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KRONOS Vol VII, No. 4
DARWIN'S UNFALSIFIABLE THEORY
"Darwin's Mistake" was published in the February, 1976 issue of Harper's magazine. In it I pointed out what struck me then, and still strikes me today, as a glaring error in Darwin's theory of evolution by natural selection. Incidentally, in talking about "the theory of evolution" it is important to maintain the distinction between the general theory of evolution - the theory that evolution took place and Darwin's theory as to how it took place - natural selection. Admittedly, Darwin, himself constantly blurs the distinction between these two theories in The Origin of Species. In any event, my quarrel here is with the theory as to how evolution occurred. Darwin observed that there is a range of variation in the members of a species. Since organisms live in an environment, thought of as a niche into which the organism more or less snugly fits, it follows that some organisms are better fitted to their surroundings than others. These fitter organisms will in turn tend to survive better and leave more offspring than those that are less fit. Hence, over time, there is a greater and greater preponderance of more rather than less fit organisms. So evolution takes place. Nature slowly improves. Herbert Spencer characterized the process by which this occurred as "the survival of the fittest". Darwin thought this an admirable summation of his theory.
If you look back over the preceding paragraph, you may be able to spot the error in the argument. The words "fit," "fitter" and "fittest" are used in an ambiguous way. "Fitness" parades itself as an objective, discernible characteristic of organisms. Some animals have more of it; others less. Those that have more tend to win out in the "struggle for existence," so perpetuating their kind. So evolution takes place and progress occurs. This quality of "fitness" becomes more widely disseminated through the generations.
In fact, however, it turns out that the only way we are able to discern this elusive quality of "fitness" is by examining the survivors. They define fitness. Darwin proposed no criterion of fitness other than that of survival itself. Nor did any of Darwin's followers in the years and decades since the publication of The Origin. If this is true, as I have no doubt that it is, it follows that "the survival of the fittest" is not a testable theory, but a tautology. Which ones survive? The fittest. Who are they? Those that survive.
The scientist, or the philosopher of science, might put the problem with Darwin's theory this way. No event, or observation in nature, could conceivably demonstrate that the theory was false. To some this might at first seem to be a strength rather than a weakness of the theory, but in fact of course a theory that cannot be falsified in principle is not "true" but rather a semantically disguised statement of the type "all apples are apples".
In October, 1976 Stephen Jay Gould, the well known Harvard paleontologist, responded in Natural History magazine to my article, and subsequently reprinted his response in a collection of his essays entitled Ever Since Darwin (Norton, 1977). He conceded my main point, that, in the absence of an independent criterion of fitness, Darwin's theory is reduced to a tautology. But, he then argued, the theory was safe and sound because it already did include just such an independent criterion. "Certain morphological, physiological and behavioral traits should be superior a priori as designs for living in new environments," Gould wrote. "These traits confer fitness by an engineer's criterion of good design, not by the empirical fact of their survival and spread."
Gould does not develop this argument at all. But his key idea is that of an "engineer's criterion of good design". It is perfectly true that, from an engineer's point of view, there is such a thing as "good design" that is independent of the particular machine that incorporates that design. But still, "good design" cannot be regarded as a wholly independent quality. It would be possible for an engineer to claim that the wing of an airplane was well or badly designed - but only if he knew the function of the airplane. If it is meant to break the sound barrier, then one wing shape would constitute good design. But if it is meant to carry heavy cargo, the same wing shape would be bad design.
Once this point is clarified, we can see that the analogy between biology and engineering breaks down, because evolutionary biology as currently set forth by such experts as Gould himself does not recognize the idea that animals have any ultimate function other than to survive and leave offspring. It can plausibly be argued from an engineer's standpoint that various birds are badly designed - ostriches and flamingoes, for example - but if they succeed in surviving and leaving offspring, as they do, who is to say that they are defective from an engineer's point of view? Certainly not Steve Gould, I'll warrant.
The engineering analogy breaks down when analysing the "design" of parts of organisms, because, from the evolutionist's point of view, it is the overall animal that survives (or does not survive), not individual parts of it. In short, if it survives and leaves offspring, then it is "fit" from the evolutionist's point of view, no matter how weird or improbable an assemblage of flesh and bones it might seem to be to one trained in mechanics or aerodynamics. One can see that this is merely another way of saying that fitness is inevitably defined by survival, and cannot be assessed independently of it. Gould's engineering analogy, then, fails to break the tight semantic connection between the concepts of "fitness" and "survival". If Gould is prepared to admit that organisms have a function (other than leaving offspring) then I shall be prepared to admit the notion of good design. If, for example, Gould will tell me that the function of the leopard is to run rapidly, then I will admit to him that the leopard's legs are well engineered. This simple example shows that the idea of "good design" is entirely subordinate to the idea of function, and as such it cannot be brought in as an objective, independent quality that rescues natural selection from tautology.
This issue is further complicated by one more consideration. If an animal is in fact observed to survive and flourish in a given environment, then the biologist is perfectly capable of subsequently enumerating those traits that contribute to this success. For example he can point out - as has been done in the case of moths - that dark coloring is helpful to moths that sleep on dark tree trunks when predator birds are in the offing. Such coloring (it has been adequately demonstrated) makes it difficult for the birds to spot the moths, thus contributing to the survival of the dark moths and their descendants.
However, this observed relationship between moth-color and moth-survival does not constitute "verification" of Darwin's theory that the fittest survive by virtue of some independently isolable quality of "fitness". It merely verifies the theory that camouflage is helpful to moths in a particular environment. One can easily appreciate this point by considering the biologist's reaction if the camouflage hypothesis were, much to his surprise, falsified; that is, if dark moths in another part of the woods (or the world) did not survive as abundantly as other, more visible strains even though the tree trunks remained dark and other aspects of the environment seemed similar.
Would the biologist, faced with such a finding, triumphantly report that he had falsified Darwin's theory of natural selection? No. He would merely conclude that some other factor he did not know about was operating in the environment - one that he had not hitherto considered.
It follows, then, that darkness in moths is not an independent criterion of fitness, leading ineluctably to survival and offspring, but merely one factor (among thousands) that contributes to survival in a given environment, or set of circumstances. Every week ecologists perform experiments testing hypotheses about the usefulness of various animal traits, and frequently such hypotheses are not confirmed. In no instance, however, do they then make the claim that Darwin's theory has been overthrown. And in fact no experimental observation will ever lead to such a claim, precisely because Darwin's theory is immune - logically immune - to falsification.
There is one final point. If it is true that the theory of natural selection is so vacuous that no experiment can in principle either verify or falsify it, then how has it managed to survive as satisfactorily as it has for over 120 years? I think the reason why biologists cling to it so tenaciously is that, if natural selection were swept away, then the general theory of evolution itself - the theory that evolution has occurred - would stand perilously exposed to doubt. (It is of course nonsense to say, as some ardent evolutionists do, that the general theory of evolution is now a "fact". This theory may be summarized as the hypothesis that all organisms now, and all organisms throughout history, have parents, or one parent. It is true that no observation has yet decisively falsified this theory - and one can see that unlike natural selection in principle it is falsifiable, and thus it is within the boundaries of science - but it is also very far from being so well established that it is reasonable to regard it as a "fact".) If the general theory of evolution were overthrown, then the authority of science itself would be seriously undermined. This is because if the theory of evolution is false, then the principle of the uniformity of nature no longer holds true, and materialism's hegemony is ended (See Bethell, The American Spectator, March 1982, pp. 5-6, 40). So a lot rides on the preservation of the theory of evolution.
In his strange new book Life Itself: Its Origin and Nature (Simon & Schuster, 1981) Francis Crick shows just how much the plausibility of the theory of evolution in turn rests upon the foundation stone of natural selection. And indeed, we may recall that in Darwin's day the theory that evolution had occurred was not regarded as plausible until Darwin had shown how it might have occurred. Crick points out that the odds against life appearing by chance are very long indeed - so long as to be regarded as impossible without the "mechanism" of natural selection. "As far as we know," Crick writes, "there is no other mechanism which can be relied on to produce comparable results so efficiently."
Without natural selection, the evolution of life as we know it from primeval soup by random mutation becomes hopelessly implausible. Therefore either natural selection stays, or evolution goes. Biologists, in deference to the status of science, have put aside their differences and their doubts and have opted for the former.