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Evolutionary science and creationism: A skeptical response to Duane Gish’s “Creation Scientists Answer Their Critics” | Digital Bits Skeptic

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Evolutionary science and creationism: A skeptical response to Duane Gish’s “Creation Scientists Answer Their Critics”

2008 November 2

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By Matthew Green
Article ID: 1258

Controversy over creation and evolution persists. For most secularists, the battle was won long ago. It began with the publication of Darwin’s Origin of Species and the ensuing debates between Darwin’s defenders and his opponents. Creationism persists today for a simple reason: fundamentalism persists today. Creationism is nothing more than Christian apologetics attempting to validate the historical inerrancy of the creation accounts of the Hebrew Bible’s Book of Genesis. Creation “scientists” such as the late Henry Morris, Duane Gish, Jonathan Sarfati, and others use whatever “facts” to support Genesis, while rationalizing away anything to the contrary as a result of sloppy thinking or dishonest ulterior motives. They say that skeptics have more to do with “misotheism” (hatred of gods) or “compromise” than with honest scientific objectivity. These creationists believe that skepticism or disbelief is more from a desire to avoid a “relationship” with Jesus Christ and an existential involvement with the gospel. These pathetic attempts to construct a “science” out of creationism are attempts to present Christianity as intellectually respectable to the modern world. This ensures that the gospel isn’t dismissed out of hand by a more educated public. What it all comes down to is evangelism. Apologists are doing what they can to make the Bible look scientifically inerrant so they can have an easier time convincing people to become Christians.

This article shows that:

1) Creationists use Karl Popper’s universally accepted concept of “falsifiability” as a valid criterion for what constitutes a scientific theory.

2) Creationists do not seem to realize that evolution meets this criterion.

3) Creationists cannot pass this criterion on theological grounds because it is inconsistent with the nature of the Christian God.

Karl Popper’s criterion of “falsifiability”

Karl Popper was a science philosopher who proposed the criterion of “falsifiability” as a necessary ingredient of science. Falsifiability means that that an assertion can be proven false by observation or experiment.

This is the biggest criterion used to demarcate authentic science from pseudoscience. The Stanford Encyclopedia of Philosophy says this about Popper’s criterion of “falsifiability”:

“It is easy, [Popper] argues, to obtain evidence in favour of virtually any theory, and he consequently holds that such ‘corroboration’ … should count scientifically only if it is the positive result of a … prediction, which might conceivably have been false. For Popper, a theory is scientific only if it is refutable… Every genuine test of a scientific theory, then, is logically an attempt to refute or to falsify it, and one genuine counter-instance falsifies the whole theory. …In a word, an exception, far from ‘proving’ a rule, conclusively refutes it.

Every genuine scientific theory then, in Popper’s view, is prohibitive, in the sense that it forbids … particular events or occurrences. As such it can be tested and falsified, but never logically verified. Thus Popper stresses that it should not be inferred from the fact that a theory has withstood [testing and has been verified]; rather we should recognize that such a theory has received a high measure of corroboration and [is] the best available theory until it is finally falsified … or is superseded by a better theory.”

So the hallmark of a genuine scientific theory is “falsifiability”. It has to be capable of being refuted or falsified in order to truly qualify as a scientific theory. A theory is scientific only if it is refutable. This can be an observation, an experiment, or any other empirical test that can decisively refute it. Theories cannot be verified but they can be refuted and the failure of experiments, observations, or any other empirical test gives scientists greater confidence that the hypothesis or theory is, in fact, true.

Creationists accept this criterion as well. But they do so at a fatal cost.

Creationists accept Popper’s criterion of “falsifiability”

Creationists accept Popper’s criterion of “falsifiability”. A particularly excellent example of a creationist book which accepts falsifiability is Duane Gish’s Creation Scientists Answer Their Critics. Here Gish describes how he considers science. He writes on page 32:

“What is science? Loosely defined, one could say that science is what a scientist is doing when he is thinking. Of course, science, properly defined, would exclude much of the thinking done by scientists. Strictly defined, empirical science is our attempt to observe, understand, and explain events, processes, and properties that are repeatedly observable. On the basis of such theories predictions can be made concerning related natural phenomena or future natural events. Thus, experiments can be conceived and performed to test the theory and which may possibly show that the theory is wrong, if it is wrong. This property of potential falsification is an important element of a true scientific theory.”

Thus Gish accepts Popper’s criterion of falsifiability. But Gish feels that it’s necessary to distinguish between “operational science” and “historical science”. Gish writes on pages 32-33:

“Theories about origins, whether creation or evolution theories, are of necessity basically very different from empirical scientific theories. There were no human witnesses to the origin of the universe, to the origin of life, to the origin of a single living thing. These events were unique, unrepeatable, historical events which happened in the past. No one has ever seen a worm, a fish, or a man created. Neither has anyone ever seen a fish evolve into an amphibian or an ape evolve into a man. Furthermore, one cannot go into the laboratory and test a theory on how a fish might have evolved into an amphibian or how an ape might have evolved into a man. Creation and evolution are inferences based upon circumstantial evidence. They are attempts to explain events which have taken place in the past. Evolution theories do attempt to employ processes still acting today to explain how evolution may have occurred, but the time spans required to see if such ideas are correct involve tens of thousands of years, even millions of years, so no test of the theories is possible.”

On pages 34-35, Gish says:

“…it seems difficult, if not impossible to conceive of an observation or an experiment that could ultimately falsify the general concept of special creation. The details of the general concept can always be modified to accommodate new facts. We hasten to add that precisely the same can be said to be true of the general model … of evolution.”

Gish feels the need to call both creation and evolution “models” and feels that because of evolution’s time scale, it isn’t science. Yet Gish feels that both are testable, at least indirectly. It’s impossible to test the general concepts of creation and evolution directly, but each do have subsidiary hypotheses which can be tested directly. Gish fully accepts falsifiability as a criterion of science. Gish even seems to accept that creationism is scientific. He writes:

“Creation scientists maintain that modern science does enhance Genesis 1 by providing positive supporting physical evidence for creation.” (Page 230)

“One of the most important criteria of a scientific theory is the ability, on the basis of the theory, to predict the results of experimental tests, or what may occur in the future.” (Page 232)

So Gish accepts that falsifiability is a criterion of science and thinks that science supports the creation stories of Genesis by providing physical evidence for creation. But is Gish right? Is creationism a scientific concept even if it cannot be empirically tested? The answer is a resounding no.

Evolution is Fully Scientific

Our biological theory of evolution is fully scientific. Gish thinks that because evolution involves vast time scales, it cannot be tested and isn’t directly scientific. This is false. Scientific theories are both predictive and retrodictive. Scientific theories make predictions about what will occur in the future. They also make retrodictions, or what we should infer about the present if something happened in the past. Evolution is a scientific theory because it makes both predictions and retrodictions. Evolution’s grand prediction is explained by paleontologist Niles Eldredge. In his excellent book The Triumph of Evolution: and the Failure of Creationism, Eldredge discusses the scientific nature of evolution and its predictive power. He writes:

“Creationists are fond of pointing to the obvious fact that events that happened in the past are not subject to experimental verification or falsification, or to direct observation. After all, goes the creationist cry, no one was there at the beginning of the Cambrian Period to witness firsthand the supposed initial burst of evolutionary activity leading to the rapid evolution of complex animal life. How can we study something scientifically that has already happened? Creationists also note that few reputable biologists seem willing to predict what will happen next in evolution. And after all, says the creationist, if evolution is truly a scientific theory, it must be predictive- in the narrow sense of “making statements about what the future will hold”… According to this creationist interpretation of science, that biologists neither can nor will predict the evolutionary future is strong evidence that the very idea of evolution isn’t really scientific at all.

All this fancy rhetoric beclouds the simple meaning of ‘predictivity’ in science. All that ‘predictivity’ really means is that if an idea is true, there should be certain consequences-certain phenomena that we would expect – predict - to find if we looked. We should be able to go to nature-to the physical, material world – to see whether or not these predicted phenomena are really there. So in this spirit, we simply ask, if the basic idea is correct that all organisms past and present are interrelated by a process of ancestry and descent that we call evolution, what should we expect to find in the real world as a consequence? These observable consequences are the predictions we should be making – not guesses about the future.

Prediction 1: The very idea of evolution – descent with modification – implies that some species are more closely related to each other than they are to more distant relatives. Therefore, we would predict that the living world is organized into groupings of closely similar species that are in turn parts of larger groups of more distant relatives that share fewer similarities, that are in turn parts of still larger groups with definite, if fewer, similarities. Eventually, the largest grouping of all – all of life - should be united by the shared possession of one or more characteristics. In other words, if evolution is true, the living world should be organized in a hierarchical fashion of groups within groups – a direct reflection of how closely related to one another each organism is.” (Pages 25-26)

So, according to Eldredge, living organisms can be arranged into groups within groups within groups, until all of life can be organized hierarchically into one major group, with subgroups and subgroups, down to the species level and lower. Eldredge is right that this is a prediction of evolution but he could’ve gone further. A hierarchical grouping of organisms forms a nested hierarchy and a nested hierarchy is exactly what evolution predicts. This is not just a prediction of evolution but it’s also a retrodiction of evolution. If evolution happened in history, then a nested hierarchy is what we should expect to observe in the present. This is evolution’s grand retrodiction. If evolution is happening now, then we should expect to observe a nested hierarchy in the future.

Eldredge continues with his discussion of the predictive nature of evolution:

“In a very real sense, this prediction was discovered to hold true long before the idea of evolution was commonly accepted as the explanation for how the living world is organized. For at least a century before Charles Darwin (1809-1882) published On the Origin of Species by Means of Natural Selection, in 1859, biologists had recognized that life is organized into distinct groupings arranged in a natural, hierarchical fashion. The famous Swedish naturalist Carl von Linne (1707-1778) – more familiarly known simply as Linnaeus – established a natural system, before the idea of evolution had been generally accepted. (Linnaeus, like most other biologists before Darwin, was himself a creationist). Linnaeus saw natural groupings of different kinds of plants within his Kingdom Plantae, and of different kinds of animals within his Kingdom Animalia. Biologists since Linnaeus’ time have greatly refined his work, cataloguing hundreds of thousands of additional species and adding to the categories of Linnaeus’s original classification scheme, but the basic hierarchical structure of Linnaeus’s scheme remains, as it is simply a reflection of how biological nature is organized. Darwin came along and simply showed why the Linnean hierarchy exists- why it must be there if life has evolved. The Linnaean hierarchy, even though its rudiments were recognized almost a century before Darwin’s epochal book, is a necessary consequence – a prediction - of what the structure of the living world must look like if all of life has descended from a single common ancestor.

Let’s look at this prediction from a different perspective-literally from the bottom up: Because there are a lot of differences between, say, bacteria, pine trees, rats, and humans, if evolution has actually happened, it must be the case that as new species arose from old, changes in the genetic, anatomical, and behavioral properties or organisms appeared from time to time. Later descendents would inherit these changes, while ancestors (whether survivors to the present, or found as fossils) would, of course, lack these new features. Because there are millions of species on the planet, we know that if evolution has occurred, there must be a process of lineage splitting – diversification – going on. There more recent the evolutionary diversification, the more similarities ought to be shared by organisms.” (Pages 26-27)

Elredge acknowledges that the Linnaean hierarchy existed before Darwin’s time, but Darwin explained why the hierarchy exists. But Elredge can go further though and argue that evolution both predicts and retrodicts a nested hierarchy. If evolution happened in the course of earth history, then a nested hierarchy of living organisms is what we should expect to see as a consequence today. If evolution is happening right now, then a nested hierarchy is what we should expect to observe in the future. If we could travel to the past, say, to the Cambrian period, and observe the living organisms present as well as the processes underlying evolutionary change, we could make a prediction about what scientists would be able to observe in the 21st century: a nested hierarchy. Living as we do in the 21st century, a nested hierarchy is exactly what we do find. And when evolution happens today, a nested hierarchy – changed because of the evolution of new species – will exist in the future. Scientists will be able to observe and categorize all living organisms into one hierarchy.

Another book by Elredge, The Triumph of Evolution: and the Failure of Creationism is an updated version of his earlier book The Monkey Business: A Scientist looks at Creationism.

Duane Gish, in his book Creation Scientists Answer Their Critics makes a weak attempt to answer Elredge. Gish writes:

“The history of biology, however, flatly contradicts Elredge’s story. The fact that living organisms can be arranged into a hierarchy consisting of nested groups was known long before the time of Darwin, long before his theory of evolution had been spawned. The modern system of taxonomy, which groups organisms into species, genera, families, orders, classes, and phyla, was devised by Carolus Linnaeus, whose work preceded the publication of Darwin’s Origin of Species by 100 years. How can one say that this was a prediction of evolutionary theory, when it was commonly known 100 years before Darwinism burst upon the scene?” (Page 234)

Gish doesn’t realize that most scientific theories make both predictions and retrodictions. Just because the nested hierarchy was discovered a century or so before Darwin’s publication of The Origin doesn’t mean that a nested hierarchy is not a consequence of evolution. Consider for instance the theory of “plate tectonics“. Plate tectonics was proposed as a theory about how to explain why the continents move. That the continents once fitted together was proposed as a serious theory by Alfred Wegener in 1915 with his publication of The Origins of Continents and Oceans.

The notion of a jigsaw-puzzle-like fit of all the continents had been noted before Wegener but Wegener was the first to provide observations and arguments in favor of this fit of the continents and their subsequent separation. Wegener documented significant climatological and fossil evidence in favor of the concept. But scientists didn’t take his theory seriously because Wegener had not proposed a plausible mechanism for why “continental drift” was supposed to have occurred. It wasn’t until decades later that a scientific mechanism was proposed by Harry Hess, that of seafloor spreading. The Atlantic Ocean, it was proposed, is expanding and the Pacific Ocean is shrinking. Old oceanic crust is consumed in the trenches; new magma rises and cools off to form new crust. This theory of plate tectonics makes both predictions and retrodictions. It makes the retrodiction that all of the continents were once fitted together like a jigsaw puzzle. It makes the retrodiction that in the past, the Atlantic Ocean was smaller and the Pacific Ocean was bigger. It makes the prediction that continents are moving apart, the Atlantic Ocean is expanding outward, and the Pacific Ocean’s area is shrinking.

Gish’s argument that the classification hierarchy does not support the notion of evolution is like arguing that because Alfred Wegener and others before him proposed that the continents fit together in a jigsaw puzzle-like fashion, then this provides no support for the modern theory of plate tectonics. Scientific theories both predict and retrodict; plate tectonics retrodicts the jigsaw puzzle-like fit of the continents and evolution retrodicts the existence of a hierarchical grouping of living organisms. Plate tectonics predicts that the seafloor spreading will continue, the Atlantic Ocean’s size will expand and the Pacific Ocean will shrink. Likewise, as evolution continues, it predicts that new species will evolve, other species will go extinct, and the nested hierarchy will change over time.

Another example comes to mind of a scientific theory that both predicts and retrodicts: atomic theory. Modern atomic theory is informed by quantum mechanics, studies in radioactive decay, and other experiments on the nature of light. All of modern chemistry is based upon modern atomic theory. In chemistry, we learn about two kinds of compounds: ionic and molecular. Ionic compounds such as sodium chloride have an ionic chemical bond between the two elements. Molecular compounds (like water) have covalent chemical bonds. Modern atomic theory both predicts and retrodicts that water will always have the same chemical formula, H2O. All water found in earth’s history and in the far reaches of space will all have this chemical formula, and the chemical bonds between the oxygen and hydrogen atoms will always be a covalent chemical bond. As long as water existed in the past, modern atomic theory retrodicts that all molecules of water have involved covalent chemical bonds between one oxygen and two hydrogen atoms. The existence of liquid water in the future will always have covalent chemical bonds between one oxygen atom and two hydrogen atoms. Scientific theories like modern atomic theories, plate tectonics, and evolution all make predictions and retrodictions.

Creationists are wrong to try to separate “empirical” science from “origins” science. Modern scientists see no reason to make such a distinction. Making creationism and evolution methodologically equivalent is a dishonest ploy by creationists. If evolution is scientific, they argue, then so is creationism. If creationism is unscientific, then so is evolution. But this ignores a key fact: creationism, while making “retrodictions”, does not make predictions. Assume a creator does exist and has acted in the past by creating life forms. This creator has a will and isn’t a slave to any law that says that it must periodically create new life forms. Nor are such acts observable by any scientific means. Creationism doesn’t predict, for example, a new living organism will be created at a given time in the future. A creator isn’t bound to any repeatable and predictable action. No creator’s action can be found upon which scientists can observe, measure, and perform experiments.

Creationism fails on another ground. Whether as “operational science” or as “origins science”, arguing that creationism is falsifiable in any sense is to pose a serious theological problem from which creationists cannot escape.

Falsifiability and the problem of God’s honesty

Most creationists are Christians of one stripe or another. As Christians, particularly fundamentalists, they believe that the Bible is the inerrant, inspired word of God. They believe that God is perfect and cannot err. God is a morally perfect and morally necessary being. God, according to the Bible, cannot do anything wrong. If God could do wrong but simply chooses not to, God would be a morally contingent being like us. Human beings are “morally contingent” or “morally imperfect” beings: we can do wrong if we so choose. God cannot do wrong even if he wanted to. Christians argue that he cannot even desire to do wrong. This definitely has support from the Bible. There are numerous passages in the Bible which lend support to this view of God as morally perfect and necessary. Consider, for instance, Hebrews 6:18:

“God did this so that, by two unchangeable things in which it is impossible for God to lie, we who have fled to take hold of the hope offered to us may be greatly encouraged.”

The New Testament epistle of James 1:13 says the following:

“When tempted, no one should say ‘God is tempting me.’ For God cannot be tempted by evil, nor does he tempt anyone.”

These two passages lend support to the concept of moral perfection or moral necessity. Moral perfection and necessity is a required attribute of God. God cannot lie. God cannot be tempted. It’s not the case that God could be tempted to do evil but simply resists the temptation. No, it’s impossible for God to lie, impossible for him to be tempted by evil to do evil. It’s impossible for him to do anything wrong. This is because God is a morally perfect being. Christians gladly agree with the following but may have trouble understanding the problem this poses for trying to make creationism scientific in any sense. The reason should be obvious by now: if God says he created the heavens and earth in six days (Exodus 20:11), then it is true. It cannot be false. So if Exodus 20:11 affirms that the Genesis story is meant to be taken literally, then to suggest that creationism is scientific is to suggest that creationism can be falsified. If creationism can be tested and is capable of being refuted, this suggests that creationism is only probably true, not necessarily true. To suggest that creationism (and the Genesis creation story) is capable of being tested and refuted by science is to suggest that it’s possible that God lied. If creationism can be tested scientifically in any sense is to suggest that creation is possibly false but in all likelihood true. By trying to subject the creation stories of Genesis to scientific testing (and making them potentially falsifiable), creation “science” makes it possible for the Christian God to be a liar. According to Hebrews 6:18, it is impossible for God to lie. So which is it? Is it impossible for God to lie, thereby making creationism unscientific on theological grounds, or do creationists make creationism “scientific”, thereby refuting the theological truth that their God is morally perfect? In other words, if creationism is scientific, then Hebrews 6:18 is in error, the Bible is not the inspired word of God, and the Christian God as popularly defined doesn’t exist.


Evolution is a scientific theory. Scientific theories depend on Karl Popper’s criterion of falsifiability to qualify. As quotes from Duane Gish’s book demonstrate, even creationists accept this. Scientific theories such as the theory of evolution, the theory of plate tectonics, and modern atomic theory are both predictive and retrodictive. Evolution both predicts and retrodicts a nested hierarchy and the predictions and retrodictions will be observed. Creationists like Gish argue that origin theories are not empirically scientific but are capable of being falsified. Empirical scientific theories are directly falsifiable because they make predictions.

But making creationism scientific runs into seriously fatal theological problems. New Testament verses like Hebrews 6:18 lend support to God being a morally necessary being. God cannot lie. It’s not the case that God could lie if he wanted to but simply chooses not to; no, God cannot lie being a morally perfect being. This runs into problems with trying to make creationism sound scientific as making creationism scientific in any way refutes the notion that God cannot lie and is morally necessary. But if God is a morally perfect being and told the truth in Exodus 20:11, then the creation story of Genesis one is a necessary truth and cannot be false, and cannot be falsified. To be subjected to scientific testing is to suggest that it can be falsified. If creationism is scientific, then creationism, contrary to biblical doctrines about God, is capable of being false and it’s perfectly possible that God lied but probably told the truth because it’s possible that creationism is false but in all likelihood true. If creationism is scientific, then that refutes the moral perfection of God, and therefore the Bible cannot be inspired, and therefore the Christian God doesn’t exist.

Evolution wins not just because the evidence supports it, but because the attempt to make creationism look “scientific” is a tactic that backfires on creationists who use it.

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2008 November 2
Immanuel Zorg permalink

I like the “broken logic” loop. That’s a new concept to me.

2008 November 6
Sandra H permalink

Great article! It took a tact I hadn’t heard of before – that god is lying. You just can’t beat that horse dead enough for creationists.

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