« 이전계속 »
Qui vivra, verra. At any rate Darwinians have no right to assert that their leader's hypothesis is proved. On the contrary, the way in which we are continually put off with possibilities when we compare the theory with actual facts, raises well founded doubts as to the theory itself. Even with reference only to what I have spoken of-and the principal point is still to come, I think we may say with J. B. Meyer," that “Darwinism is not condemned because it sets up hypotheses, but because these hypotheses are bad. No science can exist without hypotheses, and good hypotheses may be of great service to a science. But we can only admit them in order to explain existing facts; and we cannot admit those hypotheses which require for their support not only other hypotheses, but also facts which are entirely unproved. Now the Darwinian theory requires many such hypotheses, and therefore it is scientifically wrong and inadmissible.”” .
The explanation of undoubted facts is here rightly said to be the object of scientific hypotheses. The more completely and simply a hypothesis explains the facts in question, the more plausible it is. I have shown by several examples that the Darwinian theory does not explain many important facts, or at least cannot explain them without having recourse to further hypotheses. There are no doubt certain groups of facts in the face of which the Darwinian theory appears to a superficial observer an attractive, and according to its supporters the only satisfactory hypothesis. The existence of the so-called rudimentary organs belongs to these. By the rudimentary organs are meant those parts of the body which are intended for a special purpose, and yet have no functions. In some animals which live in caves or under the earth, and which therefore can never use their eyes, we find hidden under the skin real eyes, or something resembling real eyes, but these eyes cannot perform their functions because they are covered with an opaque membrane, and therefore cannot be reached by the light. It is supposed that in the ancestors of these animals, which lived in the daylight, the eyes were well developed, were covered by a horny transparent capsule, and actually served the purpose of seeing. As the animals accustomed themselves by degrees to an underground mode of life, and withdrew from the light of day, they no longer used their eyes, the latter then deteriorated more and more from generation to generation, so that at last only the rudiments of eyes remained." Darwin explains that the wings of those birds and insects which live in islands, and therefore need not fly much or far, grow stunted in this way. He goes farther, and assumes that those kinds of birds which are called running birds, whose legs, like those of the ostrich and cassowary are strongly developed, and whose wings are very slightly developed, are descended from birds which had stronger wings, that they had got out of the habit of flying, had thus lost the use of their wings, and had therefore preserved only rudimentary wings. The stunting of the wings among birds and insects According to Baer, however, this is doubtful. See Studien, p. 437.
* Philos. Zeitfragen, p. 103. * Cf. Haeckel, Mat. Schöpfungsgeschichte, p. 126. Anthropogenie, pp. 86,692.
which lived on islands is explained in this manner; those that flew well and much were while flying blown by the wind into the sea; those that flew ill therefore had in this case an advantage in the struggle for existence, they were not so easily blown into the sea, and remained alive longer than individuals of the same kind that flew well. And therefore, in the course of of several generations, the wings became gradually stunted by the process of natural selection. For instance, in the island of Madeira, out of five hundred and fifty kinds of beetles, two hundred had no wings, or wings so imperfect as to make flying impossible. No doubt it is not unlikely that a gradual stunting actually took place among many species of birds, but it is rather hazardous to generalize from this, and to explain all the so-called rudimentary organs in this way. It is possible that among many species the rudimentary form of the organ is the original one, and that it stands in its proper relation to the whole organization. If organs which are not used not only gradually grow stunted but at last disappear,' we cannot understand why several of the so-called rudimentary organs, if they are really useless to the animal, have not disappeared altogether; as, for instance, the nipples in male mammals, and the rudimentary toes at the side of a horse's foot.” It does not follow that because the ostrich has wings like all other birds, therefore it ought to have equally useful wings, and that its ancestors must have had wings as useful as those of the eagle. If we assume this, we are supposing the very thing which has to be proved, namely, that all differences between animals must have arisen by gradual transformation. This may be assumed where it can be proved by observation or induction, but if we go farther, we are leaving the region in which hypothesis is justifiable, and we find ourselves believing startling things, such as Haeckel and Darwin sometimes tell us, as, for instance, that in the so-called tail vertebrae, man has a rudimentary tail, and that during the two first months of the development of the human embryo this stands out, and only grows in later. “This rudimentary little tail of man is,” as Haeckel says,” an irrefutable proof of the fact that he is descended from tailed ancestors.”.” Or, most men are not capable of moving their ears at will, although the muscles for moving them exist. By means of continued practice some men succeed in accomplishing the feat of moving their ears at will. Therefore the muscles which accomplish this exist in man, only they are stunted, therefore man is descended from ancestors who had moveable ears, like many animals. It would be far more important if the Darwinian theory professed to explain not only the stunting of separate organs, and their gradual perfecting, but also the growth of new organs. For instance, how did the eyes originate which do not exist in animals of low organization, and according to the Darwinian theory did not exist in the ancestors of the more highly organized animals.” Haeckel thinks that comparative anatomy and the history of development shows us in the animal kingdom such a gradual perfecting of the eyes, that it is quite possible to imagine from it what must have been the gradual development of these organs in the course of ages, through all stages of perfection. In the lowest animals the eye appears as a simple spot of colour, which cannot reflect any picture of outward objects, and is at most sensitive to the different rays of light. To this is added a sensitive nerve. Later on, the first beginning of the lens is gradually developed inside this spot of pigment, a refracting body which is able to concentrate the rays of light, and to reflect a distinct picture. But all the complicated apparatus for focussing and moving the eye is still wanting, the additional refracting media, the highly differentiated membrane of the optic nerves, etc., which make the eye such a perfect organ among the higher animals. Comparative anatomy therefore shows in a series of unbroken steps all the possible transitions from the simplest possible organs to the most complete apparatus, and we can therefore quite well imagine the gradual development, even of so complicated an organ as this. If any one does not understand this, and in contemplating these most perfect organs still believes that an external Creator is necessary, he resembles the savages, Haeckel loves such comparisons as these, who seeing for the first time a ship of war, or a locomotive, thought that these objects must be produced by supernatural beings, and could not understand that such an apparatus could be produced by a man, organized as they were."
* Haeckel, Mat. Schöpfungsgeschichte, p. 223. * Huber, Zur Kritik, p. 14. Michelis, Hackelogonie, p. 80.
* Mat. Schöpfungsgeschichte, p. 258. * Haeckel, Mat. Schöpfungsgeschichte, p. 11. Anthropogenie, p. 563.