" 'Survival of the fittest' and 'natural selection.' No matter what phraseology one generates, the basic fact remains the same: any physical change of any size, shape or form is strictly the result of purposeful alignment of billions of nucleotides (in the DNA). Nature or species do not have the capacity for rearranging them, nor adding to them. Consequently no leap (saltation) can occur from one species to another. The only way we know for a DNA to be altered is through a meaningful intervention from an outside source of intelligence: one who knows what it is doing, such as our genetic engineers are now performing in their laboratories."

Charles Darwin made the concept of major evolutionary change plausible by convincing scientists that natural selection could account for the appearance of design in nature (Horan, 1979). He would never have considered evolution to be a fact without a plausible theory of how it could occur. The very title of his book reflects the importance of an evolutionary mechanism. Although much evidence has been cited in favor of macroevolution, as it had been prior to 1859, such evidence in Darwin's own opinion would be unsatisfactory without a mechanism:

"In considering the Origin of Species, it is quite conceivable that a naturalist, reflecting on the mutual affinities of organic beings, on their embryological relations, their geographical distribution, geological succession, and such other facts, might come to the conclusion that each species had not been independently created, but had descended, like varieties, from other species. Nevertheless, such a conclusion, even if well founded, would be unsatisfactory, until it could be shown how the innumerable species inhabiting this world have been modified, so as to acquire that perfection of structure and coadaptation which most justly excites our admiration."

"The essence of Darwinism lies in a single phrase: natural selection is the creative force of evolu-tionary change. No one denies that selection will play a negative role in eliminating the unfit. Darwinian theories require that it create the fit as well."

"It is fair to say that Darwin simply assumed that gradual improvement was possible in general... Darwin's assumption, I will try to show, was almost certainly wrong. It does not appear to be the case that gradualism always hold. In some complex systems, any minor change causes catastrophic changes in the behavior of the system. In these cases ... selection cannot assemble complex systems. Here is one fundamental limit to selection."

"... natural selection over the long run does not seem to improve a species' chance of survival but simply enables it to 'track', or keep up with, the constantly changing environment."

Darwin was not without his critics. In his book, Darwinism: The Refutation of a Myth, Soren Lovtrup points out that "some critics turned against Darwin's teachings for religious reasons, but they were a minority; most of his opponents ... argued on a completely scientific basis." He goes on to explain:

"...the reasons for rejecting Darwin's proposal were many, but first of all that many innovations cannot possibly come into existence through accumulation of many small steps, and even if they can, natural selection cannot accomplish it, because incipient and intermediate stages are not advantageous."

Perhaps the most formidable of Darwin's critics was St. George Mivart. His major book, On the Genesis of Species, took aim at the notion that natural selection could account for the accumulation of the incipient stages of useful structures (Mivart, 1871). Stephen Jay Gould notes that

"Darwin offered strong, if grudging, praise and took Mivart far more seriously than any other critic...Mivart gathered, and illustrated "with admirable art and force" (Darwin's words), all objections to the theory of natural selection---"a formidable array" (Darwin's words again). Yet one particular theme, urged with special attention by Mivart, stood out as the centerpiece of his criticism. It remains today the primary stumbling block among thoughtful and friendly scrutinizers of Darwinism. No other criticism seems so troubling, so obviously and evidently "right" (against a Darwinian claim that seems intuitively paradoxical and improbable).

Mivart awarded this criticism a separate chapter in his book, right after the introduction. He also gave it a name, remembered ever since. He called it "The Incompetency of 'Natural Selection' to account for the Incipient Stages of Useful Structures." If this phrase sounds like a mouthful, consider the easy translation: we can readily understand how complex and full developed structures work and owe their maintenance and preservation to natural selection---a wing, an eye, the resemblance of a bittern to a branch or of an insect to a stick or dead leaf. But how do you get from nothing to such an elaborate something if evolution must proceed through a long sequence of intermediate stages, each favored by natural selection? You can't fly with 2% of a wing or gain much protection from an iota's similarity with a potentially concealing piece of vegetation. How, in other words, can natural selection explain these incipient stages of structures that can only be used (as we now observe them) in much more elaborated form?"

Gould goes on to point out that among the difficulties of Darwinian theory "one point stands high above the rest: the dilemma of incipient stages. Mivart identified this problem as primary and it remains so today."

Dr. Robert Macnab of Yale University concluded a major 50 page review of the sensory and motor mechanism of the bacterium, E. coli, with these remarks:

"As a final comment, one can only marvel at the intricacy in a simple bacterium, of the total motor and sensory system which has been the subject of this review and remark that our concept of evolution by selective advantage must surely be an oversimplification. What advantage could derive, for example, from a "preflagellum" (meaning a subset of its components), and yet what is the probability of "simultaneous" development of the organelle at a level where it becomes advantageous?"

"Is Archaeopteryx the ancestor of all birds? Perhaps yes, perhaps no: There is no way of answering the question. It is easy enough to make up stories of how one form gave rise to another, and to find reasons why the stages should be favored by natural selection. But such stories are not part of science, for there is no way of putting them to the test."