1. There are not, as was at one time commonly supposed, broad and distinct lines of demarcation between the different varieties of animals and plants. Our increasing knowledge of zoology has brought to light the fact that one species shades off into another by almost imperceptible gradations. As we go back in the fossil records of animal life in the past, we find that the species now existing, while they are closely allied to correspondent species of an earlier period, are scarcely ever identical with them, and that the few cases of ident.i.ty which do occur, are limited to the most recent rocks. Either then the old species must have perished, and new ones, similar but not identical, must have been created to take their places, or there must have been a process of gradual change, by which the present species have been derived from their predecessors. In one or two cases fossils have been found which combine, to some extent, forms which are now found in distinct species, as if the process of variation had proceeded in distinct lines from a common source.

2. No two animals of any cla.s.s are exactly alike in all points.

Each has its individual peculiarities, and in some cases these peculiarities are strongly marked.

3. Man has been enabled, to a certain extent, to make use of these individual peculiarities, and by means of them to produce great varieties in the breeds of domesticated animals. This has been sometimes done unconsciously through a selection influenced by other motives, and then the process has been very slow; but latterly intentionally, with a view to the production of improved breeds, and whenever this has been the case, changes of considerable extent have been rapidly produced. By carefully selecting the animals to be paired, any desired modification can generally be produced in the course of a few generations. This is exemplified in the numerous and increasing varieties of the breeds of almost all domestic animals and birds.

The theory of Evolution then suggests that the same processes which are employed by the cattle-breeder have been in operation through untold ages. For the intention and care of the human agent, Mr. Darwin subst.i.tutes two principles; one designated as "Natural Selection," the other as "s.e.xual Selection." For their full development he claims unlimited time. The ground on which the Process of Natural Selection is maintained is as follows:--

It has been already noticed that no two individuals of the same kind are exactly alike in all respects; each individual has some peculiarities, generally very trifling, but sufficient to distinguish it from all other individuals. Some of these peculiarities will probably be such as to be of some service to the individual in the struggle of life; they will a.s.sist it in procuring food, or in resisting or escaping from its natural enemies, while on the other hand the peculiarities of other individuals will be prejudicial to them in these ways. The consequence will be that a larger proportion of those having favourable peculiarities will survive and propagate their kind; their offspring will inherit the peculiarities of their parents, and reproduce them in various degrees. The same process will then be repeated, and thus from generation to generation the peculiarity will be increased, till at last it is sufficient to mark out, first a new variety, then a new species, and so on. This process then, continued through a long course of ages, was at one time considered by Mr. Darwin sufficient to account for all the varieties of living creatures now existing, or that have existed in past ages. But he has more recently satisfied himself [Footnote: Descent of Man, vol. i p. 152.] that there are many phenomena which are not satisfactorily accounted for by this principle, since many of the specific differences of animals are found to exist in matters which, cannot directly promote their success in the struggle of life. Such, for instance, are the brilliant colours which are found, especially among the males, in many species of birds. These he proposes to explain by the supplementary theory of "s.e.xual Selection." His suggestion is that these peculiarities are in some way attractive to animals of the opposite s.e.x, so that the individuals in which they are most strongly developed are more successful than others in obtaining mates, and that in this way the peculiarity is gradually fixed and increased.

By these two processes, then, Mr. Darwin supposes that all the differences now existing among animals have been produced and perpetuated; and not only that, but that man also is the result of similar processes, acting through a very long period; that the progeny of certain "anthropomorphous apes" have, by slow degrees, risen in the scale of being above their progenitors; that all our faculties, intellectual and moral as well as physical, differ from those possessed by lower animals in DEGREE only, and not in KIND, [Footnote: Descent of Man, chaps, ii.-v.] so that man has arrived at his present state by what may be termed purely natural processes, without the intervention of any external power.

In considering these theories, our attention must first be directed to some defects which appear to weaken the whole course of the argument; and then we may consider the peculiar difficulties in the way of the processes of natural and s.e.xual selection; and the grounds for the belief that man is in possession of something entirely different in KIND from any faculty or power possessed by any lower animals, which could not therefore be derived by inheritance and improvement.

The first thing which strikes us in Mr. Darwin's works is that, from time to time, he betrays a sort of latent consciousness that his theory is insufficient; that the processes to which he ascribes such vast results are not quite adequate to the purpose, but that they need in some way to be supplemented. Every now and then recourse is had to some law--some unknown cause--which must co-operate in the production of the results he is considering. In spite of the apparent care which he has taken to guard against it, he is continually betrayed into a confusion between the two senses in which the word "law" is employed. In its proper significance, law is an expression of the will of an intelligent superior, enforced by adequate power. In this sense the law may be considered as an efficient cause. The combination of will and power is an adequate cause for any result whatever. But Mr. Darwin expressly excludes this sense of the word, in a sentence which seems to involve a self-contradiction. "I mean by nature only the aggregate action and product of many natural laws, and by law only the ascertained sequence of events." [Footnote: Plants and Animals under Domestication, vol. i. p. 6.] Law, in this sense, then, is simply the statement of observed facts, and as such can have no action at all. It a.s.serts that certain phenomena do uniformly follow each other in an ascertained order; but it gives us no information whatever as to the cause of those events, or the reason why they do thus succeed each other. But, taking law in this last sense, by his own definition, Mr. Darwin does, nevertheless, continually bring forward certain "laws" as accounting for certain results. Thus, we have the laws of "Correlation of Growth," [Footnote: Origin of Species, ed. 1872, p. 114.] "Inheritance limited to Males," [Footnote: Descent of Man, vol. i. pp. 256, 257.] and a "Principle of Compensation."

[Footnote: Origin of Species, p. 117.] When Mr. Darwin, therefore, brings forward these laws as efficient causes, he not only tacitly admits the inadequacy of his theory to account for the phenomena in question, but he also endeavours to supply the defect by another cause, which, by his own definition, is no cause at all.

And further, Mr. Darwin calls in the action of "unknown agencies."

[Footnote: Descent of Man, vol. i. p. 154.]

But it may be said, "Is not this the case with all sciences, at least in their earlier stages? Are there not frequently, or always, many phenomena which at first seem inexplicable, but which are gradually accounted for as knowledge increases? If, then, this is no objection in scientific pursuits generally, why should it be so here?" This reasoning would be perfectly valid if Darwinism were regarded simply as a scientific investigation. But it is under consideration now on very different rounds. Whatever Mr.

Darwin's own views may be, the theory is brought forward by others, not as a mere interesting speculation, but as antagonistic to a record whose authority is attested by evidence of the very highest cla.s.s. It claims to discredit that record, and to be received as a subst.i.tute for it. But that record, however it may be interpreted, does give us adequate causes for all that it professes to account for, in the will and operation of an Almighty Creator. The theory, therefore, which professes to supplant it, must at least stand upon an equal ground--it must give an adequate account of everything. There must be no unverified laws.

To fall back upon such laws is in reality to fall back on the working of that very power whose operation is formally denied.

[Footnote: See Foster's Essays, Essay i. Letter 5.]

The next point to be noticed is a great confusion between a.s.sumptions and proved facts. This is especially prominent in that part of his last work which is devoted to s.e.xual selection. Thus, in one case it is taken for granted, that various characteristics of the males "serve only to allure or excite the female."

[Footnote: Descent of Man, vol. i. p. 258.] "Hence" (because brilliant colours of insects have probably not been acquired FOR THE PURPOSE of protection), "I am led to suppose that the females generally prefer, or are most excited by the more brilliant males." [Footnote: Ibid. p. 399.] "Nevertheless, when we see many males pursuing the same female, we can hardly believe that the pairing is left to blind chance; that the female exerts no choice, and is not influenced by the gorgeous colours, or other ornaments with which the male alone is decorated" [Footnote: Descent of Man, vol. i p. 421.] Such sentences are of continual occurrence, and do duty in the argument as if they expressed ascertained facts. And not only this, but in the very part of the work which is devoted to establishing the adequacy of s.e.xual selection to produce certain effects, that adequacy is a.s.sumed from the very beginning.

Thus, we read, "That these characters are the result of s.e.xual selection is clear," [Footnote: Ibid. p. 258.] before we have got six pages into an argument which occupies a volume and a half.

This is surely a strong instance of what is commonly called "begging the question." Another instance of confusion of ideas is to be found in the a.s.sumption of design which occasionally occurs.

Thus, we read, "In some other remarkable cases beauty has been gained for the sake of protection, through the imitation of other beautiful species." [Footnote: Ibid. p. 393.] "From these considerations Mr. Bates inferred, that the b.u.t.terflies which imitate the protected species, had acquired their present marvellously deceptive appearance through variation and natural selection, in order to be mistaken for the protected kinds."

[Footnote: Descent of Man, vol. i. p. 411.] In these cases there is an a.s.sumption of purpose and design, which, necessarily implies a designer, just as law, treated as an efficient cause, implies a law-giver. It may indeed be that this is only an inaccurate way of expressing something else; but then, such modes of expression are usually the result of a want of clear perception of the ideas to be expressed; and, in this case, such expressions must diminish the weight to be a.s.signed to Mr. Darwin's judgment.

We come now to the consideration of the first of Mr. Darwin's supposed agencies--"Natural Selection," or, "Survival of the fittest." The results produced by this process must be ascribed to one of two causes: either they are the work of a Superintending Providence, watching over and directing every separate detail; or they are the result of pure chance and accident. There is nothing intermediate between these two causes. Natural law--apart from design and a designer--is, as we have seen, a nonent.i.ty--a mere expression of observed facts, for which it can give no account whatever. Mr. Darwin's argument is expressly directed to exclude the interference of a superintending Providence. Chance is the only cause which he can bring forward. The very first question, then, which arises is, What is there upon which chance may operate? What are the conditions from which the probabilities may be calculated? Mr. Darwin a.s.sumes, and no doubt correctly, that minute variations are continually taking place. But as these variations are the result of accident [Footnote: If they are not the result of accident, we again see design and need a designer.]

they will take place in various directions; some of them will have a beneficial, some of them a noxious tendency. As, moreover, they are supposed to be very small at each step, the difference of advantage in the case of different individuals must be also very small, and will not be likely to produce any considerable difference in the chances of pairing. But in order that any variation may be perpetuated and increased, the pairing of similarly affected individuals is necessary. Parents, in which the variations took opposite directions, would probably have offspring of the normal type, the opposite variations neutralizing each other. And this must be repeated again and again; and with every repet.i.tion of the process required, the probabilities against it would rapidly increase. Thus, supposing that in the first generation the proportion of favourable conditions were such, that of those animals that paired there were four of each s.e.x that had them to three that wanted them, the chances that any given pair were alike in possessing them would be represented by the product 4/7 x 4/7, or 16/49. Hence, the chances would be rather more than two to one against it. In the next generation it would be 256/2401, or more than eight to one, and so on. [Footnote: This is given merely as an ill.u.s.tration of the nature of the calculation.

In any actual case the conditions would be infinitely more complex, but the calculation, if it could be made at all, must be made on this principle.]

But next, we have not to do with one series of changes only, but with a vast number of different series going on in different directions, if we are to have a large variety of animals produced from a common stock. All the probabilities against the separate variations must be combined, not by addition, but by multiplication, so that the probabilities against the production of all these separate forms become enormous.

Against all this improbability Mr. Darwin brings forward the supposed advantages which these variations give to their possessors. But here again a new element is introduced into the calculation. It is a.s.sumed, in the very statement of the question, that the process of adaptation has already taken place; the original stock must have been adapted to the circ.u.mstances under which they existed, or in their case the whole theory fails. If, then, a fresh adaptation is wanted, it must be because a change in external circ.u.mstances must have taken place. In order that a new variety may be established there must be a concurrence between the change of external circ.u.mstances and the change in the animals.

Here we get a new, and a large factor for our multiplication.

This argument may be, perhaps, made clearer by an ill.u.s.tration.

Mr. Darwin has written a very interesting book on the fertilization of orchids by means of insects. According to his view all insects are descended from one common type, and all orchids are also descended from one parent; but we meet with insects and orchids in pairs, each perfectly adapted to the other.

We will suppose that a change takes place in a particular orchid, that the nectary recedes to a greater distance from the point to which the insect can penetrate, and so an advantage is given to those insects in which the haustellum is of a length above the average. This may have a slight tendency to increase the number of such insects; but then it will have an opposite tendency in the case of the orchid. It cannot, of course, be supposed that the variation, which is only partial in the insect, is universal in the plant. The unchanged insects will therefore be confined to the unchanged flowers, while the changed insects will be indifferent on the subject, as they will be able to reach the nectary in any case. Hence, an advantage will be given to the unchanged flower, which will be more likely to be fertilized, and the two lines of variation will move in opposite directions.

But next, the variation in the insects and the flowers must take place at the same time and the same place, or no result will follow to the insect, while the new variety of orchid must perish for want of an insect to fertilize it. It is this which makes the supposition of unlimited time almost useless, because just in proportion as the time is increased the probability of two independent events happening simultaneously is diminished.

But even supposing this difficulty out of the way, we meet with an immediate repet.i.tion of it. The insect derives an advantage from its increased haustellum, but what advantage does the plant derive from its retiring nectary? How does that help it in the "struggle of life?" But if it produces no beneficial result, the variation according to the theory must drop. Hence we should arrive at an insect suited for a new form of the flower, but no flower suited to the new form of the insect.

If, then, we reject the idea of superintendence and design, we have on the one hand an enormous antecedent improbability, while on the other hand we have only a very small power by which a direction may be given to the course of events, since by the hypothesis in any one generation the change, and consequently the superior advantage, is exceedingly small, and there is a strong tendency in related changes, as in the case of the orchid and insect, to move in opposite directions.

But next, in the varieties of animals with which we are acquainted, there is a certain connexion between the differences of independent organs, for which this theory does not help us to account. Thus, for instance, according to this theory the canine and the feline races are descended from a common ancestor. But there are several points of difference between a cat and a dog.

There are the differences in the form of jaws, in the dent.i.tion; in the muscles by which the jaws are moved, and in the feet and claws. All animals of the cat tribe agree in all these respects, so do all animals of the dog tribe. We never find a cat's head combined with the feet of a dog. Why is this? Mr. Darwin attempts to account for it by his supposed law of "correlation of growth,"

but, as has been already shown, any such law, being by Mr.

Darwin's definition the observed sequence of events and nothing more, is utterly useless, when it is brought forward as a cause for those events. On this point the theory completely breaks down.

3. The theory does not account for any changes which are not immediately beneficial. [Footnote: In the "Origin of Species" (Ed.

1872) Mr. Darwin makes an admission which is virtually a giving-up of his whole theory. He says, "In many other cases modifications are probably the direct result of the laws of variation or of growth, independently of any good having been thus gained; but even such structures have often, as we may feel a.s.sured, been subsequently taken advantage of," pp. 165, 166. Here, then, we have a preparation for future circ.u.mstances, which surely implies design.] If any rudimentary advance is made in the organism, if, for instance, the rudiments of a new bone, or joint, or organ of sense are developed, the nascent organ must, according to the hypothesis of minute changes, be useless in the first instance.

Hence it would confer no advantage in the struggle of life; there would be no tendency towards its preservation and growth. This becomes a very important consideration, when certain important differences in animal structure and habits are to be accounted for. How, for instance, could the mammary glands be developed in oviparous creatures? Mr. Darwin regards them as originating in cutaneous glands, developed in the pouch of the marsupials. But his grounds for this statement are very meagre. To a great extent they rest on what an American Naturalist "believes he has seen;"

and besides, the ornithorhyncus, which has no pouch, and which is lower in the scale of life than the marsupials, by Mr. Darwin's own admission (O. S., p. 190), possesses the glands. Mr. Mivart's question (Darwin, O. S., p. 189) is a very pertinent one.

Another point which this view fails to explain, is the determination of the line of development in particular directions at different periods. At one time it is most marked in fishes, at another in reptiles, at another in mammals. How is this to be accounted for?

4. The experience of cattle-breeders does not warrant the a.s.sumption that the principle of natural selection has more than a limited operation. No case has as yet been brought forward in which varieties have been produced which were not capable of interbreeding. Apart from their experience there is not a particle of evidence in favour of the a.s.sertion that races which cannot be made to breed together can be descended from a common stock. The unlimited application of this principle is therefore a pure a.s.sumption.

5. To this must be added the circ.u.mstance that no authenticated instance of variation by natural selection can be brought forward.

It is true that this is not a very important argument, because our knowledge of those cla.s.ses of animals in which natural selection could act is even now very incomplete; and our knowledge of their past history is still more limited, so that we are not in a condition to prove a negative. But in such a case as this the onus of proof should surely lie on the other side. It is for those who would a.s.sert the theory to bring forward positive proof of it.

There is, however, one point in Mr. Darwin's view of domesticated animals which tells against his theory. The cat remains unchanged, because from its vagrant habits man has no control over its pairing [Footnote: Darwin's "Animals and Plants," vol. ii. p.

236.]. Now considering the variety of conditions under which cats exist, here is surely a great opening for natural selection. But it has produced no results.

We come now to the theory of s.e.xual Selection, which is to account for those peculiarities and distinctions which can have no beneficial effect in the struggle of life, and which are accounted for on the supposition that they render their possessors more agreeable to the opposite s.e.x, and so facilitate pairing, so that those animals which possess them in a remarkable degree would have the greatest chance of continuing their race. The case on which Mr. Darwin mainly rests his argument is that of birds, in which the males are frequently distinguished by exquisite colours and very graceful markings, and in which also the proceedings of the s.e.xes can, in many cases, be more easily watched.

It is in maintaining this theory that Mr. Darwin has such frequent recourse to what may be called the "argumentum ad ignorantiam."

"If such and such organs or ornaments were not designed for this or that particular object, then we do not know of what use they are." [Footnote: For instance, Descent of Man, vol. ii. pp. 284.

399.] This maybe very true, but it proves nothing, unless we a.s.sume that we are or ought to be acquainted with, the use and object of everything in nature. And it involves another and a very wide question. There are certain tastes which seem to be inherent in our nature, and there are certain external objects which afford gratification to those tastes. Must we view this coincidence as merely accidental? or is it a part of the design of the world that it should minister not only to our needs, but also to our enjoyments? Mr. Darwin does not reject the idea of an Author and Designer of Nature, is he then prepared to a.s.sert that beauty did not form a part of the design as well as utility? [Footnote: In the "Origin of Species," p 159, Mr. Darwin does seem to a.s.sert this; but he says in conclusion, "How the sense of beauty in its simplest form--that is, the reception of a peculiar kind of pleasure from certain colours, forms, and sounds--was first developed in the mind of man and of the lower animals is a very obscure subject," p. 162. To Mr. Darwin, with his present views, it may well be obscure; but it presents no obscurity at all to those who believe that the universe in all its details was designed, and its formation superintended, by a loving Father, whose will was that it should not only supply the needs, but also minister to the enjoyment of all His creatures, nor to those who in every form of beauty, physical, intellectual, or moral, behold a far-off reflexion of the glory of the Invisible Creator.] If he is not prepared to a.s.sert this, he must admit the possibility that many things exist whose sole object is to minister to that sense of beauty which is probably possessed by other beings besides ourselves.

Mr. Darwin admits that many other causes, beside the supposed preference on the part of one s.e.x for certain material adornments possessed by the other, influence the pairing of animals. In a very large number of cases the female is quite pa.s.sive in the matter. The question is decided by a battle between the males, and the female seems, as a matter of course, to become the mate of the conqueror. In many other cases pairing seems to be the result of accident; the two s.e.xes pair as they happen to meet each other.

The great points on which Mr. Darwin rests his argument are that in some cases, on the approach of breeding-time, certain ornamental appendages become more highly developed or more brilliantly coloured, [Footnote: Descent of Man, vol. ii. p. 80.]

and that in many cases the males, when courting the females, are observed to display their ornaments before them. [Footnote: Ibid.

vol. ii. p. 86, et seq.] but then there are other facts, which Mr.

Darwin. also notices, which detract more than he seems willing to allow, from the relevancy of these facts. The development of ornaments at breeding-time sometimes takes place in both s.e.xes, indicating some latent connexion with the reproductive organs; thus the comb of the domestic hen becomes a bright red, as well as that of the c.o.c.k. It would appear then that the object of the change is not to render the c.o.c.k more attractive to the hens, for how could it serve the hens (if the choice lies with them) to be made more attractive to the c.o.c.ks? Then again an old hen who is past laying, often a.s.sumes, to a considerable extent, the plumage of the c.o.c.k. When these ornaments are the exclusive possession of the male, they are often displayed for other purposes than the gratification of the female. The possessors seem to be conscious of their beauty, and to take a pleasure in displaying it to any spectators.

Very great beauty and brilliancy of colour is often found in cases in which it can have nothing whatever to do with the relation between the s.e.xes. Thus, a vast number of caterpillars are remarkable for their beauty; but in their immature state it can have no relation to s.e.xual selection; and if it may, or rather must, have a different object in one case, what ground have we for a.s.suming that it may not have a different object in the other?

Again, we are not in a position to form any opinion as to the causes which really influence the pairing of animals when choice is exercised. We have no certain knowledge upon the important question whether the ideal of beauty, if possessed by the lower animals at all, is in all, or even in many cases, in accordance with our own. We, for instance, admire a male humming-bird; what certainty have we that he is equally beautiful in the eyes of his mate? In cases where we have reason to believe that deliberate selection has taken place, we do not know that that selection was influenced by only one condition--that of beauty. There may have been a thousand causes at work of which we know nothing. Mr.

Darwin brings forward an instance in which the owner of a number of peahens wished them to breed with a peac.o.c.k of a particular variety, while they showed a deliberate preference for another bird; and he supposes that their preference was decided by the plumage. But there might have been another cause--at least the circ.u.mstances as related by him seem to suggest it--which would give a very different turn to the affair. The favoured peac.o.c.k, spoken of as "old," [Footnote: Descent of Man, vol. ii. p. 119.]

was probably an old friend of the hens, while his unsuccessful rival seems to have been a new introduction. The preference shown by the hens would in this case be fully accounted for, without supposing them to have exhibited any choice in the matter of plumage.

Then there are a vast number of peculiarities which are certainly not ornamental in our eyes, but which are confined to the male s.e.x. They are, so far as we can tell, of no service whatever in the struggle of life. With reference to these Mr. Darwin's argument seems to be this,--"They can serve no other purpose with which we are acquainted, therefore they must be attractive to the female--therefore they must be acquired by s.e.xual selection." Such arguments as these cannot carry much weight. [Footnote: Descent of Man, vol ii p 284.]

On the whole, we can hardly come to any other conclusion than that the theory of s.e.xual selection is not proved. In many cases it is known that such selection is not the result of choice; in other cases, where choice seems probable, we have no ground for believing that external appearance is the sole ground of that choice. It may exercise some influence, but that is all. Even if admitted, there are many things which cannot be accounted for by it without very extravagant a.s.sumptions. It cannot then be admitted as covering the large cla.s.ses of phenomena left unaccounted for by the theory of natural selection.

So far as the lower animals are concerned, the results to which an examination of Mr. Darwin's views has led us may be summed up in the following propositions:--

1. That the two causes, natural and s.e.xual selection, have probably exercised some influence in the modification of animal forms; but that the laws of probability preclude our entertaining the belief that these causes can have had, by themselves, and apart from a superintending power, anything beyond a very limited operation.

2. That in cases where there have been related changes in different parts of the same organism, or in different organisms, the inadequacy of these two causes is virtually admitted by the introduction of certain supposed laws; and that these laws, being defined by Mr. Darwin to be no more than "the ascertained sequence of events," cannot be regarded as efficient causes, and so cannot supply the defect.

3. That there are particular points in the chain of life, in which the transition from one form to another is so great, and so incapable of graduation, that it is impossible to suppose that these two causes can have been adequate to produce it. Of this a notable instance is to be found in the transition from oviparous animals to the mammalia.