IS EVOLUTION "JUST A THEORY"?
by Lenny Flank
(c)1995
One of the most common accusations heard from creationists is that "evolution is only a theory and hasn't been proven". Such assertions are also heard from conservatives who give political support to the creationists. For instance, during the 1980 Presidential campaign, Ronald Reagan told an audience, concerning evolution, "Well, it's a theory--it is a scientific theory only, and it has in recent years been challenged in the world of science and is not yet believed in the scientific community to be as infallible as it was once believed." (cited in Berra 1990, p. 123, Wills 1990 p. 120, and Eldredge 1982 p. 28)
This accusation demonstrates a basic ignorance of the methods and principles of science. The scientific method holds as a matter of course that all conclusions are tentative, and that nothing can ever be absolutely proven to a certainty. Every conclusion reached by any scientist must always include, even if it is only assumed, the unspoken preface that "This is true only to the best of our current knowledge". Science does not deal with absolute truths; it deals with hypotheses, theories and models. The distinction between these is important in understanding and in countering creationist arguments, since the word "theory" also has a popular usage that is quite different from its scientific meaning (the vast majority of the US population--some studies have indicated as high as 95%--are in essence scientifically illiterate, and have only the vaguest grasp of modern scientific thinking, and the creationists always make a point of appealing to this popular ignorance).
In the popular view, the word "theory" means simply something that is unproven--an assertion which may or may not be true. It is this meaning which the creationists refer to when they assert that evolution is "just a theory", the implication being that, if evolution hasn't been proven, then it should have no more standing than creation "science". In science, however, the word "theory" has a very definite meaning. Under the scientific method, the first step in investigation is to gather data and information, in the form of verifiable evidence. Once data has been gathered, the next step is to form a hypothesis which would explain the data. This hypothesis is, quite simply, nothing more than an intelligent guess. (A hypothesis is, in fact, the closest scientific term to what most people mean when they say "theory").
Once a hypothesis has been formed, it is compared against the data (both old and new) to see how well it fits with the established facts. If the hypothesis is contradicted by the data, then it must be either modified and tested again, or discarded completely and a new hypothesis formed. Once a hypothesis has passed the test of verification through data, it becomes a scientific theory--i.e., it becomes an established framework within which to interpret the relationship of various bits of raw data. On the basis of this theory, new hypotheses are formed, and areas in which new data may be gathered are identified. If the theory continues to correctly explain new data (and indeed serves to correctly predict the outcome of scientific experiments), it is said to have a high degree of reliability. Such a theory is not a mere supposition or guess; it is a hypothesis that has been verified by direct experimentation and which has demonstrated a high degree of predictive ability.
When a related group of theories are correlated to one another and demonstrate the ability to be predictive and to explain the data, they form a scientific model. Models are the intellectual framework within which vast areas of particular data are explained and described. They also serve to indicate potential new areas of research and new hypotheses which can be tested to see if they can be integrated into the model.
An example may help to illustrate these distinctions. Observational data indicates to us that we can see the masts of tall ships while they are still far out on the horizon, before we can see the deck or the hull. We can also observe that the shadow of the earth, cast upon the moon during a rare eclipse, appears to be circular. We can therefore formulate the hypothesis that the earth is round. This would explain all of our data. Using this hypothesis, we can predict that, if the earth is indeed a sphere, we should be able to sail completely around the earth without falling off or coming to an edge. And, if this experiment is performed, we find that we can indeed do so. Our hypothesis has now been verified by experimentation, shows itself capable of correlating a variety of disparate data, and shows an ability to be predictive, and is therefore established as a scientific theory, the Theory of the Round Earth.
If we combine our theory of the round earth with other theories such as the theory of a round moon and a theory of heliocentrism, we can formulate a model--the moon orbits around the earth, the earth orbits around the sun, and all are part of a system of planets orbiting around a central star. This is the model of the heliocentric solar system.
Please note that none of this is to be treated as an absolute fact. It is entirely possible that some later observation or data will completely upset our model. Many times, a model must be modified and altered in order to explain new data or to expand its explanatory power. No scientific model can be viewed as an absolute proof. Perhaps at some point in time the shadow of the earth upon the moon will be seen to be a square, or perhaps one day we will see that the moon does not really revolve around the earth. However, based upon all of the data we possess currently, we can conclude that neither of these possibilities is very likely, and we are justified in having a high degree of confidence in the solar system model. Although it has not been (and cannot logically be) proven to an absolute certainty, it has been verified by every experiment we have conducted so far, and it has proven to have profound predictive power.
This model then becomes a basis on which to formulate new hypotheses and to investigate new areas of research. As various scientists produce new data and formulate new theories and hypotheses, a consensus will be reached about which theories are better suited to the data and which have a higher degree of confidence. In this manner, the model is constantly being modified, improved and expanded in order to encompass more and more data. Scientific models can never be stagnant--they are constantly changing and expanding as our knowledge of the universe increases.
Thus, scientific models can never be viewed as "the truth". At best, they are an approximation to truth, and these approximations become progressively closer to "the truth" as more testing of new evidence and data is done. However, no scientific model can ever reach "the truth", since no one will ever possess knowledge of ALL facts and data. As long as we do not have perfect and complete knowledge, our scientific models must be considered tentative, and valid only within the current limits of what we know.
The current theories of evolutionary mechanisms (Darwinian gradualism through natural selection, punctuated equilibria and neutralist evolution) together constitute a scientific model. This model has survived (with some modifications) every experimental test, and has not been invalidated by any data or evidence we now possess. Evolutionary theory has demonstrated an ability to correlate and explain a wide variety of disparate data with a high degree of confidence, and has proven to have the ability to predict experimental results and to point out new areas that may be investigated for new data. As a scientific theory, the theory of evolution has the same standing and authority that atomic theory, the theory of relativity and the theory of quantum physics possess.
As a complement to labelling evolution as "just a theory", the creationists also like to refer to their own particular outlook as a "model". Examination will quickly show that this is simply not true--creationism is not a scientific model in any sense of the word. Scientific hypotheses, theories and models are all based upon several fundamental criteria. First, they must explain the world as it is observed, using naturalistic mechanisms which can be tested and verified by independent observation and experimentation. Although the existence of God is not necessarily denied by science, supernatural explanations which are based upon the unseen actions of God are excluded from science as a matter of necessity. As biologist J.B.S. Haldane pointed out, science is dependent upon the assumption that the world is real and operates according to regular and predictable laws, which are not changed from moment to moment at the whim of supernatural forces: "My practice as a scientist is atheistic. That is to say, when I set up an experiment I assume that no god, angel or devil is going to interfere with its course." (cited in Montagu, 1984, p. 241) Geologist and theologian Dr James Skehan also notes, "I undertake my scientific research with the confident assumption that the earth follows the laws of nature which God established at creation . . . . My studies are performed with the confidence that God will not capriciously confound scientific results by 'slipping in' a miracle!" (Strahler, 1987, pp. 40-41)
In a manner similar to that of science, the actions of supernatural entities are also excluded from the legal arena--no person is permitted to argue in a US court that they are not responsible for a crime because Satan was in control of them, or that such and such a crime happened because it was the will of God. Neither system denies the existence of God, but both exclude God as an explanatory mechanism.
The creationist idea that God divinely created the universe may or may not be true, but, by postulating a supernatural event which occurs outside of the natural laws of the universe, such an idea places itself firmly outside the realm of science. There is simply no experiment which can verify any of its assertions and no predictions of future data that can be drawn from this hypothesis, and those who hold such conclusions can do so only on the basis of faith. This is fine for a religious outlook or an ideology, but it has nothing at all in common with science.
Another characteristic of science is that it must be falsifiable. As we have seen, it is not possible to "prove" that any scientific model is absolutely true and correct. It is, however, quite possible to prove that any given scientific model is not correct--that is, it can be conclusively shown to be false. The evolution model, for instance, could be falsified in any number of ways--a new species could be reliably observed to suddenly POOF! into existence from nowhere, for instance. On a more realistic level, the evolution model would be conclusively falsified if any of the three basics we pointed out earlier--variation, heritability or selection, were shown by experiment to be invalid (i.e., if some genetic mechanism were to be found which made it chemically impossible for mutations to occur in the DNA, or for any such mutations to be passed down from one generation to the next). The evolutionary model would also be falsified if the fossil remains of a fully modern human being or a flowering plant were to be reliably found in strata that have been dated to the Cambrian period of earth's history, or the Devonian, or the Permian, or if it were to be conclusively shown that all fossils found to date are elaborate fakes, planted by an international conspiracy of evolution scientists to impose secular humanism upon the earth. So far, however, no evidence has been reliably presented, by the creationists or by anyone else, which falsifies the evolution model. Every experiment that has been performed and every bit of data which has been collected has tended to confirm its validity.
And how does creation "science" fare when put to this test? The central tenet of creation "science" is that God created the universe out of nothing, by Divine fiat. This "model" is, however, completely unfalsifiable. There is no test or experiment which can conclusively show that God does not exist, or that creation did not occur. Since, by definition, God is capable of doing or accomplishing anything, there is nothing that can be pointed to that God cannot have done, and therefore the hypothesis itself is unfalsifiable. Any potential problem with the "creation model" can be (and very many times has been) explained away with a wave of the hand, with the simple assertion, "God did it that way." Because the tenets of scientific creationism cannot be tested, investigated or falsified, and because they invoke supernatural entities as explanatory mechanisms, they cannot be considered to be a scientific model.
Some creationists, moreover, have turned this criticism into a virtue, and have argued that, since it cannot be proven that Divine Creation did not happen, then it must be assumed that it did happen. This, of course, violates basic logic. One could just as easily assert that life on earth is the result of experiments by extra-terrestrial biologists from the planet Melmac, who seeded the primordial earth with artificial biological compounds. There is no way to test or verify this hypothesis, and thus no way to prove it wrong. This, however, means only that it is not a valid scientific theory--it does not mean that there must of necessity be Melmackian exo-biologists.
In court, the creationists have argued that their view is not necessarily religious, since it refers to "a creator", not to "God". During the Arkansas trial, for instance, the defenders of the Balanced Treatment Act argued, "There is nothing inherently religious about the terms 'creator' or 'creation', as used in the context of Act 590. Act 590 is concerned with a non-religious conception of 'creation' and 'creator', not the religious concepts dealt with in the Bible or religious writings. . . All that creation- science requires is that the entity which caused creation have power, intelligence and a sense of design." (Defendant's Trial Brief, McLean v Arkansas, 1981) This argument is nonsensical, and it has been rejected by every judge who's ever heard it.
In their lucid moments, the creationists are quite willing to concede that their "model" is not scientific. Henry Morris, the founder of the Institute for Creation Research, openly admits, in his textbook Scientific Creationism:
"A. Creation cannot be proved
1. Creation . . . is inaccessible to the scientific method.
2. It is impossible to devise a scientific experiment to describe the creation process, or even to ascertain whether such a process can take place." (Morris, Scientific Creationism, 1974, p. 5)
"The creationist model does presuppose a God, or Creator, who did create things in the beginning." (Morris, Scientific Creationism, 1974, p. 4)
Another ICR member, Duane Gish, writes, in his book Evolution? The Fossils Say No!:
"Creation is, of course, unproven and unproveable by the methods of experimental science. Neither can it qualify, according to the above criteria, as a scientific theory, since creation would have been unobservable and would as a theory be nonfalsifiable." (Gish, 1978, p. 21)
"We do not know how the Creator created, what processes He used, for He used processes which are not now operating anywhere in the natural universe. . . . We cannot discover by scientific investigations anything about the creative processes used by the Creator." (Gish, 1978, p. 40)
Lately, the creationists have taken to arguing that, while creationism is indeed not a science, neither is evolution--evolution is, they say, a "religion" of "secular humanism". As Gish puts it in a letter to Discover magazine: "Creationists have repeatedly stated that neither creation nor evolution is a scientific theory (and each is equally religious)." (Gish, Discover, July 1981, cited in Overton Opinion) Paul Ellwanger says, "We're not making scientific claims for creation, but we are challenging evolution's claim to be scientific." (Attachment to Ellwanger Deposition, McLean v Arkansas, 1981, cited in Overton Opinion) Ellwanger was, ironically, the author of Arkansas Act 590, which required creationism to be taught as a "science". This issue was settled in 1994, when a Federal Circuit court ruled, in Peloza v Capistrano School District, that "evolutionism" was not a religion, and teaching evolutionary theory in a science class was not an interference of anyone's religious beliefs.
The creationists have yet to explain why, if they now concede that creation is not a scientific model, they did make that claim when the Arkansas anti-evolution law was passed, or why they have referred to themselves as "scientific" creationists, or why they have demanded for several years that their outlook be treated as a "science" and not as a mere religious dogma. This tendency to say completely contradictory things is typical of the creationist movement--their story changes according to the needs of the moment, with no apparent concern for internal consistency (first, creationism was openly religious, then after the Supreme Court ruled that religious outlooks cannot be taught in public schools, creationism became a "science" that was just as valid as evolution, and after that argument was tossed out of court, creationism became a religion again, but now evolution became a religion too-- a religious faith that can't be falsified--which doesn't stop creationists from presenting the scientific evidence which they claim proves evolution false.).
The cynicism and intellectual dishonesty of the creationist movement was best illustrated by documents presented during the Arkansas trial, which showed that the creationists were advising potential witnesses to downplay the religious dogma behind creationism in an attempt to avoid having the law declared unconstitutional. Paul Ellwanger, the creationist who actually drafted the Arkansas law, wrote to one supporter: "It would be very wise, if not actually essential, that all of us who are engaged in this legislative effort be careful not to present our position and our work in a religious framework. For example, in written communications that might somehow be shared with those other persons whom we may be trying to convince, it would be well to exclude our own personal testimony and/or witness for Christ, but rather, if we are so moved, to give that testimony on a separate attached note." (Attachment to Ellwanger deposition, McLean v Arkansas, 1981, cited in Overton Opinion) In another letter, Ellwanger wrote: "We'd like to suggest that you and your co- workers be very cautious about mixing creation-science with creation-religion. . . Please urge your co-workers not to allow themselves to get sucked into the 'religion' trap of mixing the two together, for such mixing does incalculable harm to the legislative thrust." (Attachment to Miller deposition, McLean v Arkansas, 1981, cited in Overton Opinion).
And in yet another letter, he says, "If you have a clear choice between having grassroots leaders of this statewide bill promotion effort to be ministerial or non- ministerial, be sure to opt for the non-ministerial. It does the bill effort no good to have ministers out there in the public forum, and the adversary will surely pick up at this point. . . . . " (Attachment to Ellwanger Deposition, McLean v Arkansas, 1981, cited in Overton Opinion).
At the same time that the creationists were urging their supporters to downplay the religious basis of their outlook, they made no secret of their religious aims when appealing for funds or for political support among supporters or conservative legislators. Much of the creationist literature openly declares that the motives behind the "scientific" creationists' attacks on evolution are religious and moral, not scientific. Ellwanger, the person who wrote the Arkansas anti-evolution law, admitted in a letter to the legislator who sponsored it for him, "I view this whole battle as one between God and anti-God forces." (Attachment to Ellwanger Deposition, McLean v Arkansas, 1981, cited in Overton Opinion) Georgia Judge Braswell Dean, a creationist supporter, declared, "This monkey mythology of Darwin is the cause of permissiveness, promiscuity, pills, prophylactics, perversions, pregnancies, abortions, pornotherapy, pollution, poisoning, and proliferations of crimes of all types." (Time Magazine, March 16, 1982, p. 82)
The Creation Science Research Center has declared that its "research" has proven that the scientific model of evolution is responsible for "the moral decay of spiritual values, which contributes to the destruction of mental health", as well as "a widespread breakdown in law and order" (Creation Science Report, April 1976, cited in Numbers, 1992, p. 285). Evolutionary theory, the CSRC pontificates, is directly responsible for "divorce, abortion, and rampant venereal diseases." (Segraves, The Creation Report, 1977, cited in Numbers, 1992, p. 285)
Apparently, creationists seem to think that none of the evils of the world existed until Darwin published On the Origin of Species in the mid-19th century. Unfortunately, the creationists have given us no written statement about which varieties of "Satanism" and "moral decay" can be attributed to evolution and which can be attributed to other scientific models such as the general theory of relativity and gravity, the molecular theory of chemistry, or quantum nuclear physics.
The conclusion is inescapable; the creationist movement, knowing that it would be illegal to force their religious viewpoints onto others through legislation, instead made a deliberate effort to hide their religious goals so as to not have their law declared unconstitutional. Now that their legislative effort has fallen flat on its face, the need for the pretense of "science" is removed, and they can once again revert to their openly religious dogma.
In conclusion, then, by their own admission, the outlook of the creation "scientists" is not in any way, shape or form scientific. It is nothing more than a cynical and deliberate attempt to enshrine their own religious dogma into law under the guise of "science", in direct violation of the US Constitution and of all the basic principles of democracy.