More Options

One Longsome Argument

Article

Dennis R. Trumble

Volume 29.2, March / April 2005

By any objective measure, the evolution of species ranks among the most successful scientific theories ever. So why is the message not getting through?

Charles Darwin liked to describe the origin of species as “one long argument,” but his extensive treatise in support of biological evolution now seems painfully brief compared to the argument that has followed in its wake. Indeed, never in the history of science has a more prolonged and passionate debate dogged the heels of a theory so thoroughly researched and repeatedly validated. And the end is nowhere in sight. Despite all evidence to the contrary, a large portion of the world’s population continues to cling to the belief that human beings are fundamentally different from all other life forms and that our origins are unique. It’s a lovely sentiment to be sure, but how is it that so many people continue to be drawn to this thoroughly discredited notion?

Like most mystic mindsets, creationist beliefs are normally instilled at an early age, nurtured by well-meaning parents and sustained by religious organizations whose vested leaders are traditionally loath to amend church doctrine in the face of emergent scientific facts. Though seemingly antithetic to the inquisitive nature of our species, the rote acceptance of received wisdom has been a hallmark of human culture almost from the get-go, arising initially as a benign behavioral adaptation geared to promote the rapid transfer of communal survival skills to our young hominid forebears. It was only with the advent of modern civilization that this age-old habit finally began to outlive its usefulness and yield serious negative consequences-most notably by granting gratuitous momentum to all kinds of ill-conceived notions about how the world is “supposed” to work. Today, this surge of ideological inertia remains a surprisingly powerful force, pushing beliefs as impossibly anachronistic as geocentrism and flat-Earth cosmology past the ramparts of the enlightenment to foul the fringes of modern thought.

Fortunately, unlike the veiled forces that impart momentum to particles of mass, the impulse that propels incongruous ideas from one generation to the next is fairly transparent at its base. After all, youngsters imprinted with self-flattering beliefs are understandably reluctant to amend them later in life owing to the special status and privileges they bestow. And once someone has grown accustomed to the hollow pleasures of this egocentric world view, it’s easy to see how these inflated beliefs would come to be shielded from the prickly barbs of reason by a panoply of family, friends and other like-minded folks, all of whom harbor the same inscrutable notions (mystery loves company).

Although this perpetual pattern of natal indoctrination and communal reassurance does not begin to encompass the full psychosocial breadth of this phenomenon-especially where adult converts are concerned-it does go a long way toward explaining the inordinate longevity of creationist mythology and why so many intelligent, well-educated, and otherwise rational people appear unable to step back and examine certain beliefs with a critical eye. Because creationist beliefs are both deeply rooted and profoundly comforting, it isn't hard to understand why certain people feel compelled to enlist any and all means at their disposal to discredit Darwin’s theory. Nor is it difficult to imagine the sense of frustration they must feel when repeatedly told by scientists that their arguments are fundamentally flawed.

Problem is, most folks-including many of the more learned among us-don't understand the basic workings of science well enough to appreciate how feeble the arguments against evolution really are. If they did, they would realize that the scientific process is not about gathering data to prove a favored hypothesis but instead involves the testing of ideas against the totality of real-world observations. Creationists turned amateur scientists almost always fail to grasp this essential scientific precept and so unwittingly launch from false premises all kinds of pseudoscientific arguments in support of special creation. In fact, if there’s one reason why creationist critiques are so consistently misguided it’s that adherents generally presuppose that special creation is true and then sift the evidence for clues to support that supposition-a recipe for self-deception that stands in stark contrast to the scientific method, which mandates that fresh hypotheses be derived from all available evidence.

Were this fundamental misconception to be extinguished in a sudden wave of scientific literacy, the illusory evidence that thinking creationists use to anchor their beliefs would be swept away in an instant, leaving precious little demand for the writings of creation “scientists.” As it is, however, an ungodly amount of literature is being published by the sectarian faithful in a spirited attempt to preserve mankind’s privileged place in the grand scheme of things. Whether knowingly or not, creationists of every stripe have come to rely on an assortment of pseudoscientific arguments to legitimize their efforts to unravel the fabric of evolutionary theory, hoping against hope that the extensive tapestry woven by seven generations of scientists might somehow dissolve with the tug of a few loose threads. Unfortunately, as the weave of evolutionary theory has continued to tighten and expand, the number and variety of confused arguments in defense of creationism and intelligent design have only risen to keep pace.

One popular approach enlisted by creation “scientists” is the classic all-or-nothing argument wherein proponents claim that nothing in science can be known with confidence until every last detail is described with absolute certainty. Appealing largely to those unschooled in the scientific method, critics point to such nonissues as gaps in the fossil record, poorly understood aspects of gene function, and the mystery of life’s origins as reasons to view evolutionary theory as speculative or provisional. What they fail to appreciate is that scientific theories are built solely upon evidence that is actually available for study and so cannot be refuted by speculation regarding those clues that remain hidden. As long as a theory remains consistent with observed phenomena and yields valid predictions, it must be considered a viable explanation regardless of what remains to be discovered. Thus, it is entirely irrelevant that gaps in the fossil record exist, but vitally important that those fossils that do exist make sense in the context of evolution. A single hominid fossil found among the trilobites of the Burgess Shale, for instance, would immediately throw Darwin’s theory into doubt. Likewise, the fact that certain aspects of molecular genetics remain to be fully described in no way negates the fact that the substantial amount that is known about gene function is entirely consistent with evolution as we understand it today.

Yet despite the proverbial admonition against doing so, many still view the absence of evidence as evidence of absence and remain all too eager to fill this fictional void with the narrative of their choosing. Indeed, this particular brand of argumentum ad ignorantiam has long been a mainstay for creationists looking to wedge their cosmology between the narrowing gaps of scientific knowledge (an increasingly difficult task). But issues of legitimacy aside, because this fallacy has sired so many specious claims over the years it seems only fitting that the mother of all such “arguments to ignorance” should stem from the granddaddy of all biological data gaps: the evolution of single-celled life forms.

Because no physical body of evidence exists to document the beginning of life on Earth, this information gap has proven to be a wildly popular (albeit wholly inappropriate) foil for those seeking to discredit evolutionary theory. In truth, the origin of life is an issue entirely separate from the origin of species, rendering this otherwise important question utterly irrelevant as far as the veracity of natural selection is concerned. Whether the first primitive life form arose from known physical processes or was somehow willed into being through means beyond our understanding, evidence that all life on Earth descended from simple primordial beings remains just as compelling, and the myth of independent creation just as untenable.

But even this slender refuge for creationist sentiment has now begun to evaporate under the light of modern scientific scrutiny, for although Earth’s original life forms left no physical evidence for scientists to examine, credible hypotheses regarding the spontaneous formation and assembly of self-replicating molecules have been proposed and tested nonetheless. Laboratory experiments and astronomic observations suggest that key organic compounds were present in abundance shortly following Earth’s formation and that natural chemical affinities and mineral scaffolds may have acted in concert to produce the simplest of biochemical copying machines. In 1953, Stanley Miller became the first to demonstrate that amino acids and other organic molecules could have formed through chemical means in prebiotic oceans capped with an atmosphere of ammonia, methane, and hydrogen gas. Although geochemists now question Miller’s assumptions regarding the reducing power of the prebiotic atmosphere (Bada 2003), reducing environments may well have existed in isolated pockets on the embryotic Earth (near volcanic vents for instance). Moreover, many of these same organic compounds have been found to exist among interstellar dust clouds and meteorites, suggesting that life’s building blocks may have been delivered to Earth on the backs of icy comets and carbonaceous asteroids.

Based on these and other findings, biochemists have proposed several plausible mechanisms by which these compounds may have coalesced of their own accord into the precursors of life. Experiments confirm that layered mineral deposits can attract, concentrate, and link organic molecules and that certain clays may function as scaffolding for assembling the molecular components of RNA (Hazen 2001). Crystalline templates have also been proposed as possible means of primitive protein assembly, their mirror-image surface structure accounting for the curious predominance of “left-handed” amino acids found in all creatures living today. These and other minerals have also been shown to facilitate the sequence of chemical transformations needed to spark life, acting as sheltered containers (feldspar), catalysts (magnetite), and iron sulfide reactants (pyrite). What’s more, a complex mixture of organic compounds formed within simulated interstellar ices has recently been observed to spontaneously form cell-like vessels when immersed in water (Dworkin 2001), providing yet another viable mechanism by which particles awash in a dilute prebiotic soup might have assembled themselves into crude cells.

Although the precise sequence of events will never be known with absolute certainty, these and similar experiments strongly suggest that the earliest terrestrial life forms arose spontaneously and in accordance with the known laws of nature. In short, everything we have come to understand about our world suggests that living creatures are a natural consequence of the laws that govern the physical universe-no more anomalous than the matter they comprise or the space they occupy. Yet despite all efforts to disseminate this hard-earned knowledge, a broad swath of creationist sentiment lingers on, fueled by well-worn arguments ranging from the philosophical and dogmatic to the confused and plain disingenuous. The great majority of these objections, however, quickly collapse under even the most cursory examination.

Many of the “scientific” arguments for intelligent design, for instance, invoke common misconceptions about how the physical world really works, as in the classic “watchmaker” argument wherein nature is assumed to act randomly and possess no organizational tendencies. Given this false premise, it is a simple matter to show that complex molecular structures could never have formed by chance alone any more than a factory whirlwind could assemble a Mercedes Benz from its component parts. But anyone with a basic understanding of chemistry knows full well that such analogies do not apply to atoms and molecules. If the physical sciences have taught us nothing else, it’s that the world of the very small is surprisingly counterintuitive. Processes in the realm of the microscopic simply do not behave as one might expect based on our experience living on the macroscopic plane. Electric charges, energy barriers, and nuclear forces all dominate the realm of the minuscule and compel individual atoms to form stable chemical bonds with neighboring elements, blindly building molecular structures of every possible type and complexity that the laws of physical chemistry will allow.

Objects large enough to arouse our naked senses, on the other hand, behave quite differently. Because they exhibit no special affinity for one another, the scattered components of a disassembled watch will never coalesce of their own accord-the odds against such haphazard assemblies are simply too long. Nature, however, does not act without organizational tendencies nor are living organisms randomly assembled. There is now ample reason to believe that simple unicellular life forms arose through processes endemic to the life-friendly universe we occupy and that more sophisticated beings slowly emerged from these modest beginnings. Indeed, all complex organisms on Earth (including humans) begin life as single cells that multiply, differentiate, and ultimately mature to assume the form of its parent-all in strict accordance with the natural laws of biochemistry.

The contention that evolution somehow violates the second law of thermodynamics is another popular fiction that has endured through widespread confusion over a fundamental physical concept-in this case, thermodynamic entropy. Couched in the plainest possible terms, the second law simply states that energy tends to spread from areas where it is concentrated to areas where it is not. Although it is not widely recognized, this phenomenon is an integral part of our everyday experience and shapes our commonsense expectations. Because energy always flows from where it is concentrated to where it is more diffuse, we expect, say, a warm bottle of GewŸrztraminer to chill when lowered into a bucket of ice water. In this instance, thermal energy will flow from the tepid wine to the surrounding fluid until both reach a common temperature and an energetic balance is achieved. Like the ice bucket and its contents, self-contained systems receiving no external energy will always experience a net increase in the diffusion of thermal energy, or a rise in thermodynamic entropy, resulting in lower energy gradients and less potential to do work.

Regrettably, this same term has also come to be used in a statistical context involving the distribution of particles placed in random motion within a closed system-a situation that has bred a great deal of confusion. Unlike thermodynamic entropy, which defines energy distributions, “logical” entropy describes the probability that randomly distributed particles will assume a certain configuration or organized pattern. Ordered systems with low entropy values may appear to the casual observer to contain discernable patterns whereas high entropy systems seem more disorganized. Gas molecules distributed within an enclosure, for example, are said to exhibit greater entropy when they are scattered than when they are grouped together. Why? Because although every possible pattern of molecules has an equal chance of occurring, there are a great many more ways to define a diffuse pattern than any given clumped arrangement and, as physicist Richard Feynman was keen to observe, logical entropy is simply “the logarithm of that number of ways.”

Despite the fact that thermodynamic and logical entropy are wholly independent concepts, many laymen-and a few scientists who really should know better-have nonetheless come to confuse and intermingle the two, transforming the second law of thermodynamics into a fictitious “law of disorder” that ostensibly explains why all material things decay and fall apart. In truth this has nothing to do with the second law of thermodynamics and even misuses the concept of logical entropy in that it attempts to explain large-scale phenomena. There is, in fact, no such universal mandate of decay that precludes the spontaneous formation of complex assemblages. Just because all complex systems will eventually break down as energy throughout the cosmos becomes evenly distributed doesn't mean that some interesting patterns can't take shape in the meantime.

Those who argue this point from a purely energetic standpoint are somewhat less confused but just as easily refuted. The fact that the amount of energy available to do work must always decrease in a closed system would indeed be a serious impediment to the evolution of life if our planet were isolated from all external energy sources, but one need look no further than our companion star to see that such is not the case. Energy is constantly being delivered to the thin shell of our biosphere both from above, in the form of sunlight, and below, via heat generated by Earth’s radioactive core, providing ample energy to fuel the assembly of structured molecules. Moreover, while it is true that the overall entropy of an isolated system cannot decrease, the entropy of certain parts of a system can, and often do, spontaneously decrease at the expense of even greater increases in adjacent regions, as with the formation of crystalline salts and snowflakes. Besides that, millions of chemical compounds including water, cholesterol, and DNA actually carry less energy than the elements they contain (possessing “negative energies of formation” in scientific parlance). In these cases, the second law of thermodynamics actually favors the impromptu formation of complex structured molecules due to their tendency to disperse energy as they coalesce.

Another threadbare canard spread by the creationist camp is that biological evolution is still not widely accepted within the scientific community-a ruse for which competing evolutionary hypotheses are offered up as evidence. The truth of the matter is quite the opposite. The fact that biologists support alternate hypotheses regarding specific evolutionary mechanisms no more challenges the reality of evolution than Einstein’s relativistic views threatened the existence of gravity. Whether evolution proceeds in fits and starts as envisioned by the punctuated equilibrium model or progresses with more stately regularity, each competing hypothesis simply seeks to explain a certain aspect of evolution in a plausible way. The overarching framework of evolution itself, however, remains astonishingly consistent with the huge body of evidence accumulated to date. Far from being the object of scientific debate, the evolution of species is actually no more, and no less, than the collection of observed facts that these hypotheses are meant to explain. Gene flow, frequency dependence, and punctuated equilibrium are but three possible mechanisms put forward to explain the nature of this overarching phenomenon. Which, if any, of these hypotheses survive the test of time bears no influence on whether modern species are the product of biological evolution-the evidence in this regard, now comprising countless independent observations, is simply overwhelming. It is only the processes that drive the phenomenon of evolution that remain the object of scientific scrutiny.

Unencumbered by the rules of scientific inquiry, others proclaim with total aplomb that evolution can never be truly validated until major speciation events (the transformation of land mammals into whales for instance) are observed directly. In this case, what is ignored is the important fact that reliable scientific evidence is not limited to firsthand experience of real-time events but includes all forms of physical clues. The folly of this argument becomes evident when one considers that knowledge of galaxy formation, stellar composition, and subatomic particles would be impossible if researchers were to adopt similar rules of evidence across the whole of science. But why stop at the boundaries of academia? Imagine for a moment the chaos that would ensue within the criminal justice system if such an unreasonable burden of proof were placed on prosecutors! Indeed, as many jurors would no doubt attest, it is often the physical evidence that proves most compelling in a court of law, eclipsing even eyewitness accounts that can be tainted by errors of interpretation or outright deceit.

Beliefs maintained through the narrow interpretation of isolated facts or held in default against evidence not readily understood can be called any number of things, but “scientific” is certainly not one of them. As these few examples illustrate, the myriad approaches adopted by creation “scientists” in their attempts to undermine evolutionary theory are indeed quite creative but hardly scientific. As has been demonstrated time and again, evidence carefully sifted can be enlisted to endorse practically any supposition so long as the preponderance of contrary clues are ignored and the rules of sound scientific practice are suspended. It is precisely this brand of exclusionary thinking that enables young-Earth devotees to dismiss mountains of physical evidence while defending their assertions with such flawed assumptions as constant population growth and the linear decay of Earth’s magnetic field (both demonstrably false). Likewise, partisans who claim that evolutionary processes have never actually been observed inexplicably dismiss the scientific literature where such observations have been reported in abundance. In truth, physical adaptations to environmental pressures have been documented in hundreds of modern species from bacteria and fruit flies to birds, squirrels, and stickleback fish (Pennisi 2000). Even Darwin’s own finches have been caught in the act of adaptation thanks to decades of meticulous study spearheaded by Princeton biologists Peter and Rosemary Grant.

A full accounting of the ways in which the scientific method has been manipulated to promote creationist sentiment would doubtless occupy many volumes, but in no instance has a legitimate scientific case ever been made to countermand the notion that, as Darwin phrased it: “from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”

References:

  1. Bada, Jeffrey L., and Antonio Lazcano. 2003. Prebiotic soup-revisiting the Miller experiment. Science 300:745-746.
  2. Dworkin, Jason P., David W. Deamer, Scott A. Sandford, and Louis J. Allamandola. 2001. Self-assembling amphiphilic molecules: Synthesis in simulated interstellar/precometary ices. Proceedings of the National Academy of Sciences 98(3): 815-819.
  3. Hazen, Robert M. 2001. Life’s rocky start. Scientific American April: 77-85.
  4. Pennisi, Elizabeth. 2000. Nature steers a predicable course. Science 278: 207-208.

Dennis R. Trumble

Dennis R. Trumble is Senior Bioengineer in the Department of Cardiothoracic Surgery at Allegheny General Hospital (Pittsburgh, Pennsylvania) and Research Instructor of Surgery at Drexel University College of Medicine. Correspondence may be addressed to D.R. Trumble, Cardiac Surgery Research, Allegheny General Hospital, 320 East North Avenue, Pittsburgh, PA, 15212.