“Many of the most prominent neo-Darwinists have written at one time or another that natural selection is a tautology, a way of saying the same thing twice. In this formulation the theory predicts that the fittest organisms will produce the most offspring, and it defines the fittest organisms as the ones which produce the most offspring. It is important to document this point, because many Darwinists have convinced themselves that the tautology idea is a misunderstanding introduced into the literature by creationists and other uncomprehending faultfinders. But here are a few examples collected by Norman Macbeth:
J. B. S. Haldane (1935): ” … the phrase ‘survival of the fittest,’ is something of a tautology. So are the most mathematical theorems. There is no harm in saying the same truth in two different ways.
Ernst Mayr (1963): “… those individuals that have the most offspring are by definition … the fittest ones.”
George Gaylord Simpson (1964): “Natural selection favors fitness only if you define fitness as leaving more descendants. In fact geneticists do define it that way, which may be confusing to others. To a geneticists fitness has nothing to do with health, strength, good looks, or anything but effectiveness in breeding.”
The explanation by Simpson just quoted indicates why it is not easy to formulate the theory of natural selection other than as a tautology. It may seem obvious, for example, that it is advantageous for a wild stallion to be able to run faster, but in the Darwinian sense this will be true only to the extent that a faster stallion sires more offspring. If greater speed leads to more frequent falls, or if faster stallions tend to outdistance the mares and miss opportunities for reproduction, then the improvement may be disadvantageous.
Just about any characteristic can be either advantageous or disadvantageous, depending upon the surrounding environmental conditions. Does it seem that the ability to fly is obviously an advantage? Darwin hypothesized that natural selection might have caused beetles on Madeira to lose the ability to fly, because beetles capable of flight tended to be blown out to sea. The large human brain requires a skull which causes discomfort and danger to the mother in childbirth. We assume that our brain size is advantageous because civilized human dominate the planet, but it is far from obvious that the large brain was a net advantage in the circumstances in which it supposedly evolved. Among primates in general, those with the largest brains are not the ones least in danger of extinction.
In all such cases we can presume a characteristic to be advantageous because a species which has it seems to be thriving, but in most cases it is impossible to identify the advantage independently of the outcome. That is why Simpson was so insistent that ‘advantage’ has no inherent meaning others than actual success in reproduction. All we can say is that the individuals which produced the most offspring must have had the qualities required for producing the most offspring.
The famous philosopher of science Karl Popper at one time wrote that Darwinism is not really a scientific theory because natural selection is an all purpose explanation which can account for any thing, and which therefore explains nothing. Popper backed away from this position after he was besieged by indignant Darwinists protests, but he had plenty of justification for taking it. As he wrote in his own defense, ‘some of the greatest contemporary Darwinisits themselves formulated the theory in such a way that it amounts to the tautology that those organisms that leave most offspring leave most offspring,’ citing Fisher, Haldane, Simpson, ‘and others.’ One of the others was C. H. Waddington, whose attempt to make sense of the matter deserves to be preserved for posterity:
Darwin’s major contribution was, of course, the suggestion that evolution can be explained by the natural selection of random variations. Natural selection, which was at first considered as though it were a hypothesis that was in need of experimental or observational confirmation, turns out on closer inspection to be a tautology, a statement of an inevitable but previously unrecognized relation. It states that the fittest individuals in a population (defined as those which leave the most offspring) will leave the most offspring. This fact no way reduces the magnitude of Darwin’s achievement; only after it was clearly formulated, could biologists realize the enormous power of the principle as a weapon of explanation.
That was not an offhand statement, but a considered judgment published in a paper presented at the great convocation at the University of Chicago in 1959 celebrating the hundredth anniversary of the publication of the Origin Of Species. Apparently, none of the distinguished authorities present told Waddington that a tautology does not explain anything. When I want to know how a fish can become a man, I am not enlightened by being told that the organisms that leave the most offspring are the ones that leave the most offspring.
It is not difficult to understand how leading Darwinists were led to formulate natural selection as a tautology. The contemporary neo-Darwinian synthesis grew out of population genetics, a field anchored in mathematics and concerned with demonstrating how rapidly very small mutational advantages could spread in a population. The advantages in question were assumptions in a theorem, not qualities observed in nature, and the mathematicians naturally tended to think of them as ‘whatever it was that caused the organism and its descendants to produce more offspring than other members of the species.’ This way of thinking spread to the zoologists and paleontologists, who found it convenient to asume that their guiding theory was simply true by definition. As long as outside critics were not paying attention, the absurdity of the tautology formulation was in no danger of exposure.
What happened to change this situation is that Popper’s comment received a great deal of publicity, and creationists and other unfriendly critics began citing it to support their contention that Darwinism is not really a scientific theory. The Darwinists themselves became aware of a dangerous situation, thereafter critics raising the tautology claim wer firmly told that they were simply demonstrating their inability to understand Darwinism….In practice natural selection continues to be employed in its tautological formulation.
… Although natural selection can be formulated as a tautology, and often has been, it can also be formulated in other ways that are not so easily dismissed.
Phillip Johnson
Darwin On Trial — pp. 20-23