CHAPTER VI
THE DIRECTIVE THEORY OF EVOLUTION
“Who is there that cannot distinguish between the actual cause of a thing and that without which the cause could never be a cause?”—Plato, Phædo.
The problem set at the close of our first chapter was to find a fit explanation of the guiding power apparent in natural phenomena. We have not been able to interpret this guiding power either in terms of conscious, intelligent contrivance or in terms of blind, mechanical law. The investigations which followed have led us up to another explanation. We have seen that the vivifying, transforming, progressive power in nature may be conceived as a power of Response. Every particle of matter, organic and inorganic, has this power. Every particle of matter can react and respond to some stimulus. The more it can respond to, the higher it is in the scale of being. And we have found, as I think, one constant and universal stimulus to which both the fixity of nature’s laws and the plasticity of her mysterious substance may be conceived as a response. This stimulus is the call of Life. Stimulus and response taken together constitute the directive force in obedience to which the world unfolds itself in the evolutionary process. We have been led to interpret nature as the concrete expression of the will to live, a will which for the first time comes into rational consciousness in man. Having brought this conception, I hope, into clear light, it is the aim of the present chapter to illustrate and enforce it in more detail, and thus to gain a secure foundation for the application of the conception to the more strictly human problems with which we have ultimately to deal.
It must be confessed that the existence in nature of any directive power transcending and utilizing the mechanical forces and relations of matter, call it ‘vital force,’ the ‘hand of Providence,’ the ‘X’ of evolution, or what one will, has never readily been admitted by scientific naturalists. They feel that, if once admitted, it offers a prompt and facile explanation of every difficulty, and is available as the cheap resource of all those who study nature with a view to the grinding of their moral or religious axes, rather than to the discovery of truth. Those who feel obliged to believe in the existence of some such power are therefore bound to be more than ordinarily on their guard against all loose thinking. They must not be content with vague generalities, but must be prepared to indicate as exactly as possible the distinction existing between the mechanical and the non-mechanical or transcendental agencies in nature. It does not follow that one’s account of the matter will prove to be exactly true in every detail. One must always speak in such matters with that wise reservation of Socrates, “If this be not the truth, something of the kind is.” But it is not allowable to fall back on that “something of the kind” until an attempt has been made definitely to establish the “kind,” by searching into the inmost heart of the fact.
The fact here is the responsive power of living protoplasm. It will be well to examine it first in its operation in an individual organism before we consider it in relation to the species.
Reaction or response of a chemical and mechanical type takes place alike in dead matter and in living organisms, but certain stimuli will induce action in an organism which they could not possibly induce in a mineral. For in every cell, as Reinke well says, there are a chemist and an architect who guide its energies, and who have something quite different from chemistry and physics in view. Consider the following case. Every tuber of a potato plant is covered with a light skin composed of a corky substance intended to protect the internal structure from injury. This skin is produced by the action of the surface cells of the tuber. Chemically and physically these cells are just the same as the cells in the interior of the tuber. But the interior cells do not produce this corky substance, because it would be injurious to the plant if they did. The cells below the surface of the tuber, though they are by no means secluded from the chemical influences of the earth around them, behave quite differently from those actually in contact with the earth.
Now let us take our tuber, slice it in half, and replace it in the earth again. If we look at it again in a few days we shall find that the interior cells, now exposed by the cutting, have done what they could not or did not do before—they have produced a layer of skin to cover the exposed surface of the tuber just as if they had been surface cells from the outset.
This kind of response seems to take us quite out of the region of chemical and physical action as understood in the case of inorganic matter. It is a response directed to maintaining as far as possible the life and form of the organism, a thing which mere chemical action in mineral substances never does.
It may perhaps, however, be argued that the actual contact with the earth has a possible chemical stimulus which is not communicable to cells even a hair’s-breadth below the surface, and that the cells laid bare by slicing react as they do simply because they are exposed to this stimulus. Let us take, then, another common and typical case of response to altered conditions in plant life.
The taproot of a tree, as we have seen,[86] grows straight downwards towards the centre of the earth in obedience to the stimulus given by the pull of gravitation. The same stimulus impels the stem to shoot upwards, and the other roots and the branches to grow more or less laterally. New growth always takes place at the extreme tip of the shoot or root. Lay bare the taproot, cut away this growing tip, and that root can grow no more; no fresh tip charged with vegetative vitality can form itself over the scar. But mark what happens! The nearest lateral root, instead of pursuing its normal course, straightway begins to bend downwards and takes the place of the mutilated taproot. Similarly if the leading shoot of the stem is nipped off, the nearest lateral branch will turn upwards. In this case the lateral root or shoot has not been subjected to any new influences whatever, or at least to none of a chemical or physical nature. Yet it responds, not to anything affecting itself, but to the needs of the organism as a whole.[87]
None of the forces which living organisms have in common with minerals will account for this kind of response.
How are we to represent to our minds the nature of the forces which apply to the innumerable cases of which the above is a type? Reinke, who deals exhaustively with this question, conceives the vitality of living things, manifested in growth, development, and reproduction, as lodged in what he calls “Dominants.”[88] These dominants exist in all parts of the organism, and govern those processes which ordinary physical laws do not explain, i.e. the phenomena which are specifically vital. They are not themselves chemical or physical energies, but they guide these energies toward the fulfilment of the objects of life.
“Dominants,” he writes,[89] “are those secondary[90] forces in the organism whose existence we recognize in their operations, but which we cannot further analyse. Thus I understand under this form that principle of control which takes effect in every organism and which sways whatever energies are available just as men use tools and machines. Since this control is manifold in its manifestations, one is obliged, when seeking for a technical designation for it, to express it in the plural. The dominants are therefore an abstraction; a symbol for phenomena, just like the conceptions, Force, Matter, the Atom, etc.; the term has been devised in order to provide a short explanatory description of certain essential processes.
“I therefore repel the objection, if anyone should make it, that the dominants are a fiction, a troop of ghosts with which I have peopled the cells and organs of animals and plants. They are, in some sense, merely a paraphrase of the description of certain phenomena, a personification of forces not to be ranged under the conception of energy—the directive impulses in the animal and vegetable world.”
To continue Reinke’s explanation: Two different classes of dominants are to be recognized. These are the operative and the formative. The former control principally the chemical activities of the organism, as when a plant turns inorganic substances into sugar, albumen, etc.; the latter are the invisible architects in the organism who control its form and structure. Both are heritable, and are capable of modification within certain limits. Closely bound up with matter and energy, they are neither matter nor energy. They can be indefinitely multiplied and (to all appearance) totally destroyed. Their multiplication does not abstract energy from other known sources, nor does their destruction restore it; they do not therefore come (visibly) under the law of the conservation of energy. They operate entirely within the framework of natural laws, and can only utilize what energies are available for them at the given time and place. Every cell has its dominants; and as an organism is a synthesis, not a mere aggregate, of cells, so its individual dominant is a synthesis of the dominants of its parts. The evolution of species, like the development of an embryo, is under the control of dominants. The conditions under which they work for this end are material and physical; these conditions can, to a great extent, be ascertained and defined, but the driving force lies beyond scientific analysis.
Such is the conception of Reinke; and taken as he presents it, that is to say, merely as a kind of working hypothesis, as a means of making intelligible a vast and various mass of phenomena, it seems admirably suited to its purpose. It remains to add, though Reinke himself does not say so, that this conception of the dominants appears to harmonize remarkably with what has been put forward in regard to cell-structure and reproduction. The chromosomes are probably the material vehicles of the dominants; in fact, Weismann’s determinants seem to be the same thing under another name, though Weismann conceives them rather from the point of view of the scientist, and Reinke from that of the metaphysician.
We have now arrived at an intellectual conception under which to range the phenomena (not the ultimate nature) of vital response. Let us apply it to the question of evolution. The following passage from Henslow’s Origin of Plant Structures[91] may serve to introduce this part of our discussion:—
“The question ... resolves itself into this: which probability or hypothesis do the facts of the case seem to favour most, viz. that indefinite variations arise from some assumed internal causes, of which variations only those in harmony with the environment survive, and are said, therefore, metaphorically, to be selected by it; or is it that the external forces of the environment excite the variability which is inherent in plants, and call into action the responsive power of the protoplasm in the various species of plants, which thus all tend to put on the same, or similar, or at least adaptive and definite variations of one sort or another, so that there are no indiscriminate or wasted variations[92] at all? I know an abundance of facts which support the latter contention, but none whatever in illustration of the former hypothesis.”
Here is the action of the dominants in evolution placed in the clearest light. To prove the truth of Professor Henslow’s contention it is necessary not only to study organisms in situations where they have been established for many generations or centuries, but to see how they behave on transportation to a new kind of environment. The cases which can be adduced are numerous and convincing. Thus Mr. D. Dewar reported to Mr. Henslow that on introducing at Kew a cress, Arabis anachortica, found in cave-like situations in the Alps, and having very thin, papery leaves, it turned, when raised from seed, into a different species, Arabis alpina. The change took only three generations to accomplish.[93]
Bulbous roots have it among their functions to store up moisture for the plant they belong to. Haeckel has shown that the grass Poa bulbosa, on being cultivated in moist soil, almost lost its bulbous character. Contrariwise we find that many plants not bulbous elsewhere are observed to be so when growing on the dry Karoo in South Africa.[94]
Spines on a plant are usual accompaniments of dryness in soil or atmosphere. Ononis spinosa has an excessively spiny variety, termed horrida, which is found on maritime sands. Grown in very rich moist situations, it gradually loses its spines and they ultimately disappear entirely.[95]
In the animal world experimental cultivation is not at all so easy, but the facts observed all go to support the view that the response to environment is direct and definite. The small shrimp-like crustacean, Artemia salina is a case frequently quoted. It lives in salt pools by the Black Sea, and it has been found that by breeding it in water of which the salinity is gradually decreased, the creature in a few generations assumes a type commonly assigned not merely to a different species but to a different genus—Branchipus stagnalis.[96]
Perhaps the most remarkable instance of a transformation produced by the influence of environment is that of the Mexican water-newt, Axolotl. When gradually accustomed to live on dry land, this creature usually throws off its gills, develops lungs, alters the shape of its tail, and takes on all the characteristics of a terrestrial instead of an aquatic reptile. This transformation does not take generations to accomplish—it happens in one individual in the course of a few weeks or months. When found in the terrestrial form, the Axolotl is called Amblystoma tigrinum, and is classed among the salamanders. Its progeny are then Amblystomas, and they do not naturally revert to the Axolotl type, although under certain circumstances the steps of this amazing transformation can be retraced. The Axolotl is not a larva in the ordinary sense of the word, for it is not an imperfect creature; it is sexually mature, and in most cases, in nature, probably never develops into an Amblystoma, nor do the progeny of the Amblystomas begin as Axolotls. What we have here is probably, as Weismann plausibly suggests, a case of a species which has almost reached the stage of evolution from an aquatic into a terrestrial form, so that a sufficient impulse from its environment suffices to send it over the border. Internal forces have evidently prepared the way for the change, and the process does not in the least resemble the mechanical selection of suitable characters from a crowd of fortuitous variations.[97]
The case of the Porto Santo rabbit may also be quoted in this connexion. In the year 1419 the young born of a tame Spanish rabbit were put ashore on the island of Porto Santo near Madeira. No rabbits then existed on the island. They have since increased enormously, and have quite changed their appearance. They have acquired a peculiar colour, are very small, rat-like in shape, have nocturnal habits, and are noted for their extreme wildness. They no longer pair with the European rabbit. The case was observed by Haeckel, who styled the new species Lepus Huxleyi.[98]
Cases like the foregoing show the organism affected during its process of transformation by large elemental influences, and the response to these influences is so familiar that often it does not surprise us. We veil the real mystery of the process by talking of the chemical and other physical properties of protoplasm which render this response possible. But when we come to the protective mimicry of stinging insects by stingless ones, of leaves by butterflies, and so forth, these physical explanations manifestly fail us. The explanation which assumes the building up of these extraordinary resemblances bit by bit, through natural selection working upon a multitude of fortuitous variations, fails us as completely. It would be difficult to accept it if only a single species of insect showed these mimetic markings. The unlikelihood of their production by mere chance in the case not of one but of hundreds of species of butterflies, flies, and caterpillars is stupendous, and defies all calculation. It must, we repeat, always be borne in mind that, if chance variations are all we can postulate, these variations must at first be confined to one or few individuals, and that the influence of intercrossing would always be at work to obliterate individual peculiarities before they could develop to the point of affording any protection worth mentioning. We are bound, therefore, so far as I can see, to conclude, first, that these mimetic markings originate not in individuals but in the species as a whole, and are an expression of the communal life of the species; secondly, that they are a real and direct response to the external conditions of danger from attacks of birds, etc., and of protection afforded by deceiving these foes through mimicry of something which they do not care to attack. They can only originate in the dominants of the reproductive cells, and there, where undoubtedly forces and affinities of which we have no conception are ever at work, the initial changes take place. These changes, no doubt, take place by forming new combinations or modifications of existing dominants. The directive force must have something to work on. It does not follow that because some things are possible to it therefore all things are. It is not to be expected, for instance, that human beings, although it would be a great advantage to them to fly, could ever develop wings, like the conventional angels of mediæval art, for that would violate the essential character of the archetypal form. It is true, however, that life is ultimately responsible for the material with which it works as well as the directive agency that breathes through it. This point is of importance and must be made perfectly clear. The view of cosmic action here put forward does not contemplate ‘interventions’ in the order of nature from a source outside it. There never was a moment when, if law prevailed, one result would take place, while another result actually does occur in obedience to some mysterious life-force. No; it is the life-impulse which makes the law, obeys it and utilizes it. One can never say, “Such and such would have happened if the life-force had not been in action, but, as it was, the event was so-and-so”; for if it were not in action nothing would ever happen at all—the Universe would be the Eternal Nothing. One might as well speculate as to what would happen in a game of whist if nobody held a trump. The voluntary limitations under which nature works resemble, in the conception here put forward, the playing of a game, say a game of ‘Patience,’ where there is only one player, who plays the game with himself. There are laws to be obeyed, combinations which are necessary, but a guiding force can take advantage of the conditions as they arise and lead them to a certain end. If there were no laws and conditions there would be no game. If, on the other hand, matter were absolutely plastic life could not realize itself; nature’s game would be finished ere it was begun. A concrete illustration may, while we are on this topic, serve to suggest the kind of limitations under which nature seems to work.[99] During the last century or so the African elephant has been ruthlessly hunted down for its ivory, and since rifles and expanding bullets came into play the process of extermination has been greatly hastened. Elephants are now, I believe, protected by law over a great part of South Africa, but if it were not for this the species would at present be in considerable danger of extinction. The case is very like that of the Kallima butterfly and similar mimetic forms before they acquired their protective markings. Now, how might we expect nature to attempt the protection of the elephant? Doubtless by increased fleetness, cunning, watchfulness, capacity of one kind or another for concealing itself from hostile observation. But could we look for any such development as, for example, a deterioration in the quality of the ivory? Suppose, for example, the interior structure of the tusk were to become spongy and cellular instead of being dense. The tusk, if coated with hard enamel, might be almost if not quite as useful to the elephant, but it would cease to be of any use for most of the purposes to which it is now applied by man. The protection would be most effective; yet we know that nothing of this kind can possibly take place, though intrinsically the process would be far less remarkable than the painting of the butterfly’s wing. It cannot take place because it would either imply a supernatural knowledge on the part of the evolution-dominants of the elephant tribe of the reasons why it is hunted, or a conscious supervising and co-ordinating power above nature, a manlike Deity, omnipotent and omniscient, such as Paley assumed; to both of which explanations the actual processes of nature stand uncompromisingly opposed.
It is much easier to say what the life-impulse is not than what it is. I cannot, for my own part, conceive it as personal or conscious, in the sense in which I feel myself a conscious person. If we ask, Has it or has it not the quality of intelligence? we shall find both the affirmative and the negative answers equally hard to square with the facts. Our own intelligences working in a mysterious relation to a bodily organism are perhaps fundamentally incapable of forming a clear idea of the nature of the cosmic intelligence which is revealed to us in the outside world, “like the dim view of a country seen in the twilight, with forms half extricated from the darkness, with broken lines, and isolated masses.”[100]
But those who find it difficult to believe that anything having the nature of intelligence is at work in the physical world might reflect on the striking analogy which that world offers to a certain sphere where it is quite certain that the human spirit, including its intelligence as well as its appetites and instincts, is the governing power. Social institutions are a product of the human spirit. Yet the development of these institutions is extraordinarily like that of the functions and structures of an animal or vegetable organism. The value of Mr. Herbert Spencer’s philosophic system may be disputed on many points, but his elaborate analysis of the phenomena of social life and his exposition of the minute analogies they exhibit to the processes of evolution in nature must always remain a landmark indicating the conquest of a great territory of human thought.[101] Here, as in nature, we find a principle of movement and progress conflicting with a principle of inertia. We find all grades of development existing at the same time. We see the gradual progression, by means of all kinds of by-ways, to a goal which one might have expected intelligence to attain simply and directly. We see parallels in human societies to arteries, nerves, to co-ordinating and ruling brain-centres, to the specialization of different members or organs for different tasks; and we see all these things growing up slowly, from point to point, in obedience to immediate and pressing requirements. We find, both in nature and in society, survivals of past structures, whose use is gone, carried forward into new stages of development. A particularly interesting analogy is that of structures which develop to meet one kind of requirement, and, on the cessation of that, persist into a further stage and are then modified to meet quite other requirements. Thus the swim-bladder of the fish became, it is supposed, the lung of the terrestrial animal. We may compare this with the development of municipal institutions. Originally intended to enable bodies of craftsmen and merchants to make head against the aggressions of a feudal aristocracy they have survived the fall of feudalism, and have become more important than ever as independent agencies for carrying on the functions of social administration and education.
Thus, operations in the physical world which certainly do not look as if they were the work of intelligence, as we understand it, are seen to be closely paralleled by transactions in the history of man’s social life. The development of life, in fact, is carried forward when the plane of human consciousness is reached on just the same lines as those which prevailed on the vegetable and the animal plane: there is no breach of continuity in the broad outlines of evolutionary progress. It is difficult to over-estimate the significance of this fact.
Perhaps nothing that man has evolved is so purely a work of mind as Language. Here, the analogy with the phenomena of physical evolution is very close and very illuminating. As in nature, the ultimate origins are obscure—we can only form hypotheses as to how language came to arise from the cries of animals, as we can only form hypotheses how life arose from the play of molecular forces. But when both are once established on the earth we see in them the same general features—unity, in a few leading types, branching out into infinite modifications in subordinate groups. Greek, Erse, German, Russian, Sanskrit are all Aryan tongues and have all a common ancestry. They differ widely among each other, but all alike are marked off from the Semitic or the Mongolian families. So a man, a snake, a bear, a fish are all vertebrates, and belong to a type essentially distinct from that of a lobster or a snail. As in nature, we find all stages of development existing at the same time—some lines of development show a rapid advance, some a very slow one. Some types have, in both cases, perished completely—there are fossil languages as there are fossil species. A new invention, an advance per saltum, without the utilization of existing constituents, is almost as rare in the evolution of language as in that of species. Just as the lung is developed from the swim-bladder, so the human mind, in the development of language, takes hold of whatever existing form will suit its purpose and transforms it to another end, as when it takes a word for ‘breath’ and makes it ‘spirit.’ There are laws governing the development of root-forms, linguistic or physical, in various different orders or species. The same osseous framework yields us in one class of animal a hand, in another a hoof, in another a paw, in another (as in bats) a wing. So in language the same root yields us the words, in different languages, for shining, showing, speaking, proving, a face, a story, whiteness. Another gives us, young, a stepmother, a certain musical string, a messenger.[102] Contrariwise we see both in nature and in language forms which have grown from entirely different roots into a close external and functional similarity. What unlearned observer would suspect that a whale was not a fish, and that it descends from a furry land animal with four legs, or that the Latin Deus and the Greek Theos with their perfect identity of meaning and their almost perfect identity of sound have probably a widely divergent etymological pedigree?[103]
On the other hand, the etymological identity of such words as évêque and bishop is as obscure on the surface as would probably be the relationship of a greyhound with a bull-dog to an anatomist who saw them only in fossil form.
Again we note that languages, like species, when they send out a migratory colony, are capable of gradual transformation to meet new conditions, and of marked divergence from the parent stock. Thus English, as spoken and written in the United States, in spite of the retaining influence of a common literary tradition, is steadily diverging from the English of Great Britain.[104] So with the French of Canada, the Spanish of South America, and the Dutch of the Cape. We note also in both cases that curious phenomenon, the survival of the useless relics of earlier structure, e.g. in the silent letters which reveal the historic origin of innumerable English words, which are paralleled in nature by the vermiform appendix of man, or the splint bones in a horse, or the rudimentary legs of the whale or the python.
But analogies of detail like these, interesting as they are, are not the main thing. The main thing is the organic likeness prevailing between the work of nature and this work of man—the likeness of growing and developing structures, with their response to immediate needs, their development by specialization of function, their lack of a strict logical scheme, their anomalies and capricious variations, and their control of these variations within certain archetypal forms. The substance of language is sound, as the substance of life is protoplasm. Phonetic laws govern the one as mechanical and chemical laws do the other. But phonetic laws and the capability of producing sound could never have made a language. The evolution of language is urged forward by the constant pressure and expansion of human thought; and on human thought, in its turn, it reacts, giving the stimulus and the starting ground for fresh expansion. We have the heart of the analogy before us now. As thought acts on language so the pressure and expansion of the life-impulse acts on the forms of matter. Let us see whither the comparison leads us. Language is a product of the human mind, but not of a mind. When a human mind consciously applies itself to the fashioning of a language it produces Esperanto. If we were living in an Esperanto universe, such as Paley makes out this to be, we might draw Paley’s easy conclusions as to its Maker; but the reality is very unlike that. On the other hand, if mind has produced the natural languages which we see, with all their anomalies, imperfections, and slow organic growth, then the corresponding phenomena in nature, as the evolution doctrine has brought them out, are evidently no bar to the belief that mind has had a part in this work also. I should go farther and say that the facts compel a belief in the existence in nature of something that can only be described in terms of mind. In other words, the universe is, at bottom, rational.
It is true that the cosmic Reason acts not as a single personal being, but more or less independently at a multitude of points. But it must not be forgotten that it is observed, up to a certain point, to act through groups as well as through units. Even the life and structure of a single cell show us distinct parts acting in harmonious subordination to the interests of the whole. An organism composed of many of these cells exhibits a series of syntheses or groupings rising in comprehensiveness and complexity till the individual is complete and the wheel of development has come full circle, beginning with a single unit and ending with a complex unit. But the synthetic movement of cosmic control does not end there,[105] for aggregates of individuals can be collectively animated by it. The numerous cases of co-operation among animals of the same species are an instance of this. All animals which live in communities exhibit this co-operation habitually, and many others do so occasionally. When Professor Eimer, as we have seen, reflected on the phenomena of reproduction and heredity in ants and bees, he was driven, like Oken, to account for them by regarding these creatures as “discontinuous organs” of one being, having the same power of affecting each other as have the distinct, though connected, parts of any single animal or plant.[106] As an illustrative analogy, helping us to understand the invisible bond of the communal life of a species, this conception is of service, but I hardly think that we are in a position at present to affirm it in any exact and literal sense. Can we, however, trace the analogy, as Oken did, beyond species, and show anything of the nature of an adaptation of one order of beings to the use of another? To do so convincingly, it is evident that the adaptation must be of no use to the creature possessing it; for, if it were, we might expect to see it evolved, whether it were incidentally of use to a neighbour species or not. Honey, for instance, though apparently of no direct use to flowers, is secreted by them because it attracts insects, and insects fertilize the flowers. If flowers secreted honey solely for insects’ use, deriving no benefit from their visits, we should have a case of a synthesis of communal life wider than that of the species. Are there such cases, or does every species fight exclusively for its own hand?
“If,” wrote Darwin, “it could be proved that any part of the structure of any one species had been formed for the exclusive good of another species, it would annihilate my theory, for such could not have been produced through natural selection.”[107]
Certainly it could not, but neither could other adaptations. Natural selection, as Darwin knew well enough, does not “produce” anything—all it can do is to depress the less favourable variations presented to it in favour of the more favourable ones. As Darwin never professed to have sounded the depths of the problem of variation, it is not clear why variations favourable to another species than the one in which they occur should be presumed to be impossible. It is true that they would not illustrate or come under the operation of natural selection, but neither would they contradict it—they would simply be outside it. Individuals unquestionably exhibit modifications intended not for their own personal benefit, but for that of the species—for instance, the maternal instincts. The modification of a part in the interest of the whole to which it belongs may, perhaps, turn out to have the same essential significance whether the part is an organ or instinct belonging to the synthesis called an individual, or an individual belonging to the synthesis called a species, or a species belonging to some fauna or flora of the globe. In any case, the question where synthesis is arrested, and where the fight for one’s own hand begins, is one of great interest and must be here briefly discussed. Cases such as those of which Darwin rejected the possibility certainly appear to be rare, if they exist at all. The naturalists of the older school, of course, saw them everywhere—the rattlesnake’s rattle was to warn its victims, the colouring of flowers was to give pleasure to man, and so forth. Most of these cases have been exploded by modern research. The modern naturalists, however, may not be right in refusing to see them anywhere. The question demands much special study and observation. Reverting to the case of flowers and their secretion of honey, one is struck by the fact that in the Viola family there exist flowers more or less conspicuous, and endowed with scent and with honey-filled nectaries, which usually do not play any part at all in fertilization. The process of fertilization in Viola is carried on by small flowers hidden under the leaves which never open, and which fertilize themselves. Again, at the base of the laurel leaf, on each side of the midrib, there are two small glands filled with honey, and bees may be observed biting into these in the early part of the year before flower-honey is plentiful. Nägeli has an ingenious argument to show the existence, not exactly of disinterested aid among species, but of something which would make such aid look more possible than it does, of a mutual responsiveness, namely, between the form of the honey-receptacles of certain flowers and the probosces of the insects which frequent them. Taking a short honey-tube as the normal and original condition among plants, and a short proboscis among insects, he argues that the honey-tube could not have lengthened without depriving the species in which it did so of the chances of insect-fertilization unless the insect-proboscis in certain species lengthened simultaneously.[108] Cases also have been noticed of sea-anemones, which attach themselves to the shells of hermit crabs and by their poisonous tentacles repel attacks on the crab.[109] The crab is no doubt useful to its guest by providing it with the means of locomotion. Still, the case of mutual help between two such different orders of beings is remarkable. A very peculiar case is that of the waterfern, Azolla, which has certain roomy cavities on the underside of its leaves. These are always found to be occupied by a small unicellular organism of the Alga order (Anabæna). It is of no apparent use to the Azolla, which provides it a home. The arrangement must have been of immensely long standing, for it occurs in all the four species of Azolla, one of which is found in America, two distributed over Australia, Asia, and Africa, and one only in the Nile. It must, therefore, have arisen before the original species split into four.[110]
It would be rash to conclude from these and some similar curiosities that we are really in the presence of the phenomenon of disinterested aid given by one species to another. The question needs more investigation. But an important general consideration arises in this connexion. It is clear that there could be no advance in evolution if nature consisted solely of a multitude of independent units of life, fiercely competing against or warring with each other. It is equally clear that no advance could take place if every organism found an environment so perfectly adapted to it as to call for the very minimum of effort and strain in the maintenance of life. Between the chaos of the first supposition and the lubberland of the second there must be a condition of nature in which synthetic organization is carried just to the point at which life will have the maximum power to perfect and to realize itself. Looking at the conditions of nature as we know them, and at the majestic expression of material and spiritual life which those conditions have permitted, we may well be content to believe that both the synthetic process, as far as it goes, and its apparent suspension at a certain point in the ascending scale, are the outcome of one and the same motive and have one and the same significance—they both alike mean and make for the conservation, the development, the enrichment of life.
Against this view there is an argument which has hitherto only been glanced at, but which must now be discussed in more detail. It is represented in a recent work by Prof. Conrad Günther, one of the latest champions of the theory of chance variations and natural selection as the sole explanation of evolution, who has assembled a number of instances to show that the “purposive force” which biologists are now coming to believe in “often fails in living beings.” Such are, for example, the fact that an Amœba seeking nourishment will take in a particle of stone or anything that comes in its way;[111] that the mutual relations of flowers and insects are often unsuitable; that a bee will sting a human being just as it will another insect, although the sting, only meant for the latter kind of use, cannot be withdrawn from the human skin; that embryos often go astray during development; that a cricket which tries to escape in the open by burying itself in the earth will act similarly if you set it on a glass plate; and so forth. Nature, of course, teems with such cases—one might add the singular degeneration of the slave-making ants already described in some detail.[112] “If,” he concludes, “the purposive reaction in the vital force of animals were independent of the external world, they would be armed against all contingencies, and that is not the case.”[113]
Thus, too, Prof. Eimer, who in dealing with cases where the alleged X factor in Nature has gone wrong, writes:—
“The zoologist can hardly accept the existence of such a dominant inner factor ever pushing toward advance, when he recalls the host of regressive structures which he has to see.”[114]
Now when the cause of physico-chemical versus vital agencies comes to be tried, not in the laboratory but in the study, not by science but by philosophy, the first question that will be asked is, What, then, is your distinction between ‘vital’ and ‘physico-chemical’ energies? How are we to recognize when we are in presence of the one or of the other? The usual answer to this searching question is that in vital agency we find a directive, a purposeful, a psychic element, whereas physico-chemical energies seem to be nothing but the play of a blind, indifferent mechanism. But, it will be rejoined, how can any one affirm that physico-chemical energies are not also vital, directive, psychic? Is there not, in fact, something psychic in the very conception of energy? To these questions there seems to me no conceivable reply. When a ‘vital’ energy has been reduced to a ‘physico-chemical,’ we have evidently explained nothing—we have only exchanged one mystery for another.
Yet if there is no difference in essential nature between one kind of energy and another, there does appear a marked difference when we come to consider them in relation to particular results of their operation. Let us take an example. We explain that classic instance of gravitation, the fall of an apple, by reference to the law formulated by Newton which extends to every particle of matter in the visible universe. But we also find that the fall of the apple is, for apples, a necessity of life; if the seed did not fall to the ground when ripe there would be no more apple trees. Yet gravitation acts quite indifferently to the life of the apple. Whether the branches overhang a river, or a street, or a plot of fertile ground, the apple will fall straight towards the centre of the earth. The fulfilment, therefore, of the vital needs of the apple is plainly a by-product of the force of gravitation. In this relation, gravity has no directive or psychic element. Yet in larger relations, we have to take note of the fact that if there were no such thing as gravity, there would be no apples and no earth. Thus the law of gravitation is a condition of life as we now know it. The fact that it acts mechanically, without selection or purpose, in relation to particular occurrences is quite consistent with the view that it, or the conditions of the ether from which it possibly arises, may be directive and psychic in relation to life as a whole, or rather to what we recognize as the manifestation of life in the material universe.
We have now got hold of a valid distinction between mechanical and directive agencies. We can distinguish them not by their nature but in relation to the particular phenomenon we are considering. We call them mechanical where that phenomenon is a by-product of the agency, and directive where, if the agency were conscious, we should say that this was its main intent. I can see no more fundamental distinction. It follows from this that the same action can be at once both mechanical (physico-chemical) and directive. The old distinction between vital and mechanical energy disappears. The question resolves itself simply into that of the number of distinct agencies which are deemed necessary to account for the universe.
Now the true way of dealing with this problem of the unity or multiplicity of agencies in nature is, I would suggest, to assume the existence of a single power which is of course psychic and directive but which can only be communicated to matter by degrees and under certain conditions still very obscure. These conditions it itself both creates and uses. Its development in Time and that of matter go on, as it were, on parallel paths, eternally apart (to our limited view) yet eternally inseparable. The key to the course of its development in nature lies in the word Synthesis.[115] Here we seem to have the explanation of the apparent difference between the so-called ‘vital’ and the physico-chemical forces. When matter has been so grouped as to form not a mere aggregate of particles but a synthesis, then that synthesis is enabled to make use of energy in a manner not open to its parts. Synthesis is a condition of the discovery of liberation of unsuspected forces. Thus a synthesis of molecules produces the stage for Life, a synthesis of living particles produces the Cell, a synthesis of cells produces an organism, a synthesis of organisms is a species—for the evidence (most notably that derived from the consideration of bee and ant communities) seems to show that material discontinuity in the members does not preclude the existence of a true synthetic union.[116] The characteristic power gained by a species is that of evolutionary development working in the obscure region of germinal combination and variation. Of course, I am aware that all this is merely a way of representing facts so as to make them intelligible to and manageable by the mind. If any one should object that we do not know what kind of grouping a synthesis is, except precisely through that very organic activity which I have described as its product or accompaniment, I entirely agree. All these terms are intellectual forms—like atoms, molecules, and other concepts of physics. They do not reveal anything; they merely help us to comprehend. In the region of the controversy of Vitalism versus Mechanism, the conceptions which I have been trying to explain enable us, without introducing a multiplicity of different energies, to understand how an organism synthetized by life may exhibit directive action which looks entirely different from any action possible in dead matter. Yet it works under laws of its own, and no doubt the particles of such an organism, if they were conscious, would be unaware that any but physico-chemical processes were in operation; in fact, I should have no hesitation in agreeing with the statement with which the great physiologist, Verworn, concludes an exhaustive analysis of this obscure subject: “The general fact must be regarded as established, that all the work of the organism is based finally upon chemical energy.”[117] But what directs the chemical energy? Something which is not itself a chemical energy and which is associated with the organic synthesis which that energy serves to maintain. Verworn’s statement, it must be borne in mind, is as true of the composition of the Iliad as it is of the digestive process of an animalcule.
The explanations above suggested are purely tentative; but so, it must be remembered, are the theories which they combat. No one pretends that the mechanical explanation of the universe, including the phenomena of organic life, is at present made out so as to cover the known facts, or even that expert opinion is at all unanimous in the belief that it can ever do so.
I know no single work in which the present position of the controversy is so well set forth as in Professor V. L. Kellogg’s Darwinism To-day.[118] A great array of scientific authorities will there be found mustered, and the verdict of Professor Kellogg (reluctantly given, for he clings to the mechanical explanation of the universe) is that evolution is not explained by any mechanical force at present known to science. “With Osborn,” he concludes, “let us join the believers in the unknown factors in evolution.”[119] He does not, however, contemplate their remaining unknown—we have to say Ignoramus, not Ignorabimus; and by ‘known’ he means apparently, reducible to a mechanical process. He will have nothing to say to any internal force directing the energies of matter, such as the Vervollkomnungsbewegung of Nägeli.[120]
“Such an assumption,” he writes, “of a mystic, essentially teleologic force, wholly independent of and dominating all the physico-chemical forces and influences that we do know, and the reactions and behaviour of living matter to their influences which we are beginning to recognize and understand with some clearness and fulness—such a surrender of all our hardly won actual scientific knowledge in favour of an unknown, unproved, mystic, vital force we are not prepared to make.”[121]
The above passage is very well fitted to be the pivot of the whole controversy. We shall examine it therefore in some detail.
It is, in the first place, hardly correct to say that the X factor in life and evolution is supposed by thinkers like Driesch, Reinke, and Nägeli to be ‘wholly independent of’ and to ‘dominate’ all the physico-chemical forces that we do scientifically know. Man, for example, cannot be said to be ‘wholly independent’ of the physico-chemical energies of which he makes use for a multitude of objects. He is very dependent, both on those outside him and those in his own organism. He cannot originate the smallest quantum of physical energy. Yet he is unquestionably capable of directive action upon matter.
In the second place it must be pointed out that the X factor, conceived as it is in this book, though Prof. Kellogg may call it ‘mystic’ if he likes, is certainly anything but ‘unknown.’ There is nothing more mystic than the human spirit—does not mysticism mean the attribution of spiritual significance to material things?—but there is nothing more real and certain. The very act of knowing, however material or mechanical may be the object of knowledge, is an act of the spirit, and we know the spirit itself better than anything else. How did this spirit come into active being? There are only two conceivable ways. Either it was at a certain moment projected into the universe from without by a Supreme Spirit, or it was, like everything else, evolved. If we accept the former view we may say good-bye to science. Miraculous interventions will explain anything, and if we admit them in one case they may be valid everywhere. But if we take the second view, as do practically all men of science, we are bound to admit that spirit had from the beginning some constant and natural relation to matter, for evolution does not work miracles—it cannot make something out of nothing. If, then, we regard Man not as an outside observer of the universe but as an organic part of it—and I believe no thinking about nature can be of any value until we have grasped and fully realized that position—then there can be nothing to surprise us if we find traces of a directive control in the elementary processes of life and development. It would be more surprising if we did not. If we reduce the whole universe, apart from the human spirit, to physico-chemical processes we are at once confronted with the problem of evolving the human spirit out of such processes; and that, on the face of it, is a sheer impossibility. All physical and all chemical phenomena as such are reducible to the movements and groupings of atoms and molecules. These movements and groupings can affect the spirit which finds itself mysteriously implicated in their activity, and the spirit can affect them. But that molecular movements can create spirit is unthinkable by any one who realizes what spirit is and what movement. Rather should we say that in the power of movement, in action, change of any kind, we are to see the evidences of spirit.
We are now in a position to discuss the difficulty raised by Eimer and by Günther, when they point to instances where the supposed psychic force in nature has failed to achieve its end. It fails because, on its mechanical side, it sometimes encounters obstacles which on the psychic side were not provided for. The law of gravitation is a condition of life, but it will kill a man who falls over a precipice. The adaptability of protoplasm is a necessary condition of evolution, but circumstances will occur in which the adaptation means degeneracy for the organism as a whole. Eimer’s argument is good, indeed, against the mythological conception of a supreme Creator, perfect in prescience and in power, who orders the goings-on of the universe from his throne above and outside it. But we seek for no such being in natural phenomena. Perfection is no attribute of anything that operates in Time, and so far as we regard the divine life as working in Time we must regard it as becoming, not as being, perfect. Again, Eimer’s objection shows that he conceives the psychic force against which he is arguing as in itself something mechanical, a mechanized kind of vitality, which ought to achieve its end with a flawless exactitude. Of this, also, nature knows nothing. The universe is what it is precisely because the Power behind its phenomena is neither blind Chance on the one hand nor rigid determination on the other—because it is vital, progressive, and free. This power is certainly capable of making imperfect adaptations and of diverging into false side-tracks of development. That is a fact of much significance, but it is no argument against the existence of such a power—it merely reveals its character. A special study of regressive structures and of the laws and principles which lead to them would have extreme interest, both for biology and for philosophy. But it could not affect the significance of the broad fact that, in a world where the highest living being was once a particle of shapeless protoplasm, we have now Man, a being lamentably unfit, indeed, to be the last birth of Time, but uniquely great by his very consciousness of that unfitness.
In contemplating this wonderful ascending movement let us not forget that the warrant for its continuance rests in ourselves. The false tracks, the regressive forms, which meet us in nature prove at least this: that the line of development which we observe on earth may conceivably end in a disaster which would bear to the course of Life in general just such a relation as the degeneration of the Amazon ants does to life on this globe. We are by no means entitled to sit still and expect that the current of evolution will bear mankind along irresistibly to its goal. With the development of the conscious will we are made responsible for the advance of life in the only sphere which we know and which our actions can affect. Man is, as it were, the growing-point of that progressive life. If his strange passion for the perfection which he has never seen should be smothered in the struggle for mere existence, or corrupted by brutal luxury, then growth will be at an end, atrophy or degeneration will set in. The vision of a nobler, freer, more humane life than is anywhere widely possible on earth at present cannot be realized without the strenuous help of men and women who have learned to subdue the Ego with its fierce egotisms into harmony with the purposes of the divine Whole. But this much we may say—that they will not fight alone. No one ever pursued a high and worthy aim without finding that he had drawn to himself those ‘great allies’ of whom Wordsworth has written so greatly; powers implicit in the nature of the world, and always waiting to be unlocked by the heroic Will.
The Power, some of whose workings it has been attempted to trace in the foregoing pages, is a controlling and directive force, making, through countless varieties of being, for one clear and definable end—the realization of life. It may be asked, Are we to regard this divine Power as wholly immanent in matter or as partly transcending it and governing it from without?
The nature of the divine principle, so far as we are able to discern it, cannot be fully discussed until we come to consider it in the highest sphere of manifestation yet known to us, that of the human soul. But with the question which has just been raised we are now in some measure able to deal, and the consideration of it may bring this section of our study to a close.
In the world of inorganic matter, the tendency of units to form themselves into groups having relation to other groups is already visible. A force immanent in the atom clearly becomes transcendent in relation to the atom when atoms group themselves into molecules. And when molecular affinities come into play, and obey definite laws of form, as in the wonderful phenomena of crystallization, we see that the force immanent in each molecule becomes transcendent, as regards the molecules taken separately, when we look at them from the point of view of the completed group. Crystallization is a process which trembles on the very verge of vital action. And in vital action the alternation of immanence and transcendence in an ever-ascending scale becomes still clearer and more significant. Every cell is a collection of forces controlled by a power which transcends each one of them, or any number of them below the whole. Every cell colony, like the Alga described in an earlier chapter,[122] has a life which is immanent in the colony but transcendent as regards its component members. Definite groups of cells make up the structure of the highly organized plant or animal, and exhibit the same combination of forces immanent in the parts and transcendent, as regards those parts, in the whole. Again, each whole, each individual, is moved by life-impulses immanent in itself but transcendent in so far as they represent the communal life of the species to which it belongs. This communal life of the species becomes immanent again when we regard it as embraced in the life of the totality of beings on the globe. The thought must at once occur, as the ascending series passes out of reach of man’s intelligence: Whither, then, does it lead us in the end? Is there any end? And is our knowledge of Being absolutely limited to those parts of it which lie beneath us?
We are, I think, able, without going beyond the limits of observation and experience, to frame a synthesis of all physical nature, and to express its character in terms of Life and Response. But at the next step we have to embrace man with his moral nature, his intelligence, his personal consciousness, and there may for aught we know be beings far higher than man who must also be included. Now here we are not only in the synthesis and therefore unable to grasp and survey it, but we are also quite unaware of its contents and limits. We ask, Is the All of Things personal? is It conscious? has It a manlike intelligence? and so forth, and I confess I see no way of answering these questions with our present capacities. We can only say—but this is much—that as the universe is one, the part of it which we do not see cannot stand in any essential contradiction to that which we do.
Furthermore we must remember that since, in that aspect of us which observes and studies, we are distinct personalities, we are obliged, in so observing and studying, to regard things as outside of ourselves. This is the core of the whole difficulty. At bottom, the relativity of human knowledge does not depend on the fact that time, space, and causality are, as Kant has taught us, modes of thought imposed upon our ‘I,’ with nothing external answering to them; it goes deeper, it depends on the ultimate fact that I am an ‘I,’ and therefore separate (as such) from what I observe, and therefore only capable of studying my own states as affected by external things, not the very things themselves. Real knowledge, then, must consist in getting out of this prison of ‘I’-hood and entering into actual union with what we observe. Could we do that, we should at once live not in our ‘selves’ but in the Whole. The question then is, whether it is ever possible so to escape, and how?
We must note, however, that no one who has done this could ever tell us precisely what he has done. For the moment he begins to put his experiences into an intellectual form, the laws of the mind reassert themselves, things externalize themselves again, the ‘I’ reappears, the gulf yawns again between subject and object.
And yet the instinctive language of man shows that he does regard it as possible to lose himself in the contemplation of something transcending his powers of ordinary intellectual apprehension. Why should he not? If a transcendent Reality exists, as it must, then the faculty of entering into conscious relation with it is one which Time would surely some day bring to birth.
And although no man, as I have said, can ever express to other minds in terms of the intellect the reality he has thus witnessed, he has found means to do better than this—he can help them to share his vision. These means we call Poetry, Art, and Religion which is the poetry of Ethics. Through these it is that man most truly lives, because united in spirit with a larger life than his ‘self’ and his senses are aware of. Through them it is that while the eye sees the sunrise, the spirit sees the glory, that while the intellect apprehends Truth, the soul is ready to die for it, that while self-interest bands men together in communities for mutual service, Love prompts to the services that will never be recompensed. We are not then, it seems, absolutely imprisoned in our ‘I,’ strait as the bonds may seem. But this must be added, that they will never seem so strait as when we fancy that we can get out of them by any purely intellectual conception of the Ultimate Reality. “God,” says Æschylus most nobly, “is the Air, God is the Earth, God is the Heavens; yea, God is all things, and That which is above them.”[123] There is always a ‘beyond’ for the explorations of the intellect. The function of the intellect is to combine and reduce to order the experiences of sense, thus guiding us with definite aim through the bewildering wonders of life. But let us not dream that it can ever guide us to any goal or terminus. The goal is at once infinitely distant and nearer than our breath and blood. The search for it will last as long as Time. It is of the essence of the view of the universe here put forward that the intellect can never embrace it in any closed system of thought. Turn as we may to one after another of these closed systems as each grows out of harmony with advancing knowledge and insight, the true conclusion, at least for readers who have followed these pages with assent, will be to stand cheerfully ready to renounce all systems, trusting in the last resort to no formulas, but to the play of eternal Powers on the imagination, the heart, the will:—
“They bring none to his or her terminus or to be content and full,
Whom they take they take into space to behold the birth of stars, to learn one of the meanings,
To launch off with absolute faith, to sweep through the ceaseless rings and never be quiet again.”[124]