Creationists and Evolutionary Theory
...............................................Rob Bass

[What follows was originally written as a result of conversations with a young-earth creationist.¹ Among other things, he loaned me a creationist book by Howard Peth – which was neither especially good nor especially bad as such things go. In any event, that prompted the current essay on some of the ways that creationists misunderstand evolution and evolutionary theory.² I will refer to Peth’s book,³ but since I don’t have a copy at hand, I can’t give page references.]

1. What is the theory of evolution?

There are three things to be distinguished – whether evolution has occurred, what its principal mechanisms are, and what has actually occurred in the history of life on this planet. The claim that evolution has occurred is a theory about organic change through time. Emphasize that word change. The claim that evolution has occurred is not, by itself, a claim about the direction – toward greater complexity, for example – of evolutionary change. There can be, for example, evolutionary change that makes descendants simpler than the ancestral stock from which they derived. Whether there are overall trends toward greater complexity and how, if there are, those trends are to be explained, are further questions.

To say that evolution has occurred means that current organisms are descended from ancestral forms that are not necessarily of the same species as themselves. Thus, humans can be descended from non-humans, wolves from non-wolves, cabbages from non-cabbages and so on. In principle, if this is true, there only needs to have been one ultimate ancestral kind of organism for every other current or past organism to have been descended from. There might have been more than one kind of ultimately ancestral organism, but the theory does not require it. Note that this is not a religious or antireligious view per se. It says nothing about whether God created the ultimate ancestors or intervened along the way to guide the evolutionary process. Many evolutionists believe that there was no need for divine intervention at any point, either to get the process going or to guide it once it was underway, but believing that there have been no interventions is not part of what is meant by believing that evolution has occurred. (There are also many evolutionists, in this sense of the word, who do think God started things off or intervened along the way.)

If we limit the question to whether evolution has occurred in the above sense, that it has indeed occurred is as well established as anything in science. If the evidence we have for it is not good enough for it to count as knowledge, then nothing else in science should count either. That includes things creationists like to appeal to, such as the second law of thermodynamics (which they misunderstand). By any reasonable standards, it is a fact that evolution has occurred.⁴ If nonetheless the Genesis account of creation is literally true, just about the only way to interpret that is to say that, though Genesis is true and evolution is not, God wantsus to believe in evolution since that’s what the evidence supports. Or else, he wants us to be unreasonable!

Now, I can be much briefer about the second issue. Once the fact of evolution is admitted, we can ask about its mechanisms – about how it occurred. Darwinism is a theory about the principal mechanism of adaptive change in evolution – specifically, about what accounts for the emergence of complex and apparently well-designed order. The Darwinian thesis is that the central or driving force of such evolutionary change is natural selection operating upon variants produced mainly through mutation. That natural selection plays a role in evolution is nearly as certain as that evolution has occurred at all. What is still open for debate among evolutionary theorists is how important that role is in comparison with other possible mechanisms and what those other possible mechanisms are. No serious theorist thinks that natural selection is literally the only mechanism of evolutionary change nor do any think that it has no role at all. The debates are about what mechanisms there are and what their relative importance is. A theorist can be an anti-Darwinist if he thinks that natural selection is not important in evolutionary change, that some other factor or combination of factors is as important or more important, but such a theorist is not therefore an anti-evolutionist. Most evolutionists cited by creationists as critical of evolutionary theory are in fact debating issues about mechanisms of evolutionary change. They are not questioning whether there has been evolutionary change at all. (Nor, in light of the evidence, could they be questioning whether evolutionary change has occurred.)

The third issue, also sometimes identified with evolutionary theory, has to do with the specific course of evolution on this planet – the order in which organisms appeared and what is descended from what. For this, our main, though not our only, source of evidence is the fossil record, interpreted in the light of our best theories about mechanisms of evolutionary change, our knowledge of the conditions necessary for fossilization, and our geological knowledge about how the layers were laid down and what forces they have been subjected to and what changes have occurred in or to them since they were laid down.

2.     Natural selection is really just an uninformative tautology.⁵ It says that the fittest survive, but then defines fitness in terms of survival so that the only test for fitness is whether or not an organism actually survives. What it comes down to is just saying that survivors survive.

This is a mistake, though it is one creationists have some excuse for, since some evolutionists have made it, too. To begin to show what’s wrong with it, let me point out something that should be obvious upon reflection. It’s possible that testing for the presence of one feature of a particular thing is the only way of testing for the presence of another feature without it being true that saying it has the first feature means the same as saying that it has the second feature. Here’s an example: It might be that the only way we have to test for whether a being has human-level intelligence is by finding out whether we can have (what we regard as) an intelligent conversation with it. That still wouldn’t show that “ability to participate in an intelligent conversation� is what we mean by human-level intelligence. We might not have a shared language to converse in. Or, going in the other direction, we might find out we were conversing with a cleverly programmed computer. In the same way, it might be that survival is the only test for fitness without being what we mean by fitness.

In fact, as evolutionists use the terms, it is not true either that survival means the same thing as fitness or that survival is the only test for fitness. So, what do evolutionists mean by survival of the fittest? Well, in the first place, it hardly matters because no serious evolutionist really does believe in some principle of survival of the fittest if that means survival only of the fittest. To get at what they really believe, a couple of modifications are needed. Start with “fittest.â€? What they really believe in is the survival of the fit enough, where an organism is fit enough relative to a given environment, including other organisms that are around in the same environment. They aren’t so silly as to believe that only a single kind of organism, the “fittest,â€? can survive. Second, they don’t literally mean survival in the sense of staying alive. What they mean is “survival at least to the age of successful reproduction.â€? A sterile cat, for example, might live twenty years, thereby doing a great job at surviving, but if it does not contribute to the existence of other cats in future generations carrying its genes,⁶ then it hasn’t survived in the sense evolutionists are interested in and its fitness is zero.⁷ So, what evolutionists really believe in, instead of “survival of the fittest,â€? is more like “survival to the age of successful reproduction or contribution to reproduction of organisms that are fit enough relative to the environments in which they live.â€? Of course, that doesn’t make a snappy slogan, but it’s what you should keep in mind when you hear about “survival of the fittest.â€?

Now, let’s take a closer look at what evolutionists mean by fitness. First, as I said, fitness is relative to an environment, including other organisms in that environment. There’s no such thing as “absolute fitness.� Since fitness is relative to an environment, the fitness of an organism can change either because of physical changes in the environment or because of changes in the distribution or population or presence of other organisms. Second, it refers to heritable traits of an organism. There may be other traits that make a difference to whether an organism reproduces that are acquired during its lifetime, such as learned skills. Similarly, there may be things other than traits of organisms, such as the effects of accident, that also make a difference to reproductive success. (Of two genetically identical organisms, for example, one gets struck by lightning and leaves no descendants. Since the two are genetically identical in the same environment, they are equally fit.) But since luck and learned skill are not transmitted through heredity (though the capacity for learning may be), they are not counted as part of an organism’s fitness. What the fitness of an organism is (relative to an environment) is not the set of properties that results in its actual survival and reproduction, but the set of heritable properties that tends to promote its survival and reproduction. This can be made more precise mathematically by representing an organism’s fitness in terms of what would be, for an organism carrying those genes in that environment, the expected number of offspring or relatives (or both) to which it would contribute. And, by the “expected number� is meant the average number that would be predicted for organisms of that type. (For example, a young American male who has not had any actual children may be expected to have, say, 2.1 children. That is, on the basis of all that is known about American males at present, that is the average number of offspring they have. It doesn’t mean that any particular American will have exactly that many [how could it?]; some will have more, some less.)

This is part of the explanation why survival of the fittest (or, better, successful reproduction of the fit enough) is not a tautology. Fitness refers to the heritable properties that tend to result in successful reproduction (and there are other tests for fitness, at least in some cases, than actual successful reproduction). But it is, of course, a statement about tendencies, not about what happens in every case. The other part of the explanation is that fitness refers to actual properties that organisms have. Evolutionists, when faced with an example, either past or contemporary, do not just say “well, it survived and reproduced; therefore, it ‘must’ be fit (or more fit).� They can offer specific, independently checkable explanations of why particular properties, like hollow bones in flying creatures, should have increased the likelihood that organisms with those features would tend to out-reproduce otherwise similar organisms without those features. In fact, it is because it is possible to independently check whether given traits promote fitness that evolutionists have had to admit that some evolutionary change is fitness-neutral, that sometimes traits can spread through a population without improving (or harming) the fitness of their bearers.

3.     Evolutionists are guilty of circular reasoning in dating fossils by the geological strata in which they turn up while dating the strata by the fossils they contain.

Nonsense. In the first place, it’s historically false. The geological time-table was worked out by creationist (!) geologists before the time of Darwin. The basic ordering and relative ages were settled by 1840 (about two decades before Origin of the Species in 1859). There’ve been changes in detail since then, but nothing to upset the basic structure.

The basic working assumption of the geologists who worked out the time-table – an assumption that is hardly questionable unless you think the law of gravity has changed in the earth’s history – is that lower or deeper strata were laid down before strata above them. It was fairly quickly realized that, in almost every case around the world, there was a characteristic ordering of the fossils the layers contained. Dinosaurs are never found buried in deeper layers than trilobites, and human remains are never found deeper than dinosaurs. Once this had been realized, then it was possible to use the presence of particular fossils in a deposit as a quick way of dating the strata in which they occurred. There’s no circularity here, just the use of one well-confirmed pattern of facts as an index to determine another fact of interest.

Above, I said “in almost every case around the world.� Are there exceptions to the characteristic order of the fossils? Yes, there are some (but none like dinosaurs being buried deeper than trilobites or people with the dinosaurs!). There are places where, judging by the fossils they contain, the strata appear to be out of order. There are not many. Compared to the number of locations where the fossils occur in the characteristic order, there are very few.

Still, exceptions are exceptions and cry out either for explanation or for rejection of the theory that fossil order is a reliable index to relative dating. Are evolutionists reduced to saying that the “misplaced� strata must be misplaced simply because otherwise, the fossil evidence would count against their theory? If they were, then they would be engaging in circular reasoning. But they are not. First, there are some tell-tale facts about the misplaced strata that strongly suggest that they really are misplaced. One is that when there is a sequence of strata that are not in the standard order, they almost always fit into one of two categories. Either a sequence of layers is doubled, suggesting that some geological event has split several strata and pushed some on top of others, or the strata occur in precisely the reverse of the characteristic order, suggesting that the strata in that region have been turned upside-down. What we do not find is strata that vary randomly from the characteristic order – which is what we should expect if the characteristic order of fossil organisms were not a reliable guide to relative dates. There are other clues. One that is frequently overlooked by creationists is that we can often tell, entirely apart from external geological evidence, that a layer is upside-down. Many things that leave fossil traces – footprints, for example – are recognizably different if they are upside-down. Beyond this, there is often external geological evidence of fault and over-thrust formations. This is true, for example, of the Lewis formation in Montana mentioned in Peth’s book. The fault is visible for, if I remember correctly, something like three miles. We would know that the strata there are displaced from their original order even if there were no fossils at all in the formation. (One has to wonder about the honesty of whoever originally cited this formation as a problem for the conventional dating of the strata and fossils it contains.) It is simply not true that evolutionists assume their theory to date the strata and assume the strata dates to determine the evolutionary sequence.

All of the above has been about relative dating – about what precedes and follows what. Can the evolutionist go beyond this to provide absolute dating? The answer to that is: of course! There are numerous dating techniques, many of them based on radioactive decay processes. Though they do not all coincide perfectly for the ranges of dates for which they are useful, there is enough overlapping that we know that they correspond nicely to one another and, where more than one can be employed, almost always give approximately the same dates for the samples to which they are applied. Moreover, these dates also match up with the relative dating established independently for the strata. Briefly, the earth is about four and a half billion years old, it has supported life for a very long time – at least 2.8 billion years – and biologically modern human beings are relative late-comers, showing up about a hundred thousand years ago. None of that is seriously questionable by anyone well-informed about the evidence, and creationists have given no reason to question it.⁸

4.     The second law of thermodynamics, which says that entropy, a measure of the disorder of physical systems, is increasing, is incompatible with the evolutionary development of more complex and therefore more highly ordered forms.

About all this objection shows is that creationists don’t understand what the second law says. Though he devotes a whole chapter to it, Peth never manages to state the law correctly even once. The main fact that he leaves out is that the second law only applies to closed systems.

The second law does not say that all physical systems decrease in order or that none ever increase. If it did, it would be self-evidently silly, since it would rule out well-known phenomena like plant or animal growth. It applies to closed systems with no external sources of energy. The earth, of course, is not a closed system, since, over four and a half billion years, it has been and continues to be bathed in radiation from the sun. The second law poses no bar to the increase in the complexity of organisms on earth over billions of years, since the earth has always had an external energy source.⁹

Creationists are apt to push the question, though, as to how the whole universe, which cosmologists usually take to be a closed and finite system, could “start outâ€? and why there is any available energy, from the sun or anywhere else, to make possible any increases in complexity anywhere. However, this is really beside the point. Whether God (or something else we don’t understand) was needed to get the universe going¹⁰ simply doesn’t bear on whether evolution and increasing complexity of life on earth is possible, given that the earth is an open system receiving a constant influx of energy from outside. Evolution of life on earth is entirely compatible with the second law.

5.     Evolutionary theory is not really science because science has to be based on observed phenomena and demonstrated fact, has to make predictions and be open to testing. But evolutionary theory talks about events in the past that no one was present to observe and makes no testable predictions.

This depends on a double misunderstanding: of science on the one hand and of the actual character of evolutionary theory on the other. Let’s begin with science. It’s true that science has to make contact with experience somehow, but the connection doesn’t have to be by direct observation. For example, we knew that the earth was round through a variety of indirect tests long before the time, during this century, that people were able for the first time to get far enough away to directly observe its roundness. There were arguments from the fact that you could travel in a single direction and end up back where you started, from the shape of the earth’s shadow on the moon, from the way that approaching and departing ships looked as they crossed the horizon and so on. The general pattern of such arguments is: If such-and-such a theory is true, then we should expect to observe thus-and-so, unless there is some interfering factor. If we find what we expect, that confirms the theory; if we don’t, that counts against the theory.¹¹

To make this clearer, though, we need to pay special attention to the “unless� clause. The important thing about it is that we need ways of checking whether there is some interfering factor that don’t depend on the very theory we’re examining. We can, for example, use observations through telescopes to test theories about the shapes of planetary orbits because we have independent ways of checking the reliability of telescopes. Our theories about the laws of optics, and therefore about how telescopes work, do not assume anything about the shapes of planetary orbits. If someone held a theory about planetary orbits which he refused to revise in the face of contrary telescopic evidence, but offered no other reason for questioning the reliability of that evidence than that it did not conform to his theory, then he would just have been insulating the theory from any kind of test.

There’s nothing wrong with theoretical arguments in science that talk about what we do not directly observe. In fact, science is full of such things – talk of atoms and molecular structure, theories about the shape of the world or the solar system and so on. What’s important is that it be possible in principle to test, whether directly or not, the claims we make.

Of course, evolutionary theory has been subjected to numerous tests and it is possible to imagine any number of discoveries – like unquestionably human remains in the Devonian – that would completely upset the theory. But the theory has invariably passed the tests: The upsetting discoveries have not been made. The discoveries that have been made are of just the sort we would expect if the evolutionary theory is true.

6.     The fossil record actually counts against evolutionary theory because there are no (or very few) transitional forms between different species of the kind that would be expected on a Darwinian theory.

This goes wrong in at least three ways. First, it confuses Darwinism, a theory about the principal mechanism of evolutionary change, with evolutionary theory as a whole. If it were true that Darwinian assumptions should lead us to expect more transitional forms than are actually found in the fossil record, that would be a reason for giving up Darwinism, not a reason for giving up evolution.

Second, the objection is based only on ignorance of what the fossil record actually shows. In fact, there are hundreds or thousands of cases of transitional forms in the record. Of course, we would like to have more, but there isn’t such a shortage that it provides any reason for rejecting the basic Darwinian picture – though it is likely (which practically everyone admits) that natural selection is not the only important factor in evolutionary change.

Third, there is probably a mistake in logic behind the objection. Suppose you have two distinct organisms in the fossil record, one of which appears to be descended from the other. Creationsts say, “look, these are obviously different forms – if this is really a case of evolutionary change, where’s the transitional form between them?� Now suppose we do find an intermediate form in appropriate strata. The intermediate will have to be recognizably different from both of the others (else, we wouldn’t know it was an intermediate). Now, the creationists can say “look, this alleged intermediate is different from both the others – where are the transitional forms leading up to it and leading on to the next one?� In other words, if there is anything recognizably distinct at all between two forms, the discovery of an intermediate between the two will leave us with two gaps instead of one. This is a bizarre approach to interpreting the available evidence, amounting to treating good evidence that evolution and evolutionary transition has occurred as further evidence against. If that’s what the creationist is doing, then no fossil record could possibly be complete enough to satisfy him.

The fact is that we know of lots of transitional forms, but we don’t have enough – and never will have enough – to satisfy the unreasonable demands that creationists make. Evidence enough to satisfy any reasonable person who cares to investigate is readily available.¹² It’s not an objection to evolutionary theory that it can’t satisfy unreasonable demands.

7.     Massive fossil deposits appear for the first time in the Cambrian, with vast numbers of species showing up fully developed without any precursors. But the Cambrian layer is conventionally dated to only about 550 million years ago. The fossil record looks as though these organisms just showed up fully formed – as if they had been instantly created.

This is a half-truth exaggerated into a total falsehood. There certainly was a “Cambrian explosion.� The number and variety of different species vastly increased at that time. Why that happened then, rather than earlier or later or not at all is not well understood. However, it is not true that, as Peth says, there are no fossils “except a few alleged micro-organisms� in Pre-Cambrian strata. There are multi-cellular Pre-Cambrian fossils (including some trilobites, which were once thought to have appeared for the first time in the Cambrian layer). There are unquestioned, not merely alleged, fossils of micro-organisms going back to about 2.8 billion years ago (cyanobacteria in South Africa), and there are disputed fossils of micro-organisms as far back as the Isua (Greenland) microspores of about 3.7 billion years ago.

8.     What about “Flood geologyâ€? as an explanation of the geological record? Can’t a better explanation of the evidence be provided in terms of a single global catastrophe?

Not by a long shot. “Flood geologyâ€? is an ad hoc theory that is not remotely adequate to explain major features of the fossil record. Now, it should be admitted that there is evidence in particular cases of sudden, violent and rapid events of strata-deposition by, e.g., local floods, volcanic eruption and the like. Such evidence is not in the least incompatible with the uniformitarian assumptions upon which geologists typically rely. But there is no reason whatsoever for thinking that the overall character of the geological record can be well-explained by a single global catastrophe. Quoting Stephen Jay Gould:¹³

Creationists do offer some testable statements, and these are amenable to scientific analysis. Why, then, do I continue to claim that creationism is not science? Simply because these relatively few statements have been tested and conclusively refuted. Dogmatic assent to disproved claims is not scientific behavior ....

In “flood geology,� we find our richest source of testable creationist claims. Creationists have been forced into this uncharacteristically vulnerable stance by a troubling fact too well known to be denied: namely, that the geological record of fossils follows a single, invariant order throughout the world. The oldest rocks contain only single-celled creatures; invertebrates dominate later strata, followed by the first fishes, then dinosaurs, and finally large mammals ....

Since God created with such alacrity, all creatures once must have lived simultaneously on the earth. How, then, did their fossil remains get sorted into an invariable order in the earth’s strata? To resolve this particularly knotty problem, creationists invoke Noah’s flood: all creatures were churned together in the great flood and their fossilized succession reflects the order of their settling as the waters receded. But what natural processes would produce such a predictable order from a singular chaos? The testable proposals of “flood geology� have been advanced to explain the causes of this sorting.

Whitcomb and Morris offer three suggestions: The first – hydrological – holds that denser and more streamlined objects would have descended more rapidly and should populate the bottom strata (in conventional geology, the oldest strata). The second – ecological – envisions a sorting responsive to environment. Denizens of the ocean bottom were overcome by the flood waters first, and should lie in the lower strata; inhabitants of mountaintops postponed their inevitable demise, and now adorn our upper strata. The third – anatomical or functional – argues that certain animals, by their high intelligence or superior mobility, might have struggled successfully for a time, and ended up at the top.

All three proposals have been proven false. The lower strata abound in delicate, floating creatures, as well as spherical globs. Many oceanic creatures – whales and teleost fishes in particular – appear only in upper strata, well above hordes of terrestrial forms. Clumsy sloths (not to mention hundreds of species of marine invertebrates) are restricted to strata lying well above others that serve as exclusive homes for scores of lithe and nimble small dinosaurs and pterosaurs.

The very invariance of the universal fossil sequence is the strongest argument against its production in a single gulp. Could exceptionless order possibly arise from a contemporaneous mixture by such dubious processes of sorting? Surely, somewhere, at least one courageous trilobite would have paddled on valiantly (as its colleagues succumbed) and won a place in the upper strata. Surely, on some primordial beach, a man would have suffered a heart attack and been washed into the lower strata before intelligence had a chance to plot a temporary escape. But if the strata represent vast stretches of sequential time, then the invariant order is an expectation, not a problem. No trilobite lies in the upper strata because they all perished 225 million years ago. No man keeps lithified company with a dinosaur, because we were still 60 million years in the future when the last dinosaur perished.

9.     What about those scary probability calculations?

Creationist works are replete with probability estimates that purport to show that there are extremely long odds against the right events occurring together by chance to (take your pick) create life, produce DNA, manufacture proteins, account for the development of a particular organ such as the human eye, or account for the development of a species from a supposed ancestor to a significantly different descendant.

Almost invariably, though, there is a simple mistake in the probability calculations.¹⁴ Let me illustrate it this way: Suppose you’re going to get a prize if you get each of ten guesses correct and you have a one in twenty-six chance for each one. A simple calculation¹⁵ shows your chance of getting them all right is about one in 140 trillion. In other words, if you made one guess a second, it would take close to four and a half million years. Absurd. For all practical purposes, you haven’t got a chance.

But wait! It may have occurred to you that the guessing game I was describing was the kind you see on television programs like “Wheel of Fortune.� A contestant is asked to guess what a concealed word or phrase is. For each letter, he has a one in twenty-six chance of getting it right. But the shows don’t go on for millions of years and the contestants often do succeed in guessing the words. How is that possible? Didn’t we just prove that there was next to no chance of that happening? How is it that it not only happens, but happens over and over, show after show?

Part of the answer relates to what contestants know, such as the facts that the letters have to spell out something that can be pronounced, that it has to be in English, etc. But that’s not the most important part of the answer. Even a completely random guessing process would probably come up with the right answer within a few hundred guesses,¹⁶ instead of the trillions upon trillions that were calculated above. Why is that? Because the 140-trillion-to-one probability calculation represents the chance of getting all the steps right at once. But the guessing game is actually one that lets the contestant, even a completely random guesser, keep successes and throw away failures. Once a letter has been gotten right, it remains and the guessing proceeds to trying to get some other letter right, which is kept in its turn, and so on. This is, in principle, the same way that natural selection works: It keeps successes and throws away failures. Organisms that do better at surviving and reproducing are represented in the next generation and have another shot at being improved. Those that are not as good at surviving and reproducing get eliminated. The problem that actually has to be faced in figuring out how natural processes could produce something complicated through many steps is not the one that creationists are calculating the probability of solving. It may be practically impossible to solve the problem the creationists pose – how to get lots of steps right all at once – but that isn’t the problem that nature had to solve. The problem that nature did have to solve is not nearly so difficult. All that’s needed to solve the real problem is a process, natural selection, that keeps successes and throws away failures, a source of change, such as mutations, that can make a difference to success or failure, and enough time to let it work. The evidence is that all of those conditions are satisfied.

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