As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.
The implications of the theory of evolution for man’s place in nature were obvious. Darwin himself noted that “the conclusion that man is the co-descendant with other species of some ancient, lower, and extinct form is not in any degree new. Lamarck long ago came to this conclusion, which has lately been maintained by several eminent naturalists and philosophers; for instance, by Wallace, Huxley, Lyell, Vogt, Lubbock, Buchner, Rolle, &c., and especially Haeckel.”
In the eighteenth century, de Lamettrie had classified man as an animal in L ‘Homme Machine (1748). Linnaeus (1707–1778) had classified man with the manlike apes as Anthropomorpha. T. H. Huxley in his famous “Man’s Relations to Lower Animals,” begins his account by looking at the development of a dog’s egg, and then concludes that
The history of the development of any other vertebrate animal, Lizard, Snake, Frog, or Fish, tells the same story. There is always, to begin with, an egg having the same essential structure as that of the Dog:—the yolk of that egg always undergoes division, or “segmentation”;…the ultimate products of that segmentation constitute the building materials for the body of the young animal; and this is built up round a primitive groove, in the floor of which a notochord is developed. Furthermore, there is a period in which the young of all these animals resemble one another, not merely in outward form, but in all essentials of structure, so closely, that the differences between them are inconsiderable, while, in their subsequent course, they diverge more and more widely from one another.
Thus the study of development affords a clear test of closeness of structural affinity, and one turns with impatience to inquire what results are yielded by the study of the development of Man. Is he something apart? Does he originate in a totally different way from Dog, Bird, Frog, and Fish, thus justifying those who assert him to have no place in nature and no real affinity with the lower world of animal life? Or does he originate in a similar germ, pass through the same slow and gradually progressive modifications—depend on the same contrivances for protection and nutrition, and finally enter the world by the help of the same mechanism? The reply is not doubtful for a moment, and has not been doubtful any time these thirty years. Without question, the mode of origin and the early stages of the development of man are identical with those of the animals immediately below him in the scale:—without a doubt, in these respects, he is far nearer the Apes, than the Apes are to the Dog.
There is every reason to conclude that the changes [the human ovum] undergoes are identical with those exhibited by the ova of other vertebrated animals; for the formative materials of which the rudimentary human body is composed, in the earliest conditions in which it has been observed, are the same as those of other animals.
But, exactly in those respects in which the developing Man differs from the Dog, he resembles the ape, which, like man, has a spheroidal yolk-sac and a discoidal—sometimes partially lobed—placenta.
So that it is only quite in the later stages of development that the young human being presents marked differences from the young ape, while the latter departs as much from the dog in its development, as the man does.
Startling as the last assertion may appear to be, it is demonstrably true, and it alone appears to me sufficient to place beyond all doubt the structural unity of man with the rest of the animal world, and more particularly and closely with the apes.
The evidence for evolution comes from an impressive range of scientific disciplines: systematics, geopaleontology, biogeography, comparative studies in biochemistry, serology, immunology, genetics, embryology, parasitology, morphology (anatomy and physiology), psychology, and ethology.
This evidence points in the same direction, namely, that man, like all living things, is the result of evolution, and was descended from some apelike ancestor, and certainly was not the product of special creation. In this context, to talk of Adam and Eve as both the Bible and Koran do is meaningless. Man is, at present, classified under the order primates, along with tree shrews, lemurs, lorises, monkeys, and apes. Thus, not only apes and monkeys, but lemurs and tree shrews must be considered our distant cousins. As J. Z. Young states, “It is harder still to realize that our ancestry goes on back in a direct and continuous father-and-son line to a shrew, and from there to some sort of newt, to a fish, and perhaps to a kind of sea-lily.”
Has the famous story that stands at the beginning of the Bible really been understood? the story of God’s hellish fear of science?…Man himself had turned out to be [God’s] greatest mistake; he had created a rival for himself; science makes godlike—it is all over with priests and gods when man becomes scientific…. Knowledge, the emancipation from the priest, continues to grow.
Nowhere in the foregoing account of the origins of the universe and the origin of life and the theory of evolution did I have recourse to “divine intervention” as an explanation. Indeed, to explain everything in terms of God is precisely not to explain anything—it is to cut all inquiry dead, to stifle any intellectual curiosity, to kill any scientific progress. To explain the wonderful and awesome variety and complexity of living organisms as “miracles” is not to give a very helpful, least of all a scientific, explanation. To quote Dawkins, “To explain the origin of the DNA/protein machine by invoking a supernatural Designer is to explain precisely nothing, for it leaves unexplained the origin of the Designer. You have to say something like ‘God was always there,’ and if you allow yourself that kind of lazy way out, you might as well just say ‘DNA was always there,’ or ‘Life was always there,’ and be done with it.”
Darwin made the same point about his own theory in a letter to Sir Charles Lyell, the famous geologist: “If I were convinced that I required such additions to the theory of natural selection, I would reject it as rubbish…. I would give nothing for the theory of natural selection, if it requires miraculous additions at any one stage of descent.” Quoting the above letter, Dawkins comments: “This is no petty matter. In Darwin’s view, the whole point of the theory of evolution by natural selection was that it provided a non-miraculous account of the existence of complex adaptations. For what it is worth, it is also the whole point of this book [The Blind Watchmaker]. For Darwin, any evolution that had to be helped over the jumps by God was not evolution at all. It made a nonsense of the central point of evolution.”
As for the big bang and modern cosmology, Stephen Hawking makes the same point. Trying to make amends for their treatment of Galileo, the Vatican organized a conference to which eminent cosmologists were invited.
At the end of the conference the participants were granted an audience with the pope. He told us that it was all right to study the evolution of the universe after the big bang, but we should not inquire into the big bang itself because that was the moment of Creation and therefore the work of God. I was glad then that he did not know the subject of the talk I had just given at the conference—the possibility that space-time was finite but had no boundary, which means that it had no beginning, no moment of Creation. (Hawking, Chapter 14)