The doctrine of evolution according to Herbert Spencer further considered.

In the last preceding chapter, I have examined Mr. Spencer's chief objection to the doctrine of special creations when considered in its general aspects. I now advance to the general aspects of the evolution hypothesis as applied by this philosopher to the animal kingdom. I have already suggested the appropriate answer to the claim that the derivation of the evolution hypothesis is favorable because it has originated "among the most instructed class and in these better-instructed times," and that the derivation of the other hypothesis is unfavorable because "it originated in times of profound ignorance." On this point it is unnecessary to say more. But there is a supposed "kindred antithesis" between "the two families of beliefs" to which these two hypotheses are said respectively to belong; one of which families "has been dying out," while the other family "has been multiplying." This brings into view the peculiar philosophical system of Mr. Spencer, by which he maintains "the unity of Nature," or the prevalence of a universal law of evolution, as the law which is to be discerned in remote fields of inquiry, and which "will presently be recognized as the law of the phenomena which we are here considering," namely, the phenomena of animal life. "The discovery that evolution has gone on, and is going on, in so many departments of Nature, becomes a reason for believing that there is no department of Nature in which it does not go on."[69]

In considering this mode of generalization it is important to distinguish between the phenomena that are observable in those departments of Nature which include only dead or inanimate matter, and the phenomena that are peculiar to matter organized into living beings. Again: it is important to distinguish between phenomena which have been influenced by human agencies and those which can not have been affected by the power of man. Another distinction of the greatest consequence is that which divides the phenomena in question according to their relation to a moral purpose. In one class of phenomena, a moral purpose may be plainly discovered as the purpose of an intelligent causing power, which has chosen a particular means for the accomplishment of an end. In another class of phenomena, a moral purpose may not be discoverable as the end for which the existing arrangement of things was specially designed, and to which that arrangement was an indispensable means. By classifying the departments of Nature and observing their phenomena with these discriminations, we shall be able to judge of the value of Mr. Spencer's philosophical system when applied to the animal kingdom.

In grouping the departments and their respective phenomena as departments in which the law of evolution has obtained, and in drawing from them the sweeping deduction that there is no department in which this law has not obtained as the causa causans, Mr. Spencer does not appear to have made these necessary discriminations. He specifies the following remote fields of inquiry, in which he maintains that this law of evolution is now admitted to be the solution of the phenomena that lie in those respective fields: First, the solar system, which, as he asserts, astronomers now consider has been gradually evolved out of diffused matter.[70] Second, geological discoveries, which show that the earth has reached its present varied structure through a process of evolution. Third, society, which has progressed through a corresponding process of gradual development. "Constitutions are not made, but grow," is said to be now a recognized truth among "philosophical politicians," and a part of the more general truth that "societies are not made, but grow." Fourth, languages, which, we are told, are now believed not to have been artificially or supernaturally formed, but to have been developed. Finally, the histories of religions, philosophy, science, the fine arts, and the industrial arts, show, it is said, development "through as unobtrusive changes as those which the mind of a child passes on its way to maturity."[71]

It is obvious that in some of these departments neither human agency nor the human will and choice can have had any influence in producing the phenomena, while in some of them human agency, will, and choice have had a vast influence in making the phenomena what they are. That political constitutions or social institutions are not made, but grow, is a dogma that is by no means universally true, however wise it may sound, or with whatever confidence in a paradox it may be asserted by "some political philosophers." While past events and present exigencies may have largely shaped some political constitutions, we know that others have been deliberately modified by a choice that has had more or less of a free scope, and that sometimes this has amounted to an arbitrary decision. Languages may or may not have been a direct and supernatural gift from Heaven, but we know that their structure has been powerfully influenced by human agencies, when they have come to be written expressions of thought; for they have then received expansion by the actual coinage of new words, as well as by new meanings of old words; and even when they were in the first stages of a spoken tongue, inflections that were purely arbitrary have been introduced. So it has been with systems of religion, philosophy, the fine arts, the mechanic arts, legislation, and jurisprudence. While in all these departments changes have been going on, which upon a superficial view appear to indicate a kind of spontaneous development, when they are analyzed they are seen to have been wholly caused, or more or less influenced, by the genius, the thought, the discoveries, the exertions, and the acts of particular individuals who have had the force to impress themselves upon the age, and thus to make new systems, new beliefs, new products, new rules of social or political life, new tastes, and new habits of thinking and acting.

Again: in some of the various orders of phenomena which are found in these different departments, there is discernible a distinct moral purpose in the shape which they have been made to assume, and in others of them there is no moral purpose discoverable, which we can say required the employment of the particular means to effect the end. Thus, astronomers can not assign a moral purpose for which the distribution of the fixed stars was made to be what it is, and which purpose could not have been answered by some other arrangement. At the same time, it is easy to see that the solar system was arranged with reference to the law of universal gravitation, which made this arrangement of the different bodies essential to the harmonious working of a great and complex piece of mechanism. The present formation of the earth may have resulted just as geologists think it has, and yet they can not say that there was no moral purpose in the division of the exterior surface of our globe into land and water, seas, continents, mountains, etc. These are departments of Nature in which man has had no influence in producing the phenomena. When we turn to those departments in which man is placed as an actor, we often find an adjustment of means to an end that is so comprehensive, as well as so plain, that we may justly conclude it to have been chosen by the creating power, with the express intent that human agency should be the means by which certain effects are to be produced. For example: man is eminently a social animal. Human society is a result of his strong social propensities. He is placed in it as an actor; and in this arrangement there is discoverable a moral purpose so plain that we may rightfully regard the social phenomena of mutual protection and improvement as proofs that society was ordained as the sphere of man's highest development on earth.

So that, in reasoning about the phenomena of any of the departments of Nature as affording indications of the so-called universal law of evolution, we must not forget the distinction between organized inanimate and organized animated matter; or the distinction between those departments in which human will or choice, or the human intellect, has had no influence in shaping the phenomena, and those in which they have had great influence; or the distinction between phenomena in which a special moral purpose can be and those in which it can not be discovered, as the reason for the existing order of things. It is especially hazardous to argue that because a spontaneous development, or a gradual evolution, can be traced in some of the phenomena of inanimate matter, it therefore must obtain in the animal kingdom. It is alike hazardous to argue, because there has been what is called evolution in some departments of Nature over which man has had no control, that the same law obtains in other departments over which he has also had no control, or those in which he has had a large control.

The bearing of these discriminations upon the supposed universality of the law of evolution may now be seen if we attend to the further inquiry whether that law obtains throughout all the phenomena of any one department of Nature as the sole cause of the phenomena in that department. Take again, for example, the solar system. Suppose it to be true that the bodies which compose it, the sun and the planetary spheres, were gradually evolved out of diffused matter. Does it necessarily follow that their existing arrangements and mutual relations were not specially designed? That their orbits, their revolutions, their distances from each other, were not specially planned? That they were not hung in their respective positions with an intentional adjustment to the great force of gravitation that was prevailing throughout the universe? Must we suppose that all this part of the whole phenomena of the solar system resulted from the operation of an ungoverned evolution, because the bodies themselves may have been gradually formed out of diffused matter into their present condition without being spoken at once into that condition by the fiat of the Almighty? We can certainly see that the existing arrangements must have been intentional; and, if intentional, the intention must have taken effect in the production of the phenomena exhibited by the arrangement, as any design takes effect in the production of the phenomena which are open to our observation. The moral purpose evinced by one part of this arrangement, the alternation of day and night upon the earth, for example, might have been effected by some other means than the means which now produce it. But there is the strongest evidence that a certain means was chosen and intentionally put into operation; and although we can not tell why that means was preferred, the fact that it was both designed and preferred makes it a special creation. To suppose that it was left to be worked out by a process such as the hypothesis of evolution assumes, by the gradual, fortuitous, and ungoverned operation of infinitely slow-moving causes, which might have made the adjustments very different from what they are, is to deprive it of the element of intentional preference that is proved by its existence. The hypothesis of evolution, when applied to all the phenomena of the solar system, relegates one great branch of those phenomena to a realm from which all special purposes and all direct design are absent, and confines the explanation of the phenomena to the operation of causes that might have brought about very different arrangements. That this supposed process of evolution has, in fact, been followed by the existing arrangements of the solar system, does not prove, or tend to prove, that the existing arrangements are solely due to the supposed method of their production; for we can not leave out the element of some design, and if there was a design, the very nature of the system required that the design should be executed by a special creation of a plan for the mutual relations of the bodies composing it. The bodies themselves might have been gradually formed out of diffused matter, floating loosely in the realms of space. The relations of the bodies to each other required the act of an intelligent will, in the direct formation of an intentional plan; and that act was an act of special creation in the same sense in which the structural plan of a species of animal was a special creation.

Here, then, is one department of Nature in which it is not necessary and not philosophical to assume that the law of so-called evolution has been the universal law to which all the phenomena of that department are to be attributed. If we follow out the same inquiry in other departments of Nature remote from the animal kingdom, we shall find reason to adopt the same conclusion in respect to their phenomena. Thus, let us for a moment contemplate another of the departments in which inanimate matter is the subject of observation, and in which human will or intelligence has had no agency in producing the phenomena, namely, the formation of the present structure of the earth as it is described by geologists. This is a department in which the hypothesis of evolution finds perhaps its stronghold. Yet it is necessary even here to recognize an intentional plan and direct design in some part of the phenomena. Let us suppose that during the period required by any of the speculations of geologists, however long, a mass of matter was gathered in an unformed condition, and gradually shaped into the present condition of the earth by the action of its constituent elements upon each other, influenced by the laws of mechanical forces, of chemical combinations, of light and heat, and of whatever physical agencies were made to operate in the process of evolving the mass into the condition in which it has been known to us for a certain time. Is it a rational conclusion that the intelligent power which put these forces in operation—an hypothesis with which we must begin to reason, or leave the origin of both matter and forces to blind chance—did not guide their operation at all to the intentional production of the results which we see? The results disclose some manifest purposes; and although these purposes, or others equally beneficent, might have been accomplished by different arrangements, we can see that they have been effected by a certain arrangement of a specific character. The results have been continents, seas, mountains, rivers, lakes, formation and distribution of minerals, growth of forests, and an almost innumerable, and certainly a very varied, catalogue of phenomena, physical formations, and adaptations. All these varied results disclose a plan by which this earth became a marvelously convenient abode for the living creatures that have inhabited or still inhabit it, especially for man. The formation of this plan was an intelligent act, if we suppose that any intelligent being projected the original gathering of the crude primordial matter and subjected it to the operation of the forces employed to shape it into its present condition. This plan was an act of special creation, in the same sense in which the plan of a particular animal organism may have been a special creation. While, therefore, a process which may be called evolution may have operated as the agency through which the earth has reached its present physical condition, the plan of that condition was certainly not formed by any such process; for it was, if it was the product of anything, the product of an intelligent will operating in the production of preconceived results by the exercise of superhuman and infinite wisdom and foresight.

When we turn to a department in which human influence has largely or wholly shaped the phenomena, we find numerous special creations that are not attributable to the operation of any law of development or evolution such as is supposed to have led to the production of one species of animal out of another, or out of several previous species. In short, a survey of all the departments of Nature leads to the conclusion that while there may be phenomena which are properly traceable to the operation of the forces of Nature, or to fixed general systems of production, there is another very large class of the phenomena which owe their existence to special acts of an intelligent will, finite or infinite, human or divine, according as their production required superhuman power or admitted of the efficacy of man's intervention.

The way is now somewhat cleared for an examination of Mr. Spencer's application of the law of evolution to the gradual formation of different species of animals out of one or more previous species, without any act of special creation intervening anywhere in the series. We have seen that this alleged law is not of universal force as the cause of all the phenomena in all the departments of Nature. When we come to apply it as the hypothesis which is to account for the existence of different species of animals of very different types, we must remember that we are dealing with organisms endowed with life, and, although we can not sufficiently explain what life is, we know that animated organisms are brought into being by systems of production that are widely different from the modes in which inanimate matter may have been or has been made to assume its existing forms. Bearing this in mind, we come to the arguments and proofs by which Mr. Spencer maintains the immense superiority of the evolution hypothesis over that of special creations, in reference to the animal kingdom. It must be remembered that this is a department in which man can have had no agency in producing the phenomena, for whatever may have been the slight variations produced by human interference with the breeding of animals domesticated from their wild condition, we must investigate the origin of species as if there had never been any human intervention in the crossing of breeds, because that origin is to be looked for in a sphere entirely removed from all human interference. Man himself is included in the investigation, and we must make that investigation in reference to a time when he did not exist, or when he did not exist as we now know him.

One of the favorite methods of Mr. Spencer consists in arraying difficulties for the believers in special creations, which, he argues, can not be encountered by their hypothesis, and then arguing that there are no difficulties in the way of the hypothesis of evolution. His position shall be stated with all the strength that he gives to it, and with all the care that I can bestow upon its treatment. He puts the argument thus: In the animal kingdom individuals come into being by a process of generation—that is to say, they arise out of other individuals of the same species. If we contemplate the individuals of any species, we find an evolution repeated in every one of them by a uniform process of development, which, in a short space of time, produces a series of astonishing changes. The seed becomes a tree, and the tree differs from the seed immeasurably in bulk, structure, color, form, specific gravity, and chemical composition; so that no visible resemblance can be pointed out between them. The small, semi-transparent gelatinous spherule constituting the human ovum becomes the newly-born child; and this human infant "is so complex in its structure that a cyclopÆdia is needed to describe its constituent parts. The germinal vesicle is so simple that it may be defined in a line. Nevertheless, a few months suffice to develop the one out of the other, and that, too, by a series of modifications so small that were the embryo examined, at successive minutes, even a microscope would with difficulty disclose any sensible changes. Aided by such facts, the conception of general evolution may be rendered as definite a conception as any of our complex conceptions can be rendered. If, instead of the successive minutes of a child's foetal life, we take successive generations of creatures, if we regard the successive generations as differing from each other no more than the foetus did in successive minutes, our imaginations must indeed be feeble if we fail to realize in thought the evolution of the most complex organism out of the simplest. If a single cell, under appropriate conditions, becomes a man in the space of a few years, there can surely be no difficulty in understanding how, under appropriate conditions, a cell may, in the course of untold millions of years, give origin to the human race."[72]

Here, then, we have a comparison between what takes place in the development of the individual animal in the space of a few years, and what may be supposed to take place in the successive generations of different creatures through untold millions of years. We turn then to the proof, direct or indirect, that races of entirely distinct organisms have resulted from antecedent races by gradual transformation. Direct proof sufficient to establish the progressive modifications of antecedent races into other races is not claimed to exist; yet it is claimed that there are numerous facts of the order required by the hypothesis which warrant our acceptance of it. These facts are the alterations of structure which take place in successive generations of the same species, amounting, in the course of several generations of the same race, to additions and suppressions of parts. These changes among the individuals of the same race, comprehended in what is scientifically called "heredity" and "variation," are exhibited by the transmission of ancestral peculiarities of structure, by their occasional suppression in some individuals of the race and their reappearance in others, and by a difference in the relative sizes of parts. These variations, arising in successive short intervals of time, are said to be quite as marked as those which arise in a developing embryo, and, in fact, they are said to be often much more marked. "The structural modifications proved to have taken place since organisms have been observed is not less than the hypothesis demands—bears as great a ratio to this brief period as the total amount of structural change seen in the evolution of a complex organism out of a simple germ bears to the vast period during which living forms have existed on earth."[73]

The difficulty that is thus prepared for the hypothesis of the special creation of species may now be stated. There is a professed conception of the ultimate power which is manifested to us through phenomena. That conception implies omnipotence and omniscience, and it therefore implies regularity of method, because uniformity of method is a mark of strength, whereas irregularity of method is a mark of weakness. "A persistent process, adapted to all contingencies, implies greater skill in the achievement of an end than its achievement by the process of meeting the contingencies as they severally arise." And, therefore, those who adopt the notion of the special creation of species do, it is said, in truth impair the professed character of the power to which they assume that the phenomena of the existence of species are to be referred, whereas the hypothesis of the evolution of species out of other species is much more consistent with the professed conception of the ultimate power.

In this claim of superiority for the evolution hypothesis, the learned philosopher seems to have been almost oblivious of the fact that he was dealing with animal organisms in two aspects: first, in regard to the method by which individuals of the same species come into existence; and, secondly, in regard to the method by which different species have come into existence. In the first case, regularity of method is evinced by the establishment of a uniform process of procreation and gestation. This process, while retaining throughout the different classes of animals one fundamental and characteristic method, namely, the union of the sexes, is widely varied in respect to the time of gestation, the foetal development, and the nourishment of the young before and after birth. There is no difficulty whatever in discovering the great reason for which this system of the reproduction of individuals was established. The tie that it makes between parents and offspring, and more especially the tie between the female parent and the offspring, was obviously one grand end for which this system of giving existence to individuals was adopted; and although the instinct which arises out of it is in some species feeble and almost inactive, it rises higher and higher in its power and its manifestations in proportion as the animals rise in the scale of being, until in man it exhibits its greatest force and its most various effects, producing at last pride of ancestry, and affecting in various ways the social and even the political condition of mankind. But how can any corresponding connection between one race of animals and another, or between antecedent and subsequent species, be imagined? The sexual impulse implanted in animals leads to the production of offspring of the same race. The desire for offspring keeps up the perpetual succession of individuals, and love of the offspring insures the protection of the newly born by the most powerful of impulses. But what can be imagined as an analogous impulse, appetite, or propensity which should lead one species to strive after the production of another species? Is it said that the different species are evolved out of one another by a process in which the conscious desires, the efforts, the aspirations of the preceding races play no part? This is certainly true, if there was ever any such process as the evolution of species out of species; and it follows that, in respect to one great moral purpose of a process, there is no analogy to be derived from the regularity and uniformity of the process by which individuals of the same species are multiplied. Moreover, in regard to the latter process, we know that a barrier has been set to its operation; for Nature does not now admit of the sexual union between animals of entirely distinct species, and we have no reason to believe that it ever did admit of it at any period in the geological history of the earth.

Still further: In what sense are special creations "irregularities of method"? In what sense are they "contingencies"? And if they are "contingencies," how does it imply less skill to suppose that they have been met as they have severally arisen, than would be implied by supposing that they have been achieved by a uniform process adapted to all contingencies? This notion that something is derogated from the idea of omnipotence and omniscience by the hypothesis that such a power has acted by special exercises of its creating faculty in the production of different orders of beings as completed and final types, instead of allowing or causing them to be successively evolved out of each other by gradual derivations, is neither logical nor philosophical. In no proper sense is a method of action an irregular method unless it was imposed upon the actor by some antecedent necessity, which compelled him to apply a method which was made uniform in one case to another case in which the same kind of uniformity would not be indispensable. The uniformity of the process by which individuals of the same species are multiplied is a uniformity for that particular end. The regularity in that case is a regularity that has its special objects to accomplish. The uniformity and regularity of a different method of causing different types of organisms to exist, so long as the object is always effected in the same way, is just as truly a regularity and uniformity for that case, and just as completely fulfills the idea of infinite skill. That such creations are specially made, that they are independently made, and that each is made for a distinct purpose and also for the complex purposes of a varied class of organisms, does not render them contingencies arising at random, or make the method of meeting them an occasional, irregular, spasmodic device for encountering something unforeseen and unexpected. The very purposes for which the distinct organisms exist—purposes that are apparent on a comprehensive survey of their various structures and modes of life—and the fact that they have come into existence by some process that was for the production of the ends a uniform and regular one, whether that process was special creation or evolution, render the two methods of action equally consistent with the professed conception of the ultimate power. On the hypothesis of special creations so many different types of organism as the Creator has seen fit to create have been made by the exercise of a power remaining uniformly of the same infinite nature, but varying the products at will for the purposes of infinite wisdom.

What, again, does the learned author mean by meeting "contingencies" "as they have severally arisen"? This suggestion of a difficulty for the believers in special creations seems to imply that the distinct types of animal organisms arose somehow as necessities outside of the divine will, and that the Almighty artificer had to devise occasional methods of meeting successive demands which he did not create. The hypothesis of special creations does not drive its believers into any such implications. The several distinct types of animal organisms are supposed to have arisen in the divine mind as types which the Almighty saw fit to create for certain purposes, and to have been severally fashioned as types by his infinite power. They are in no sense "contingencies" which he had to meet as occasions arising outside of his infinite will. A human artificer has conceived and executed upon a novel plan a machine that is distinguishable from all other machines. He did not create the demand for that machine; the demand has grown out of the wants of society; and the artificer has met the demand by his genius and his mechanical skill, which have effected a marked improvement in the condition of society. In one sense, therefore, he has met a "contingency," because he has met a demand. But the infinite Creator, upon the hypothesis of his existence and attributes, does not meet an external demand; there is no demand upon him; he creates the occasion; he makes the different organisms to effectuate the infinite purposes which he also creates; the want and the means of satisfying the want alike arise in the infinite wisdom and will. Such is the hypothesis. We may now, therefore, pursue in some further detail the argument which maintains that this hypothesis is of far inferior strength to that of evolution, as the method in which the Almighty power has acted in the production of different animal organisms.

First we have the analogy that is supposed to be afforded by what takes place in the development of a single cell into a man in the space of a few years, and an alleged correspondence of development by which a single cell, in the course of untold millions of years, has given origin to the human race. Granting any difference of time which this comparison calls for, and substituting in place of the successive moments or years of an individual life, from the formation of the ovum to the fully developed animal, the successive generations of any imaginable series of animals, the question is not merely what we can definitely conceive, or how successfully we can construct a theory. It is whether the supposed analogy will hold; whether we can find that in the two cases development takes place in the same way or in a way that is so nearly alike in the two cases as to warrant us in reasoning from the one to the other. In the case of the development of the single cell into the mature animal, although we can not, either before or after birth, detect the changes that are taking place from minute to minute, the infinitesimal accretions or losses, we know that there is a perpetual and unbroken connection of life maintained from the moment when the foetus is formed to the moment when the mature animal stands before us. Break this connection anywhere in the process of development, and life is destroyed; the development is at once arrested. It is this connection that constitutes, as I presume, what the learned author calls the "appropriate conditions," in the case of the production of the individual animal; it is, at all events, the one grand and indispensable condition to the development of the cell into the foetus, of the foetus into the newly born child, and of the child into the man. Now, if we are to reason from this case of individual development to the other case of successive generations of creatures differing from each other in the same or any other ratio in which the perfect man differs from the ovum, the foetus, or the newly born child, which are all successive stages of one and the same individual life, we ought to find in the successive generations of the different creatures some bond of connection, some continuity of lives with lives, some perpetuation from one organism to another, that will constitute the "appropriate conditions" for a corresponding development from a single cell through the successive types of animal life into the human race. Without such connection, continuity, perpetuation from organism to organism, shown by some satisfactory proof, we have nothing but a theory, and a theory that is destitute of the grand conditions that will alone support the analogy between the two cases. If anywhere in the supposed chain of successive generations of different animals the continuity of animal and animal is broken, the hypothesis of special creations of new organisms must come in: for we must remember that we are reasoning about animal life, and if the continuity of lives with one another is interrupted, the series terminates, just as the series between the ovum, the foetus, the child, and the man terminates, at whatever stage it is interrupted by a cause that destroys the mysterious principle of life. It is therefore absolutely necessary to look for some proof which will show that in the supposed series of successive generations of animals out of antecedent types, by whatever gradations and in whatever space of time we may suppose the process of evolution to have been worked, there has been a continuity of life between the different types, a perpetuation of organism from organism, a connection of lives with lives.

We now come to another supposed analogy, on which great stress is laid by the evolution school, and especially by Mr. Spencer. Individuals of the same family are found to be marked by striking peculiarities of structure, ancestral traits, which appear and disappear and then appear again, in successive generations. This is obviously a case where the "appropriate conditions" are all comprehended in the connection of life with life. When we trace the pedigree of a single man or any other individual animal back to a remote pair of ancestors, we connect together in an unbroken chain the successive generations of parents and offspring. If the chain is anywhere broken, so that direct descent can not be traced throughout the series, we can not by direct evidence carry the peculiarities of family traits any further back than the ancestor or pair of ancestors with which we can find an unbroken connection of life with life. We do indeed often say in common parlance that an individual must have a trace of a certain blood in his veins, because of certain peculiarities of structure, complexion, or other tokens of descent, even when we can not find a perfect pedigree which would show where the infusion of the supposed blood came in. But although it might be allowable, in making out the descent of an individual man or any other animal, from a certain ancestor or pair of ancestors, to aid the pedigree by strong family or race resemblance, even when a link is wanting, it could only be for the purpose of establishing a pedigree, a connection of lives with lives, that such collateral evidence could be resorted to. If by direct proof of an unbroken descent a full pedigree is made out, or if, when some link is wanting, the collateral proof from strong family or race resemblances is sufficient to warrant the belief that the link once existed, we might accept it as a fact that the individual descended from the supposed ancestors in a direct line, or that some peculiarity of blood came into his constitution at some point in the descent of individuals from individuals.[74]

Can we apply this mode of reasoning to the evolution of distinct types of animals out of antecedent and different types? The very nature of the descent or derivation that is to be satisfactorily established requires a connection of lives with lives, just as such a connection is required in making out the pedigree of an individual animal. We must construct a pedigree for the different classes or types of animals through which, by direct or collateral evidence, we can connect the different organisms together, so as to warrant the belief that by the ordinary process of generation these animals of widely different organizations have been successfully developed out of each other, life from life, organisms from organisms. The hypothesis is, that from a single cell all the various races and types of animals have in process of time been gradually formed out of each other, through an ascending scale, until we reach the human race, whose race pedigree consists of a series of imperceptible formations, back to the single cell from which the whole series proceeded. This, we must remember, is not a case of the evolving production of different forms of inanimate matter, but it is the case of the evolving production of different forms of animal life out of other preceding and different forms, by the process of animal generation.

Of direct evidence of this evolution of species, it can not be said that we have any which will make it a parallel case with the direct evidence of the descent of an individual from parents and other ancestors. We have different animal organisms that are marked by distinctions which compel us to regard them as separate species, and there is no known instance in which we can directly trace a production of one of these distinct species out of another or others by finding a connection of lives with lives. Even in the vegetable kingdom, with all the crosses for which Nature has made such wonderful and various provision, we do not find such occurrences as the production of an oak out of the seed of an apple, or the production of an orange-tree out of an acorn. We do not gather grapes of thorns or figs of thistles. There are barriers set to miscegenation even in the vegetable world, and we have no direct evidence that at any period in the geological history of the earth these barriers have been crossed, and very little indirect evidence to warrant us in believing that they ever have been or ever will be. In the animal kingdom such barriers are extremely prominent and certain. We not only have no direct evidence that any one species of animal was at any period of the earth's history or in any length of time gradually evolved out of another distinct species, but we know that the union of the sexes and the production of new individuals can not take place out of certain limits; that, while Nature will permit of the crossing of different breeds of the same animal, and so will admit of very limited variations of structure, she will not admit of the sexual union of different species, so as to produce individuals having a union of the different organisms, or a resultant of a third organism of a different type from any that had preceded it. Is it, for example, from mere taste or moral feeling that such occurrences as the sexual union between man and beast have not been known to have produced a third and different animal? We know that it is because the Almighty has "fixed his canon" against such a union in the case of man and in the cases of all the other distinct animal organisms; and to find this canon we do not need to go to Scripture or revelation, although we may find it there also.

We are remitted, therefore, to indirect evidence, and in considering this evidence we have to note that we have nothing but an imaginary pedigree, or one hypothetically constructed, to which to apply it. In tracing the pedigree of an individual animal, we have a certain number of known connections of life with life; and where it becomes necessary to bridge over a break in the connection so as to carry the line back to an earlier ancestor, we may perhaps apply the collateral evidence of family or race resemblance to assist in making the connection with that particular ancestor a reasonably safe deduction. But in the case of the hypothetical pedigree which supposes the human race to have been evolved from a single cell through successive organisms rising higher and higher in the scale of being, we have no known connections of lives with lives to which to apply the collateral proofs. The collateral proofs are not auxiliary evidence; they are the sole evidence; and unless they are such as to exclude every other reasonable explanation of the phenomena which they exhibit excepting that of the supposed evolution, they can not be said to satisfy the rules of rational belief in the hypothesis to which we apply them.

What, then, is the indirect and collateral evidence? It consists, as we have already seen, of two principal classes of phenomena: first, resemblances of foetal development which are found on comparing the foetal growth of different species of animals; second, resemblances in the structure of different species of animals after birth and maturity. These various resemblances are supposed to constitute proof of descent from a common stock, which may be carried back in the series as far as the resemblance can be carried, at whatever point that may be. Thus, in comparing all the vertebrata, we find certain marked peculiarities of structure common to the whole class: the deduction is, that all the vertebrate animals came from a common stock. In comparing all the mammalia, we find certain marked peculiarities of structure common to the whole class: the deduction is that all the mammalia came from a common stock. Going still further back in the supposed series, we come to the amphibians, as the supposed common stock from which the vertebrate and mammalian land animals were derived; and, comparing the different classes of the amphibians, we find certain resemblances which point to the fish inhabitants of the water as their common stock; and then we trace the more highly organized fishes through the more lowly organized back to the aquatic worm, which may itself be supposed to have been developed out of a single cell.[75]

The resemblances of structure, wherever we make the comparison between different species, are referable to an ideal plan of animal construction, followed throughout a class of animals, and adjusted to their peculiar differences which distinguish one species from another, just as in the vegetable world there is an ideal plan of construction of trees followed throughout a class of plants, and adjusted to the peculiar differences which distinguish one kind of tree from another. As between man and the monkey, or between man and the horse, or the seal, or the bat, or the bird, there are certain resemblances in the structure of the skeleton, which indicate an identity of plan, although varied in its adjustments to the distinguishing structure of each separate species of animal. In a former chapter, I have shown why the adoption of an ideal plan of a general character is consistent with what I have called the "economy of Nature" in the special creation of different species. On a careful revision of the subject, I can see no reason to change the expression, or to modify the idea which it was intended to convey, and which I will here repeat. It is entirely consistent with the conception of an infinite and all-wise creating power, to suppose that in the formation of a large class of organisms, all the constructive power that was needed for the formation of a general plan was exercised throughout the class, and that there was super added the exercise of all the power of variation that was needful to produce distinct species. Repetition of the same general plan of construction is certainly no mark of inferiority of original power, if accompanied by adaptations to new and further conditions. It is a proof that in one direction all the necessary power was used, and no more, and that in producing the distinct organisms the necessary amount of further power was also used. If we follow the resemblances of structure that may be traced through all the animals of a varied class, we shall find that they may be referred, as a rational and consistent hypothesis, to this method of giving to each animal its characteristic formation. If this is a rational hypothesis, it is so because it is consistent with all the observable phenomena; and consequently, the opposite hypothesis that all these phenomena of resemblances and differences are due to the law of evolution does not exclude every other explanation of their existence.

To apply this now to one of the comparisons on which great stress is laid—the comparison between the brain of man and that of the ape. Two questions arise in this comparison: 1. Do the resemblances necessarily show that these two animals came from a common stock? 2. Do the resemblances necessarily show that man was descended from some ape through intermediate animals by gradual transformations? And, when I ask whether the comparison necessarily leads to these conclusions, I mean to ask whether the resemblances point so strongly to the conclusions that they must rationally be held to exclude every other hypothesis.

Prof. Huxley furnished to Mr. Darwin a very learned note, in which he stated the results of all that is now known concerning the resemblances and differences in the structure and the development of the brain in man and the apes. The differences may be laid aside in the present discussion, because it is not necessary, for my present purpose, to found anything upon them. But the resemblances, just as they are stated by the eminent anatomist, without regard to controverted details, are the important facts to be considered. The substance of the whole comparison is that the cerebral hemispheres in man and the higher apes are disposed after the very same pattern in him as in them; that every principal "gyrus" and "sulcus" of a chimpanzee's brain is clearly represented in that of a man, so that the terminology which applies to one answers for the other; that there is no dispute as to the resemblance in fundamental character between the ape's brain and man's; and that even the details of the arrangement of the "gyri" and "sulci" of the cerebral hemispheres present a wonderfully close similarity between the chimpanzee, orang, and man.[76] These are said to be the result of a comparison of the adult brain of man and the higher apes; and, although it is claimed by some anatomists that there are fundamental differences in the mode of their development which point to a difference of origin, this is denied by Huxley, who maintains that there is a fundamental agreement in the development of the brain in man and apes. His views of the facts for the purpose of the present inquiry may be accepted without controversy, not only because he is an authority whose statements of facts I am not disposed to dispute, but because it is not necessary to dispute them. What, then, do they show?

They show that there are animals known as apes and animals known as men, whose brains are found to be fundamentally constructed upon the same general plan, with strong resemblances throughout the different parts of the organ; and the first question is, Do these resemblances show that the two animals came from a common stock? Upon the theory that man has resulted from the gradual modifications of the same form as that from which the apes have sprung, the resemblances in the structure of their respective brains are claimed as having a tendency to show that there was an animal which preceded both of them, and which was their common ancestor, in the same sense in which an individual progenitor was the common ancestor of two other individuals, whether one of these two individuals was or was not descended from the other in a direct line. On the other hand, upon the hypothesis of the special creation of the ape as one animal, and the special creation of man as another animal, there was no common stock from which the two animals have been derived, and the resemblances of their brains point to the adoption of a general plan of construction for that organ, or its construction upon the same model, and the adaptation of that model to the other parts of the structure, and the purposes of the existence of each of the two animals. Without again repeating the argument which shows that the latter hypothesis is perfectly consistent with the professed conception of the infinite power, I will now inquire whether, on the former hypothesis, we have anything to which we can apply the evidence of resemblance as a collateral aid in reaching the conclusion that these two animals were derived from a common progenitor, or from some antecedent animal whose brain and other parts of the structure became modified into theirs by numerous intermediate gradations.

Between the higher apes, or between any of the apes and any known antecedent and different animal, no naturalist has discovered the intermediate link or links. Darwin supposes that there was some one extremely ancient progenitor from which proceeded the two main divisions of the SimiadÆ—namely, the Catarrhine and Platyrhine monkeys, with their sub-groups. This extremely ancient progenitor is nothing but a scientific hypothesis; or, to use a legal phrase, it had nothing but a constructive existence. It is necessary to believe in the principle of evolution, in order to work out the hypothesis of this creature from which the two great stems of the SimiadÆ are supposed to have proceeded. Here, then, we have the case of a pedigree or succession of animal races, the propositum of which has no known existence. Next we have two known divisions of the SimiadÆ, or monkeys; but, between them and their imaginary common progenitor, we have no known intermediate animals constituting the gradations of structure from the progenitor to the descendants. The whole chain has to be made out by tracing resemblances among the animals of a certain class that are known, then applying these resemblances to the supposed divergencies from the structure of a supposed progenitor, and then drawing the conclusion that there was such a progenitor. It may be submitted to the common sense of mankind, whether this is a state of facts which will warrant scientists or philosophers in using toward those who do not accept their theory quite so much of the de haut en bas style of remark as we find in the writings of Mr. Spencer.[77] If the researches of geologists had ever discovered any remains of an animal that would fulfill the requirements, and thus stand as the progenitor of the SimiadÆ. By the case would correspond to that of a known individual from whom we undertake to trace the descent of another individual through many intermediates; and in such a case strong family resemblances of various kinds might possibly afford some aid in making out the pedigree as a reliable conclusion. But there is no means of connecting the Old World and the New World apes with any but an unknown and imaginary, progenitor. Darwin himself frankly tells us that "the early progenitor of the whole Simian stock, including man," is an undiscovered animal, which may not have been identical with, or may not even have closely resembled, any existing ape or monkey.[78]

Passing from the supposed common progenitor to the resemblances between the brain of the higher apes and the brain of man, we come to the question whether these resemblances show that man was descended from any of the Simian stock through intermediate animals by gradual transformation. Here the case is in one respect different; for the animals that are to be compared are known, and their respective brains have been subjected to close anatomical scrutiny. This part of the process of evolution begins from one true species, the ape, and ends in another true species, the man. We are unable to trace the man and the ape to a common progenitor race; but we find the ape possessed of a brain which strongly resembles man's. I have searched diligently in the writings of naturalists for a sound reason which ought rationally to exclude the hypothesis that the brain of the ape was formed upon the same ideal plan as the brain of man, each animal being a distinct species and separately created. Anatomical comparison of the two brains shows that, whether they were separately planned upon the same general model, or the one was derived from the other by a process of gradual transformation through successive intermediate animals, the resemblances are consistent with either hypothesis. We are remitted, therefore, to an inquiry for the evidence which will establish the existence of a race or races of animals through whom there descended to man the peculiar structure of brain found in one of the classes of apes—namely, the Catarrhine or Old World monkeys. If such intermediate races could be found, their existence at any period anterior to the period of man's appearance on earth would have some tendency to show that man was descended from one of the families of apes, and this tendency would become stronger in proportion to the number of successive links in the family chain that could be made out. But not one of these links is known to have existed. There is an assumption that man, "from a genealogical point of view, belongs to the Catarrhine or Old World stock" of monkeys; and this assumption is claimed to be supported by the fact that the character of his brain is fundamentally the same as theirs.

A brain is an organ which, upon the hypothesis of an independent creation of distinct species of animals, would be expected to be found in very numerous species, although they might differ widely from each other. In all the vertebrate animals this organ is the one from which, by its connection with the spinal chord, the central portion of the nervous system, that system descends through the arches of the vertebrÆ, and thence radiates to the various other organs of the body. The brain is the central seat of sensation, to which are transmitted, along certain nerves, the impressions produced upon or arising in the other organs; and it is the source from which voluntary activity is transmitted along other nerves to organs and muscles that are subjected to a power of movement from within. The office which such an organ performs in a complex piece of animal mechanism is therefore the same in all the vertebrate animals in which it is found; and it would necessarily be found to be constructed upon the same uniform plan, and with just the degree of uniformity and adaptation which would fit it to perform its office in the particular species of animal to which it might be given. In point of fact, we find this office of the brain performed in all the vertebrate animals upon the same uniform plan, with the necessary adaptations to the various structures of the different animals. Resemblances, therefore, in the convolutions of different parts of this organ, as found in different vertebrate animals, however close they may be, prove nothing more than the adoption of a general plan for the production of objects common to the whole class of the vertebrate animals; and unless we can find other and independent proof that one species was descended from another by connection of lives with lives through successive generations, the hypothesis of special creations of the different species is not excluded by the facts.

Let us now further examine the supposed kinship of man with the monkey, as evidenced by the similarity of the structure of the brains of the two animals, in reference to the supposed process of evolution as the means of accounting for the origin of two species so essentially distinct. How has it happened that different species have become completed and final types, transmitting, after they have become completed, one and the same type, by the ordinary process of generation, and not admitting of the sexual union with any other distinct species? On the theory of the evolution of animal out of animal, we must suppose that at some time the secondary causes of natural and sexual selection have done their work. It ends in the production of a species which thereafter remains one and the same animal, and Nature has established a barrier to any sexual union with any other species. If we give the rein to our imaginations, and, taking the process of evolution as it is described to us, suppose that in the long course of countless ages the struggle for existence among very numerous individuals has led to gradual transformations of structure which the sexual selection has transmitted to offspring, and so a new animal has at length been formed through the successive "survivals of the fittest," we reach an animal of a new species, and that species, under no circumstances, produces any type but its own, so far as we have any means of knowledge. All the knowledge respecting the ape that has been accumulated shows only that this species of animal, since it became a completed type, has procreated its own type and no other. Whatever struggle for existence the individuals of this type have had to undergo, whatever modifications of structure or habits of life the survival of the fittest individuals of this type may have produced from the earliest imaginable period until the present time, the fact remains that this species of animal is a completed and final product. At the same time we have another completed and final type of animal known as man, which, so long as he has been known at all, is a distinct and peculiar species. Between the brain of this animal and the brain of the other we find certain strong resemblances. In each of them this organ is a structure performing the same office in the animal mechanism, with adaptations peculiar to the varying structure of each of them. In order to justify the conclusion that the one animal is a modified descendant from the other, so as to exclude the hypothesis that the resemblances of any one or of all of their respective organs was a result of the adoption of a general plan in special creations of distinct species, we ought to find some instance or instances in which the completed animal called the ape has been developed into an animal approaching more nearly to man than the man, as he is first known to us, approached to the first ape that is known to us. Without such intermediate connections, the analogy of the descent of individuals from other individuals of the same species will not hold. There is nothing left but resemblances of structure in one or more organs, which are just as consistent with the hypothesis of special creations as with that of evolution. Strong resemblances of structure and in the offices of different organs may be found between man and the horse, but upon no theory of evolution has it been suggested that man is descended from the horse, or from any other animal to which he bears more or less resemblance, excepting the monkey; and it is quite possible that naturalists have been led unconsciously to make this exception by external resemblances of the monkey and the man, by the imitative power of the inferior animal when it comes in contact with man, and by some of its habits when found in its wild and native haunts.