A Critique of Evolution | Part 2

The Science of Evolution

This series sets out to demonstrate why the fact that evolution is the accepted scientific explanation of the origin of the species does not necessarily entail that evolution was the true origin of the species, nor that we should feel confident in assuming that it was.

In Part I, we explored why science must assume naturalism in order to function, but its core purpose is utility rather than truth.

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If there are some theories of science that we might all feel very comfortable accepting as ‘truth’ despite this reality, should the theory of evolution be one of them?

Let us allow, then, that we do not know scientific knowledge to be true, but only that it is useful in modeling the true causes of things in a way that allows us to understand, replicate, and predict certain phenomena. If the model does all of these things very well, then we have good reason to think the model may be very much like the truth, but if certain phenomena defy the expectations of the model—even if the model fares fairly well in its explanation of other phenomena—then our model needs to be revised, and in the end, we ought to recognize that the true model may wind up making radically different assumptions about the nature of the universe than the one we currently have. So how well does the evolutionary theory fare when judged by these criteria? Does it really do just as well as the theory of relativity, or quantum mechanics, or rocket science, such that we have no reason to accept the assumptions made by all these if we would simultaneously deny those made by the theory of evolution?

Well, yes and no. In the sense that evolution has a great deal of explanatory power, and that it is the best naturalistic account of the origin of life to date, yes, it is as good as other theories. It can explain, for example, the apparent similarities between plants and animals belonging to the same genus, order, phylum, and class, and why it is that organisms differ according to their environments. It explains why we share DNA with monkeys, and why DNA is shared by all living things. It explains how populations of bacteria develop resistance to antibiotics, and—to a certain extent—the historical progression of different life forms appearing in the fossil record. It also explains the violence, the waste, and the chaos that is often apparent in the animal kingdom.

However, in certain key respects, the evolutionary theory remains lacking as a model of the origin of the species. To begin with, the most critical steps of the process—how even the simplest form of life might have been generated from non-living material, and how any type of living creature might, through the accumulation of small, random mutations over time, eventually evolve into a quite different type of creature—have not, and indeed perhaps cannot, be replicated. Yet, these kinds of evolution theoretically occurred over millions and millions of years, and we have only been trying to replicate them for a few hundred—so the replication failure is perhaps not so troublesome in itself, especially given that we can replicate intraspecies adaptation, at least, quite well.

But then, we might justly turn to the question, how accurate have the predictions generated by evolutionary theorists turned out to be?

One must turn to the fossil record in search of evidence for the hypothesis that all living creatures are the result of descendance with modification from a single common ancestor, given that we can see species changing only very slightly in the present day. In Chapter Nine of The Origin of the Species, Darwin writes:

By the theory of natural selection all living species have been connected with the parent-species of each genus, by differences not greater than we see between the varieties of the same species at the present day; and these parent species, now generally extinct, have in their turn been similarly connected with more ancient species; and so on backwards, always converging to the common ancestor of each great class. So that the number of intermediate and transitional links, between all living and extinct species, must have been inconceivably great.

Now, Darwin was quite familiar with the fossil record as it existed in his day, and with the fact that most species appeared quite suddenly in the rocks and appeared to remain very much the same—sometimes for millions of years—before disappearing entirely on account of extinction. This reality had the leading paleontologists of the day believing quite firmly in the immutability of the species, and Darwin spends most of the chapter explaining why, if so many "intermediate and transitional links" between parent-species and their diverging offspring must have existed in the past, we don't find more series of fossils exhibiting gradual change from one species into another. He makes several strong arguments, about the vast imperfection of the fossil record, and the impossibility of recognizing one species as the ancestor of another if a few of the generations between the two failed to fossilize, so breaking the series of gradual change, and how a newly evolved species might replicate and migrate far before becoming fossilized and so seem to have exploded into existence all at once rather than having developed through the accumulation of small changes to the parent species. But, he admitted:

I do not pretend that I ever should have suspected how poor a record of the mutations of life, the best preserved geological section presented, had not the difficulty of our not discovering innumerable transitions between species which appeared at the commencement and close of each formation, pressed so hardly on my theory.

In other words, the fossil record, as it existed in his day, was not as compatible with his theory as he might have predicted, had he proposed his theory without already knowing and attempting to account for the problems posed for it by the fossil record.

But that was hundreds of years ago. We have uncovered a great many more fossils since then. Even if we grant that the fossil record remains staggeringly incomplete due to the unique conditions necessary for the creation of fossils, we might reasonably expect to have uncovered many more "intermediate and transitional links," as well as more series exhibiting gradual directional change if Darwin's theory were really true. Have we?

Well, yes and no. Yes, in the sense that we've uncovered many potential links between major groups of animals. Archaeopteryx exhibits some characteristics of both reptiles and birds, therapsids of both reptiles and mammals, ichtyostegids of both fish and amphibians. We have also uncovered some series of fossils that exhibit some small changes over time. But still, after all this time, and in the words of Stephen Jay Gould:

The historical record of most fossil species includes two features particularly inconsistent with gradualism:

1. Stasis. Most species exhibit no directional change during their tenure on earth. They appear in the fossil record looking much the same as when they disappear; morphological change is usually limited and directionless.

2. Sudden appearance. In any local area, a species does not arise gradually by the steady transformation of its ancestors; it appears all at once and ‘fully formed.’ (Gould, Stephen Jay. "The Episodic Nature of Evolutionary Change." The Panda's Thumb. New York: W. W. Norton & Co., 1980. 179-185. Print.)

Now, to be fair, it is specifically gradualism that Gould critiques in this essay, not the theory of evolution as a whole. He argues that the fossil record does not support Darwin's theory of "phyletic transformation," that is, of the gradual transformation of whole populations of species into new species. He and Niles Eldredge proposed a theory called "punctuated equilibrium" to explain another way new species might often have come into being: by the evolution of relatively small, isolated populations that spread back into the parent population after having diverged from it.

This is all well and good as a way of explaining the general lack of gradual change exhibited by the various species during their tenure in the fossil record, assuming that the broad strokes of evolutionary theory were true, but it is not really clear that the fossil record provides solid evidence for evolution, even if we imagine evolution happened in this way. The theory of punctuated equilibrium helps us make sense of the fossil record if we're already looking at it through an evolutionary lens. But does the fossil record itself suggest descent with modification as the most obvious explanation of how all the species came to be?

David Raup writes in Field Museum of Natural History Bulletin, commenting on the compatibility of the fossil record with Darwin's theory, "We still have a record that does show change but one which can hardly be looked upon as the most reasonable result of natural selection" (Raup, David M. "Conflicts Between Darwin and Paleontology." Field Museum of Natural History Bulletin, pp 25. Chicago, January 1979). In writing for Paleobiology, David Kitts goes even further, saying, "Few paleontologists have, I think ever supposed that fossils, by themselves, provide grounds for the conclusion that evolution has occurred" (Kitts, David B. "Search for the Holy Transformation," review of Evolution of Living Organisms, by Pierre-P Grasse, Paleobiology, vol. 5, 1975, pp 353). Mark Ridley, writing for New Scientist in 1981, voices a similar sentiment: "In any case, no real evolutionist, whether gradualist or punctuationist, uses the fossil record as evidence for evolution as opposed to special creation" (Ridley, Mark. "Who Doubts Evolution?" New Scientist, vol. 90, 1981, pp 831).

Now, none of these people are trying to say that evolution didn't happen, or that the fossil record provides evidence against it. All they are saying is that although some of the predictions generated by evolutionary theory concerning the fossil record have turned out to be true (aka., there are transitions between major groups, sometimes series exhibit change over time, etc.), the fossil record alone has not provided as robust support for the theory of evolution as we might have predicted—to the extent that theories other than evolution might do just as well at accounting for the data we have.

To return to the larger argument, then, we can conclude that although the evolutionary theory has not allowed us to replicate the accumulation of random changes through natural selection that transform one type of creature into several distinct descendant types, which it posits as the mechanism by which all species came into being, it has had some, but incomplete, predictive power with regards to the types of fossilized creatures it expects those processes to have left behind. And, as we mentioned before, it has a great deal of explanatory power.

But how complete is this power? Though scientists may be able to point to various forms complex systems may have gone through in the evolutionary process, they cannot identify exactly which mutations—which would have occurred at random—could have been responsible for changing one transitional form into another over many generations, nor can they assure us with confidence based on anything more than opinion that such accumulation of necessary mutation could have occurred randomly within the timeframes represented in the fossil record. Granted, such an explanation would require an intricate knowledge of exactly how DNA works that we do not yet possess, so the fact that the explanatory power of the evolutionary theory is incomplete is hardly surprising.

Yet, given, in combination, these shortcomings, it is hardly fair to assert that the evolutionary theory is just as good as any other scientific theory, since other theories often have more detailed explanations, more incontrovertible predictive power, and, in many cases, allow us to replicate the phenomena of which they purport to describe the causes.

Why should a few unanswered questions lead us to challenge the theory of evolution with a supernatural account of the origin of the species when we are willing to accept naturalistic accounts of just about everything else?

So, the evolutionary theory may not be as supported by the evidence as every other scientific theory, but let us grant that it remains on at least equal footing with many of them, given the partial explanatory and predictive power it retains. Why not provisionally embrace it, then, accepting that it may not be true, per se, but recognizing its incredible utility as the best naturalistic model of the origin of life we currently have, and acknowledging that if it isn't true, it is at least as accurate a model of the truth as we have yet been able to construct and that there is no competing naturalistic theory better supported by the evidence that we should suspect may be true instead, and so we might as well assume it is true until such time as there is just such a better model—as we do with all the other current models endorsed by science that nevertheless make the occasional wrong prediction or leave certain phenomena incompletely accounted for?

In fact, I would say, there is no reason not to embrace, provisionally, the evolutionary model if one's purpose in so doing is to do science, that is, to continue adjusting and fleshing out the model just to see if one day, we may be able to replicate life, and the model may explain everything that it purports to with the level of specificity that we desire. To reiterate, science must operate from the assumption that everything can be explained according to natural laws. It cannot comment on the supernatural, because the supernatural cannot be modeled, predicted, or replicated. And in order to learn as much as we can through the natural, we cannot attribute gaps in our understanding to the supernatural; we must continue trying to explain them through the natural, or we won't have a chance of making the scientific breakthroughs necessary to enlighten us as to the workings of those things we did not previously understand.

However, if one's purpose is to know truth, the question becomes a little more complicated. If one's purpose is to know truth, one cannot rule out any possibility a priori, as science rules out all supernatural explanations, because the supernatural—as science has traditionally been willing to admit—may in fact be part of the truth. But even if we admit the possibility of supernatural elements constituting part of what is true, it is not immediately obvious why we should use theories of the supernatural to challenge the theory of evolution when we are willing to let most other naturalistic theories stand unopposed, the anti-creationist may argue. If we are willing to admit supernatural possibilities--not as scientists, but as rational thinkers—then shouldn't we argue the possibility that everything is actually caused supernaturally, and that the whole enterprise of science is pretty much pointless, and it only seems to work because the supernatural elements actually at work in the universe normally operate in such a consistent way as to mimic the appearance of natural laws? Mightn't we, if we are going to allow the supernatural, throw up our hands and give up on feeling remotely confident in any of the knowledge we think we have gained through science?

Certainly, one would be free to advance such an argument. But let us not pretend that such an argument would involve exactly the same sort of logic as an argument that would challenge, for the time being, only that single scientific theory of evolution with a supernatural explanation of the origins of life. The fact that apples consistently fall to the ground, for example, does not immediately impress the mind with the idea that a magical, inexplicable force must have exercised its power upon reality to move them there. One can, of course, imagine that this is the case, but given the consistency of the effect, it seems perfectly reasonable to assume that a stable, natural force such as gravity is responsible and look no further. By contrast, pre-eminent philosophers and scientists the world over have been impressed throughout history with the elegance and complexity of life as we know it, believing it to scream 'supernatural design' as its origin. In fact, Richard Dawkins, acclaimed scientist and advocate of atheism, defines biology as 'the study of complicated things that give the appearance of having been designed for a purpose.'

Granted, just because something appears to be supernatural in origin does not mean that its origins are, in truth, supernatural. But if we, as rational thinkers, allow that some things in the universe might not be fully determined or explicable through natural causes alone, cannot we be permitted to reflect about which things it seems to us the supernatural was most likely to have played a role in bringing about? Must we be restricted to an all-or-nothing sort of reasoning, whereby we must assume that either everything or nothing has a supernatural explanation, with no room for anything in between? I admit, attempting to reason about which sorts of things the supernatural is and is not likely to have played a role in bringing about presents a unique sort of logical difficulty, given the inherent ineffability of the divine. But even in such a task as this, I would argue, we are not without tools. Though we may be stripped of the utility standard and the observable evidence criteria that are the requirements of scientific models, there remain to us at least the intuitions and reasoning of philosophers to aid us in such considerations. And philosophy, I hope, is not necessarily impotent in the quest for truth.

In Part III, we will use philosophical tools to examine these theories further.

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Beth Peterson attended Johns Hopkins University as a National Merit Scholar and a Bloomberg Scholar and graduated with a B.A. in Psychology and a minor in Acting. She has been writing fantasy fiction since her middle school years and looks forward to making her first book deal.