticism, but the critiques have generally not taken the form of plausible proposals for the evolutionary development of biochemical systems. Instead, a frequent accusation has been that Behe’s proposal is not real science. Behe’s critics contend that real science cannot include God (or a designer) in the list of causes that explain what we see in the world around us. Since genuine science by definition deals only in naturalistic explanations, and since evolutionary theory is the most successful naturalistic explanation available, responsible scientists must assume that evolutionary explanations exist for every biochemical system we see, even though we are presently clueless what they might look like.
Some of these criticisms contain hidden philosophical assumptions that are well worth examining. The critics are absolutely correct in claiming that the western scientific tradition has achieved stunning success by confining its investigations strictly to the realm of naturalistic explanation. As a general working principle, science has focused its attention exclusively on natural, physical causes that it is competent to uncover, and ignored other possible sources of causation like faeries, human choices, or God. On this basis, the defenders of traditional evolutionary theory are correct in claiming that conversations about God are inappropriate for science classrooms, because that is not what science is about. One could perhaps recognize Behe’s own loyalty to this principle in his decision not to speculate about the nature or identify of his inferred designer!
Some of Behe’s critics, however, appear to move from saying that science should stick to naturalistic explanation because that is where its competence lies, to saying that science focuses on naturalistic explanations because they are the only ones that really exist. This is not a claim about the proper domain of science but about the nature of reality. Christians should be cautious about such claims, because they sometimes involve the implicit assumption that God is not real: We assume that evolution must be the explanation for everything we see because we know that a (nonexistent) God could never be the origin of it.
Why couldn’t God have designed certain aspects of living things, as Behe proposes and the current state of the evidence seems to suggest? Concealed beneath the surface of this debate are also powerful philosophical assumptions about the kind of universe we live in.
I fill a teakettle with water and place it on the burner. I know that in a few minutes the kettle will whistle, because the water inside is boiling. Physical laws governing the behavior of water, gas flames and metal pots make the whistling kettle a necessary outcome of natural cause-and-effect.
After the water boils I pour it into a cup. The fact that the cup contains Earl Grey rather than chamomile tea is a contingent development. It is the product of my own free choice and not something that the laws of physics might explain.
Theologians such as T.F. Torrance have suggested that the Christian doctrine of creation leads us to expect that the universe as a whole is contingent. The Bible portrays creation arising as a result of God’s free choice, rather than as the product of some lawful necessity. A universe produced by God’s free decision would be contingent because its existence would not be explainable strictly on the basis of physical law. One would not want to claim that Christian faith was incompatible with a necessary universe, but the correlation between divine creation and a contingent universe is surely suggestive.
Is the development of life on this planet a necessary or contingent event? Is it the inevitable outcome of a set of original conditions on the young planet earth, with living organisms evolving as inevitably as my kettle comes to a boil? Or is the appearance of life a contingent event, the product of creative intelligence or miraculous happenstance that cannot be explained simply as the product of physical cause-and-effect?
Those among Behe’s critics who claim that all aspects of life must be explainable by evolution may be assuming that the development of life is a necessary phenomenon. Like the appearance of the whistling kettle, it is entirely explainable as the outcome of natural, physical processes. Behe’s claim, to the contrary, is that life’s development includes contingent events that, like my choice of Earl Grey tea, are not wholly explainable by physical laws.
Is there a reason to think one assumption is more “scientific” than the other? One might argue that it is simply a question of what actually happened when life arose, and a proper science should be capable of grasping the truth of things, whatever that truth might be.
There is some reason to hope that these questions will eventually be resolved by scientific means. If Behe is right and the appearance of life is a contingent event, one would expect the search for plausible evolutionary explanations to come up empty-handed no matter how long the investigation continued. In this light one could say that continuing failure to provide such explanations would count as evidence in Behe’s favor, though how long it would take to establish his conclusion as probable is a judgment call.
There is also a direct connection between Behe’s claims and questions about the existence of extra-terrestrial life. If Behe’s critics are right and life is a necessary outcome of natural evolutionary processes, then life should arise as inevitably as my teapot comes to a boil anywhere in the universe where earth-like conditions are present. The fact that we have not registered evidence of a universe teeming with life surely counts in Behe’s favor, though given the limitations of our knowledge in this area such results are far from conclusive.
It is interesting to note in closing that Behe’s biochemical systems are not the only place where science has uncovered phenomena that seem to point beyond the physical universe for their explanation. Cosmologists studying the origins of the universe have recently uncovered dozens of coincidences in the laws of physics and chemistry. Together these coincidences convey a striking impression that the universe has been extraordinarily fine-tuned in order to make carbon-based organisms like us possible. Are these “anthropic coincidences” the contingent products of a designing intelligence, or are they the necessary outcome of physical laws whose existence and operation we do not yet understand? This second front in the intelligent design discussion raises many of the same questions as Behe’s work, and suggests that the questions Behe raises are not confined to only one area of scientific investigation.
In sum, while the Intelligent Design debate is surely a political and ideological battleground, it also involves serious scientific and philosophical questions about the nature of reality and the kind of universe we live in. We should give thanks to God for the privilege of living in such interesting times!
Mark Achtemeier is an associate professor of systematic theology at the University of Dubuque (Iowa) Theological Seminary.