There is another aspect of the question which must by no means be overlooked. It has to be assumed that Natural Selection, or the survival of the fittest in the struggle for existence, necessarily tends to the benefit of the race and moreover to its farther development on the upward grade, towards a more perfect and more specialized organization;—in Mr. Herbert Spencer's words, to progression from a relatively indefinite incoherent homogeneity, to a relatively definite, coherent heterogeneity. But here many questions occur.
In the first place, a consideration presents itself, which appears to furnish the most formidable of all difficulties in the way of Mr. Darwin's hypothesis. How can this struggle for existence be supposed to have any tendency to promote organic development to ever higher and more perfect types, in the orderly sequence which has in fact occurred? The "Survival of the fittest" means only the survival of the fittest to survive,—of such as can find means of living where others cannot. Unless it can be shown[{187}] that increased complexity of organization necessarily brings with it such increased vitality, Natural Selection can do nothing for organic development. If the mere power of living be the only factor in the process, as on Mr. Darwin's showing it is, a man is only a more complicated and delicate machine for securing the same object which can equally well, or better, be attained by a mole, a cockroach, or a microbe. And who will say that, so far as this particular end is concerned, he is better equipped than creatures which all the resources of civilization are powerless to exterminate?
That practical advantage in the struggle for existence must necessarily accompany increased specialization of organs, and thus produce a "higher" organization, was a prime point of Mr. Darwin's argument, though at the same time he found himself compelled to encumber it with qualifications which go very far to neutralize its force; for he had to explain the obvious fact that so many creatures which represent the lowest and least specialized forms of life, have survived down to our own time. Thus he writes:[222]
The degree of differentiation and specialization of the parts in organic beings, when arrived at maturity, is the best standard, as yet suggested, of their degree of perfection or highness. As the specialization of parts is an advantage to each being, so natural selection will tend to render the organization of each being more[{188}] specialized and perfect, and in this sense higher; not but that it may leave many creatures with simple and unimproved structures fitted for simple conditions of life, and in some cases will even degrade or simplify the organization, yet leaving such degraded beings better fitted for their new walks of life.
By this fundamental test of victory in the battle of life, as well as by the standard of the specialization of organs, modern forms ought, on the theory of Natural Selection, to stand higher than ancient forms. Is this the case? A large number of palæontologists would answer in the affirmative; and it seems that this answer must be admitted as true, though difficult of proof.
That is to say, Natural Selection is just as ready to degrade as to elevate a creature, according to the actual requirements of the circumstances in which it is placed, and how far progress has been the rule, rather than stability or retrogression, is a question for geological history to determine. This we shall have to consider in our next chapter.
It is likewise obvious that so far as the mere struggle for existence is concerned, a species each of whose individual members is but poorly furnished, may nevertheless flourish unimpaired on the mere strength of its fecundity. It is thus, says M. Blanchard,[223] that the lower forms of life continue to hold their own despite the enormous ravages to which they are subject. The herring,[{189}] for example, affords food to all the fowls of the air and fish of the sea, over and above the myriads annually requisitioned by man. Yet its hosts show no sign of being exterminated or even reduced. Much the same is the case of the cod; but a tribe one individual of which has been known to produce nine million eggs does not require much in the way of coherent heterogeneity to ensure its survival.
Thus it appears that of itself Darwinism affords no explanation whatever of the regular progression of life forms from lower to higher, to which the records of Nature bear witness, and which is the one solid fact suggesting the idea of Evolution.
Such are some of the reasons which, on purely rational grounds, appear amply to justify those who decline to pledge their faith to Darwinism, in spite of the popularity it enjoys. But what is to be said of the phenomena cited as furnishing positive and unimpeachable evidence in its favour, which were mentioned above in our sketch of its main features?
First as to the rudimentary, fragmentary, or vestigial organs so common in Nature. These, it is said, being of no possible advantage to their possessors, and often a serious disadvantage, can be explained only by supposing that they were serviceable in the past to the ancestral race whence these possessors are derived, and have since been superseded by other modifications of structure, so as to dwindle away by disuse. This, no doubt, seems a very plausible explanation, but it does not follow that we[{190}] ought immediately to adopt it as a certainty, instead of setting ourselves to examine how it accords with all the facts. Nothing is more dangerous and less scientific than to be in a hurry to conclude that everything is certain which seems to ourselves probable, especially if it suits a theory of our own. Unfortunately, this law is too frequently more honoured in the breach than the observance. In the present instance, Professor Haeckel himself furnishes an example. He is quite sure that the rudimentary structures can have but one significance, and that they are fatal to the idea of purpose in Nature, the object of his special aversion, and so he has proposed a new term, "Dysteleology," to embody this idea, of which he says,[224]