§ 1. Difficulties in the Way of a Religious Interpretation of Animate Nature. § 2. Extinction of Highly Specialised Types, § 3. Imperfect Adaptations. § 4. Disease. § 5. Parasitism. § 6. Cruelty of Nature. § 7. Senescence and Death. § 8. Apparent Wastefulness. § 9. A Balanced View.
§ 1. Difficulties in the Way of a Religious Interpretation of Animate Nature.
SCIENCE has strictly to do with the operations which go on in Nature. It may legitimately inquire, indeed, into the purposes that prompt the efforts of the higher animals, or into the means by which certain results have been achieved, but it has not to do with the problem of the meaning of Evolution. Metaphorically we have occasionally spoken of the tactics of Nature, notably the great trial and error method of Natural Selection, but we confess that this is leaving strictly scientific terminology. And if the metaphor of tactics be allowed to pass, we must not offend by speaking of strategy. Yet as rational beings we insist on pushing beyond science to a more all-round or synoptic view which inquires into the significance of things and of organic evolution in particular. That organic evolution has led on to Man is certainthe only known organism to understand it a little; the general trend of organic evolution is integrative and towards what at our best we value mostgoodness, beauty, and the health that leads to truth; there is, we maintain, a scientifically demonstrable progressiveness: these and other considerations give us what we may call a scientifically justified expectancy of discovering significance. But it is through other paths of experience that men come to believeif they have the will to believein there being a strategy behind evolution, which is partly what believing in God means. Given, in other than scientific experiences, some conviction of an increasing purpose, ultimately spiritual in content, the question rises whether the state of affairs in Animate Nature and the way in which this has come about is congruent with a religious interpretation.
We repeat that a scientific survey of the system of which we form a part cannot prove anything as to the significance of the whole; that is certainly not its métier; yet it is legitimate to ask whether the impressions afforded by the scientific survey are consistent with regarding Nature as the expression of a Divine Thought or Purpose. But it is often said that this consistency can be recognised only by those who are willing to ignore the seamy side of things. Let us therefore face some of the disharmonies and shadows.
§ 2. Extinction of Highly Specialised Types.
One of the shadows which cannot be ignored is the lack of plasticity in highly specialised types. The physical world is changeful, in climate, in weather, in surface-relief, and there are many living creatures which are unable to change with it. They have gone too far to tack, and they perish. Adaptations to novel conditions abound, but the over-specialised are sometimes victims of their own perfection. Many types of great excellence have thus passed away without leaving any direct descendants. The graceful Graptolites, the robust Trilobites, the highly specialised Eurypterids, the great Labyrinthodonts, Ichthyosaurs, Plesiosaurs, and the Pterodactyls that could fly, are such lost races, not continued into other stocks, wonderful achievements, but lacking in plasticity. As the palæontologist Marsh said, the epitaph of the Iguanodon might be, I and my race died of over-specialisation, and he might have added and stupidity, for there was not in these ancient giants the intellectual resourcefulness which we see in the still more specialised modern birds who can adapt themselves to many a drastic change.
We must admit that the extinction of splendidly perfect types raises strange thoughts. What can one say save that every art is limited by its medium, and that here the medium is twofold, the inorganic and the organic? The inorganic world is the grindstone on which life has been whetted, and it cannot become a soft cushion. An environment without vicissitudes might have meant an unprogressive fauna and flora of jellyfishes and seaweeds. Against the callousness of the inorganic domain, moreover, we should remember, though with dread of a circular argument, the other fact that the physical conditions are singularly well suited to be a home of living creatures. Moreover, the lack of plasticity in organic structure is the minus side of that stability which marks the journey-work of millennia. What is stable cannot also be labile. Furthermore, some of the gains of lost races may be continued on collateral lines.
§ 3. Imperfect Adaptations.
Another shadow is the existence of imperfect adaptations. These are of two kinds. First, there are established arrangements which work well on the whole, but now and again break down or miss the mark, as is the case with tropisms and instincts that are in ninety-nine situations adaptive, but in the hundredth suicidal. The crepuscular moth, unaccustomed to light, flies into the candle, and the lemmings on the march seeking new territory swim out into the North Sea and are drowned in thousands. But the most keen-scented discoverer of disharmonies or dys-teleologies will surely not suggest that organisms should be adapted for unusual exigencies rather than for the routine of daily recurrence. Even when there are adaptations to peculiar exigencies, as we see in the surrender of damaged parts and their regrowth, these exigencies are of frequent recurrence.
There are instances, however, of structures that do not seem to work so well as we have got into the way of expecting from organisms. Thus attention has often been directed to the cumbersome twenty feet of intestine with which man is burdened without corresponding compensation. It may be doubted, however, whether much of a case can be made of any of man's disharmonies, since he is evidently in process of rapid change of habits. An organism originally adapted to feed when he could rather than when he would, must not complain too loudly if he is not perfectly adapted for absolutely punctual and well-proportioned meals.
In the case of some trees which spread their roots horizontally at a slight depth it not infrequently happens during a storm that the pressure of the wind on the branches causes a strain too great for the roots to stand. The tree falls, though in perfect health. This violent death reveals an undoubted imperfection, but it also shows how physical conditions eliminate such subtle defects as lack of proportion between spread of sail and strength of mast.
§ 4. Disease.
Those who would arraign Nature on the charge of tolerating disease may be almost dismissed from court. For, apart from parasites and senescence, there is almost no disease in wild Nature. Should a pathological variation arise, and that seems a rarity, it is eliminated before it takes grip. Disease in the system of Nature is a contradiction in terms. Constitutional disease is the occurrence of a metabolism out of place, out of time, and out of tune, and Nature makes short work of such idiosyncrasies.
What, then, of potato disease and salmon disease, of fowl cholera and swine fever, of big-bud on our currant-bushes and bee-disease in our hives? The list may be lengthened out, but the answer is the same for all, that these diseases occur in artificial, humanly contrived conditions, not in the system of wild Nature with which we are here concerned. It is doubtful whether there are more than two or three examples of microbic disease in natural conditions, one of the best known being a bacterial disease in sandhoppers, and this may have something to do with sewage, as salmon-disease with polluted rivers.
It is not asserted, however, that wild animals may not be infected with microbes so that an epidemic results. What is maintained is that such occurrences are exceedingly rare and transient, and that they are usually traceable to rapid human interference,to introducing new tenants into a region, to killing off the natural eliminators of the sickly, to permitting over-crowding, to an infection of the soil and water, and so forth.
What of a familiar case such as grouse-disease? The facts appear to be that grouse harbour a good many parasites which normally do them no appreciable harm. When birds of inherently weakly constitution appear they are normally eliminated by golden eagles, stoats, and other natural enemies; and the standard of the stock is not lowered. If over preserving, i.e., careless elimination of the natural enemies, removes the natural sieves, then birds of weakly constitution tend to become more numerous with each year, till a bathos of weakness is reached. The contingent of parasites which seems to be kept within limits in the vigorous bird may then increase sevenfold, spreading, for instance, to new organs, and this may give the death-blow. It seems that there is no specific disease in this well-nigh sacred bird, and it is highly probable that there would be no grouse-disease if there were no game-keepers.
§ 5. Parasitism.
One of the shadows on the pleasant picture of animate nature is the frequency of parasitism. To some minds it appears as a blot spoiling the whole script. But without denying that there is some warrant for practical, æsthetic, and ethical recoil, we think that much of this is due to lack of perspective. Let us briefly consider the facts of the case.
(a) Thousands of living creatures live in or on others, bound up with them in brutally direct nutritive dependence, and incapable of living in any other way. Uninvited and non-paying boarders they are, who make their hosts no return for the hospitality enjoyed. Most animals that have bodies at all have parasites in or on them, and the same is true of most of the higher plants which are the hosts of moulds and rusts, gall-producing creatures, and burrowing larvæ. One of the European oaks harbours no fewer than ninety and nine different kinds of gall-flies, and the hundredth is probably being discovered. The lac insect of India is attacked by thirty-one species of plant and animal parasites. The dog is a terrain for over forty parasites; man and pig have far more. In fact when we inquire into the number of diverse parasites that may possess a lusty host, with a wide range of appetite, we find that they are legion like the demons. When we ask about the number of individual parasites, it is beyond telling.
(b) In many cases the association of parasites and host is very specific, that is to say, many a parasite is only known to occur in one definite kind of host, and many a host is curiously non-susceptible to parasites not very different from those which it harbours. The larvæ of some of the fresh-water mussels cannot become parasitic except on definite species of fishes, though the Iarvæ of some other kinds can utilise many fishes. The larva of the liver-fluke in Britain cannot develop except in one species of water-snail (Limnæa truncatula), though in other countries other species sometimes serve. There are, however, some very cosmopolitan parasites which occur in many hosts.
(c) Parasitism is a relation of dependencealways nutritive, often morebetween the parasite and the host, but it occurs in many grades. There are superficial ectoparasites which often retain great activity, and intimate endoparasites which may become practically part of their host. There are partial parasites which retain independence during some chapter or chapters of their life, and total parasites which pass from host to host and are never free. Sometimes, it is only the female that is parasitic, the male remaining free.
(d) Corresponding to the degree of parasitism is the degeneration of the parasite. This is sometimes to be witnessed in the individual lifetime, e.g., in many Copepod Crustaceans where the young are free-living. In other cases it may be inferred by comparing the parasite with related free-living types. The retrogression affects especially the nervous, sensory, muscular, and alimentary systems. The reproductive system is often highly developed and the multiplication very prolific, which, may be associated (a) with the fact that the parasite is often living without much exertion, with abundance of stimulating food at its disposal, and also (b) with the probability that as the chances of death are often enormous, non-prolific forms have been persistently eliminated. Parasites survive not because they are strong, but because they are many.
(e) While there are many different types of parasites, it is of interest to notice that some kinds of organisation are not compatible with a parasitic mode of life. Among back-boned animals the only parasite is the hag (Myxine) and it is not thoroughgoing. There are very few parasitic Molluscs or Coelentera, and there are no parasitic Echinoderms, partly perhaps because the life of these three types is very dependent on the activity of ciliated cells which usually require fresh water-currents. Among plants, most of the parasites are Fungi and very few are Flowering Plants.
(f) The life-histories of parasites are often very intricate and full of risks. In many cases two hosts are required. The embryos of the liver-fluke pass from sheep to water-pool; the hatched larvæ enter a water-snail; there are several asexual generations in this first host; minute flukes leave the snail and encyst on blades of grass; if these are eaten by a sheepthe second hostthe cycle recommences. There are curious cases of hyper-parasitism where one parasite contains a second which contains a third, and this gives rise to complicated life-histories.
(g) Thoroughgoing parasites, with a long evolution behind them, are naturally enough well-adapted to the conditions of their life. Thus a tapeworm in the intestine of its host absorbs food by the whole surface of its body; it has muscular adhesive suckers and sometimes attaching hooks; it can thrive with a minimum of oxygen; it has a mysterious anti-body which prevents it being digested by its host; it is exceedingly prolific; and it is self-fertilising. The tapeworm may be ugly, but it is very well-adapted; it may be repulsive, but in the technical biological sense, relative to the given conditions, it is fit.
Such are a few of the most important facts in regard to parasitism. Let us now inquire why the prevalent inter-relationship seems to many a dark shadow. Parasitism is repulsive for three reasons: (1) because we dislike to see fine organisation devastated, (2) because many parasites produce an unpleasant æsthetic impression, and (3) because the life of ease and sluggish dependence grates on our ethical sense or on our idea of an organism.
Many people resent the fact that a contemptible microbe may kill a genius before he comes of age, and that paltry flies put a drag on the wheel of the chariot of civilisation. It is abhorrent that fine organisation should be spoiled by intrusive parasites, but it is necessary to look all round the facts. (a) In a multitude of cases the parasites do not greatly trouble their hosts, a modus vivendi has been established. If the host be of a weakly constitution or enfeebled by lack of food, the parasites hitherto trivial may get the upper hand and bring about the death of the host. But this sifting will make for racial health, and cannot be called abhorrent (b) Mortality from parasites is in most cases a consequence of organisms entering a new area and becoming liable to attack by creatures to which they can offer no natural resistance, or a consequence of the introduction of the parasite into a new area where it finds new hosts abnormally susceptible to it. Cattle introduced into a tsetse-fly belt are fatally infected by a trypanosome which does not seem to damage the native antelopes in which it is, so to speak, at home. The fatality of a new microbe introduced into a new population is familiar, as in the case of the Black Death in England, which was due to the introduction of the microbe of bubonic plague.
It must be remembered that the effect of the parasite on the host is extraordinarily varied. Some give off toxic substances; others cause lesions and inflammation, especially if they stray from their usual habitat in the body; some promote beautiful growths like oak-apples and pearls; others drain the food-supply; some do very little harm. The sturdie-worm causes locomotor disorders in the sheep in whose brain it grows, but the Gregarines found in the reproductive organs of most earthworms seem usually unimportant in their effects. The parasitic crustacean known as Sacculina destroys the reproductive organs of crabs and changes the male constitution towards the female type, so that a small ovary may develop. The shape of the crab's abdomen changes, approximating to that of the female, and the protruding parasite is actually guarded by its bearer as if it were a bunch of eggs. But many fish-lice seem to do very little, if any, harm to their bearers. It is highly probable that very aggressive parasites have eliminated themselves from time to time by killing their hosts, which it is not to a parasite's interest to do.
(c) It seems useful to place by themselves parasites like virulent Bacteria (e.g., the Plague Bacillus) and virulent Protozoa (e.g., the Trypanosome of Sleeping Sickness) which are rapidly fatal when transferred to a new kind of host. Thus the Plague Bacillus is transferred by the rat-flea from the rat, who can stand it, to man who has no constitutional defence against it. Similarly, the tsetse-fly transfers the trypanosome from some immune wild animal (such as an antelope, it may be) to the highly susceptible man. But these microbes are not in any special way adapted to parasitic life; they might as well be called predatory. Many predatory parasites, like Trypanosomes, live an exceedingly active life within their host, exerting themselves as much as many a free-living creature.
Many parasites are æsthetically repulsive in form, colour, and movements, and it is interesting to contrast the attractive free stages of some of them with the ungraceful bloated parasitic stages. As we have already seen, the ugliness is the brand of their degeneracy. It is the natural result of retrogression, sluggishness, and over-feeding. The life of ease drifts and it loses the grace of the sharpened life which commands its course. The dodder and mistletoe, which every one must admit to be beautiful, are, it is interesting to notice, only partial parasites. The ugliness of some parasites is perhaps an exception that proves the rule; it is as if Nature said: This asylum is open, if you will, but if you enter, you must wear the livery of dishonour; beauty will disappear.
To many minds, however, the darkness of the shadow is in the inconsistency between the parasitic mode of life and Nature's usual insistence on a strenuous life, and this has to be admitted. But one must remember how parasitism arises in the struggle for existence. Environing limitations and difficulties press upon the organism and one of the solutions which is open to many is to evade the struggle by becoming parasitic. The struggling, endeavouring creature cannot have a clear prevision of the facilis descensus it has set foot on. It may try to survive inside a larger organism which has swallowed it; in its searchings for food and shelter it may discover what is to it simply a new worldon or beneath the surface of another organism. It is not another organism to them as it clearly appears to us; it cannot be separated off from other areas of safety and abundance which other struggling organisms may secure.
It is exceedingly difficult to draw a dividing line between some parasites which are of some slight use to their hosts, e.g., the beautiful Infusorians in the stomach of some herbivores like horse and cow, which seem to help in breaking down the food, and certain symbions or commensals which are on the whole useful, but levy a slight tax. Some ectoparasites behave as if it was their duty in life to keep the surface of their host's body clean. All the three modes of life are to be looked at as expressions of the widespread tendency in Animate Nature to establish inter-relations between organisms, to link lives together, to weave a web of life. It may be occasionally repulsive, but it is to be considered broadly as a part of a complex external systematisation or correlation that has been evolved in the course of ages and is of great importance in the process of Natural Selection.
It must not be forgotten that parasites occasionally play a part as eliminative agents, and may work towards conservation as well as wastefully. They may weed out the weakly members of a stock. They may put a useful check on abrupt changes of distribution. Another exonerating fact is that in a number of cases, e.g., among Crustaceans, the parasitism is connected with the continuance of the race, and is altruistic as much as egoistic, for it is confined to the mother-animals, who seek a safe place in which to bring forth young.
It must be admitted that there is an occasional hint of wildness about parasitism, just as about some other ways of life. No explanation can be offered except that organisms have in them something akin to the artist's genius. They have endless resources and they are free. Some have explained that it is not the destructiveness of parasites they object to, nor their ugliness, nor even their feckless drifting life, but their devilishness. The ichneumon-fly lays her eggs in a caterpillar; the hatched grubs feed on the living tissues; they make their way out to begin a new phase of life after they have killed their host. It is very difficult, however, to avoid anthropomorphism in such cases. Perhaps it does not matter much to the caterpillar whether it is devoured from the inside or from the outside, and perhaps the ichneumon larvæ should rather be called beasts of prey than parasites. In any case it is certain that what the ichneumon-insect does to the caterpillar is not so repulsive as what man often does to man, for man knows or should know what he is doing. In both cases there is devilry, but the ichneumon's is unconscious. Moreover, it plays a very important rôle in the extraordinarily well equilibrated economy of Nature.
§ 6. Cruelty of Nature.
The system of Animate Nature is evolved on the scheme that many kinds of living creatures use others as food. If this be cruelty, then Man is in it too. But in most cases there is no reason to drag in the idea of cruelty; taken in the strict sense the word does not and cannot grip.
It should be remembered, if it makes any difference, that many animals are vegetarian and that many depend upon organic débris. Thus great hordes of marine animals live on the detritus washed outwards and downwards from the littoral vegetation of Algæ and sea-grass. That all living creatures should have pursued the plant régime of living on air, water, and salts is conceivable, but it would not have been an adventurous resolute world, for the vigorous higher life depends on a supply of high explosives manufactured by other creatures. If animals had had to manufacture their own munitions as plants do, there would not have been much fighting, but there would not have been much thinking either.
But the critic of Nature explains that it is not the carnivorousness that offends him,he does a little in that way himselfit is the manner of its accomplishment. The gentle disciple of Izaak Walton is pained that the Fishing-Frog should use a rod and line. The housewife who sets a trap for mice in the pantry affects to shudder at the ant-lion which makes a pitfall for unwary insects. There is a taint of insincerity about all this exotic tender-heartedness. The joy of the cat is the grief of the mouse, says a Russian proverb; but we go a-fishing with a light heart. We are of more value than many trout. We do not deny that there are some difficult cases, like that of the cat playing with the mouse, which has perhaps an educational significanceand what may not be done in the name of educationbut in the great majority of cases violent death is rapid and probably painless, and the accusation of cruelty is an irrelevant anthropomorphism. We do not deny that there are what look like dark shadows in Animate Nature, but we have seen some of them disappear in the light of fuller knowledge, and we think that William James was on the whole misled by unawareness of the facts, when he wrote of Natureto some of us an alma materas a harlot, all plasticity and indifference, a moral multiverse and not a moral universe. Beauty and hideousness, love and cruelty, life and death keep house together in indissoluble partner ship; and there gradually steals over us, instead of the old warm notion of a man-loving Deity, that of an awful power that neither hates nor loves, but rolls all things together meaninglessly to a common doom. But this seems to us a terribly alarmist inference to base on a demonstrably inaccurate study of Animate Nature. It is not really the case that beauty and hideousness, love and cruelty, keep house together in indissoluble partnership.
We must confess, however, that even the naturalists are often against us. Thus the veteran John Burroughs writes in his charming Breath of Life: What savagery, what thwartings and delays, what carnage and suffering, what an absence of all that we mean by intelligent planning and oversight, of love, fatherhood! Just a clash of forces, the battle to the strong and the race to the fleet. Are we not all like perplexed privates writing bitterly of a campaign, knowing little of the actual operations, still less of the tactics, and nothing of the strategy? There are no doubt terrible minutes when two lions get the better of an antelope, or the wolves close in upon the deer, and huntsmen like Selous have spoken of the frenzy of fear and agony of a dying brute. But we must beware of anthropomorphic exaggeration. We recall Mr. Louis Golding's good-humoured rebuke (1919):
But if a moth should singe his wings,
The world is black with dismal things.
And if a strangled sparrow fall,
There is not any God at all.
Alfred Russel Wallace had wide experience of wild nature, and wrote: Animals are spared from the pain of anticipating death; violent deaths, if not too prolonged, arc painless and easy; neither do those which die of cold or hunger suffer much; the popular idea of the struggle for existence entailing misery and pain on the animal world is the reverse of the truth. Similarly Darwin concludes his chapter on the Struggle for Existence with the sentence: When we reflect on the struggle, we may console ourselves with the full belief that the war of nature is not incessant, that no fear as felt, that death is generally prompt, and the vigorous, the healthy, and the happy survive and multiply.
We must beware of anthropomorphic exaggeration, but we must also beware of commonplace inaccuracy. The death-crisis of a mouse killed by a rattlesnake was 13 seconds; the death-crisis of a thrush killed by a golden eagle was less than half that.
We frankly admit, however, that for some reason or other many of the forms of life are weird and fantastic creations, and there is often more than a hint of the wildness of which Prof. William James spoke. The solitary wasp Philanthus, known as the bee-eater, catches bees and after giving the victim a knock-out blow beneath the chin and paralysing it, proceeds to knead its anterior body, squeezing out the honey from the crop and enjoying the grim meal. But if instead of turning away repelled we follow the Philanthus, we find that the body of the bee is used as provender for the larvæ whose hatching the Philanthus does not survive to see. We may rest satisfied with this without following the famous entomologist who has told us that the kneading operation which squeezes the honey out is not so much for the parent's immediate gratification as to prevent the larva from having stomachache.
§ 7. Senescence and Death.
Another shadow is senescence and death. It saddens us to see a fine edifice falling into ruins, and though old age is often beautiful in mankind, the time comes when even beauty goes. Let us recall the picture which we owe to the author of Ecclesiastes: The mind and senses begin to be darkened, the winter of life approaches with its clouds and storms, the armsthe protectors of the bodily housetremble, the strong legs bow, the grinders cease because they are few, the apples of the eyes are darkened, the jaws munch with only a dull sound, the old man is nervously weak and startled even by a bird's chirping, he is afraid of even hillocks, his falling hair is white as the strewn almond blossoms, he drags himself along with difficulty, he has no more appetite, he seeks only his home of rest, which he finds when the silver cord is loosed or the golden bowl broken.
There is something indescribably pathetic in the decline and the decay when it passes beyond senescence into senility. The bones become lighter and less resistant, the muscles weaker and stiffer, the nervous system slower and less forceful, the heart less vigorous, the arteries less elastic, the parts fail to answer to one another's call, and then, from hour to hour, we rot and rot.
In regard to this dark shadow, it must first be pointed out that the securing of a healthy old age is very largely within man's control, everything depending on the nature of our physiological bad debts. Many are successful in securing an old age such as Cicero praised; others have one whose days are labour and sorrow. In recent times, the late Professor Metchnikoff has been prominent in maintaining that if man led a more careful life, and had a more enlightened understanding of the limitations and disharmonies of his constitution, he would no longer, as Buffon said, die of disappointment, but would attain everywhere a hundred years.
The second point is not less important. As Professor Humphrey, a specialist on old age, has said, Strange and paradoxical as it may seem, this gradual natural decay and death, with the physiological processes which bring them about, do not appear to present themselves in the ordinary economy of nature, but to be dependent upon the sheltering influences of civilisation for the opportunity to manifest themselves, and to continue their work. The fact is that man and some of his domestic animals have almost a monopoly of senility, while wild animals rarely show a trace of it. Thus senility is not disharmony in Nature, but in the Kingdom of Man.
The bathos often seen in man is due partly to the way in which he shelters himself from violent or extrinsic death, which cuts off so manyif not mostanimals; partly to the unnatural ways in which he lives; and partly to his deficiency in the resting instinct.
It is instructive to probe the matter further, inquiring into the reasons not for senility, but for senescence and natural death. There is an obvious distinction between (a) death due to microbes or parasites, (b) death due to extrinsic agencies or violence, and (c) death due to internal constitutional reasons; it is with the last, natural death and its antecedent senescence, that we have to do. To the question: Why should an organism grow old?, many answers have been given. A reason has been found in the wear and tear of parts, especially of elements like nerve-cells, which do not in higher animals increase in number, nor admit of renewal, after early stages in development. We do not get any additions to our nerve-cells after birth. But why might not nerve-cells have retained the power of regeneration that they have in some of the lower animals?
A reason for old age and natural death has been found in the slow accumulation of poisonous waste-products, of the results of incomplete combustion, of the results of bacterial activity, and so on. The fire of life may be smothered in its own ashes. But it must be recognised that there is no necessity for this, that we can conceive of more perfect arrangements for purification. Isolated pieces of tissue can be kept for a long time living if waste-products are carefully eliminated.
Similarly it has been pointed out that ageing is associated with the diminishing activity of glands of internal secretion, with a cumulative disproportion between cytoplasm (cell-substance) and nucleoplasm, with the occurrence of organically expensive modes of reproduction, and so on. But these suggestions seem to disclose what are merely symptoms of some more fundamental imperfection.
What that is may be discovered by asking whether it is really the case that all living creatures grow old and die. We know that an insect may live for days, another for weeks, another for months; that a fish may live for years, man for scores of years, and a Big Tree for centuries; but are there any creatures that need not die? It seems that natural death is more or less successfully evaded by most of the Protozoa, which, being unicellular or non-cellular, have no body to keep up, which have very inexpensive modes of multiplication, which can continually recuperate their wear and tear. There is good reason to suspect that the same is true of multicellular animals like Hydra and Planarian worms.
The clearest statement of the problem has been given by Prof. C. M. Child in his Senescence and Rejuvenescence. The process of progressive differentiation or complexifying involves the accumulation of relatively inactive constituents in the living matter. It becomes necessary to have stable frameworks, and it is difficult to keep these young. The vital current deposits materials in its flow, and the bed begins to slow the stream. There are always processes of rejuvenescence at work, removing the relatively inactive material, and re-accelerating the rate so that fresh erosion occurs. All sorts of devices are resorted to, which secure rejuvenescence; many of them are very drastic, such as periodically breaking the body to bits and beginning afresh; but the tendency is for rejuvenescence to lag in the higher animals and for senescence to win. It cannot be otherwise. Death was the price paid for a body; senescence is the tax on specialisation. In the very simple organisms the stable mortal parts of the colloidal substratum, which is life's laboratory, can be reduced and restored piecemeal, and the creature never grows old. Perhaps the same is true of the fresh-water polyp, which thus will have, besides its indifference to wounds, another reason for being called Hydra. But as life became more worth living, and the organism more of an agent, the capacity for rejuvenescence was limited. Thus, as Professor Child tells us, For his high degree of individuation man pays the penalty of individual death, and the conditions and processes in the human organism which lead to death in the end are the conditions and processes which make man what he is. Thus one may perhaps say without irreverence that science has made the shadow of death more intelligible.
What have we, then? At the foot of the scale there are some organisms in which rejuvenescence keeps pace with senescence, and natural death is evaded. At the top of the scale there is the senility of many men and of some domestic animals, like horses and dogs. It is certain that senility is not within the scheme of Animate Nature apart from Man. For many wild animals there is normal senescence, for many there is not even that. There is a slight lowering of vitality and a slight environmental buffet sends them off the stage. But why is it that the fish Aphia pellucida lives only for a year, dying off like an annual plant, while others live for many years? The probability is that the duration of life is limited to some extent by the constitution of the creature, but that within these limits it has been regulated in adaptation to the conditions of life, that it has been punctuated in reference to large issues, namely the welfare of the species. Not that there is any purposive adjustment, but simply that for each set of given conditions there is an effective age which becomes the age of the surviving types. It is not difficult to understand that a variation in the direction of longevity might be very unprofitable and would be certainly eliminated by the gradual disappearance, paradoxical as it may seem, of the long-lived type. For the longevity might mean that the organism continued multiplying when it was past its best and thus impaired the vigour of the stock. The longevity might mean that the organism continued multiplying after it had suffered so many dints from the years that it could no longer give the offspring a successful send-off in life. Such variations condemn themselves literally, and the length of life is by selection adaptively punctuated towards the welfare of the race. In some of the higher organisms prolonged multiplication is constitutionally prevented on the female side after a certain age is reached, and that is also adaptive. This idea must be gently transferred to human life. Apart from multiplication altogether, apart also from senility, which is often avoided with masterly success, it seems in Man's case very doubtful that it is for the good of the race that longevity should become too pronounced a habit. There is profound wisdom in Goethe's saying that Death is Nature's expert device for securing abundance of life.
§ 8. Apparent Wastefulness.
Another shadow is the apparent wastefulness. So careful of the type she seems, so careless of the single life. The abundance of life has its correlate in the abundance of death. What a book, Darwin wrote, a a devil's chaplain might write on the clumsy, wasteful, blundering, low and horribly cruel works of nature! (More Letters, Vol. I., p. 94, 1856). But we doubt whether he would have written this a quarter of a century afterwards, when his insight into the economy of Nature had grown clearer. We need not doubt, for in 1881 he wrote: If we consider the whole universe, the mind refuses to look at it as the outcome of chancethat is, without design or purpose (More Letters, Vol. I., p. 395, 1881).
Wastefulness is rather a question-begging epithet. The abundance of small fry has made the life of higher creatures possible. We do not say that the purpose of water-fleas is to feed fishes, any more than we say that the purpose of certain fishes is to feed man. What we say is that the extraordinarily prolific multiplication of humble organisms affords a stable foundation on which a higher life has been built. The number of free-swimming larvæ in the waters is beyond our powers of picturing, and we think too little of the wonder of this everyday multiplication which is so different from anything in the inorganic world. Only a fraction of these larvæ come to anything, but since they form the sustenance of finer expressions of life, we see no reason to speak of wastefulness. The scheme of Animate Nature is in part a cycle of incarnations; we may not approve of the scheme, but it is not a wasteful one. In this connection it may be observed that it is a misrepresentation to speak, as Professor Hobhouse does, of the result of evolution being that Species should learn to destroy each other more efficiently, for this disguises two facts,(1) that huge numbers of animals live on detritus, which is often produced by physical agencies; and (2) that what very frequently happens is the establishment of a modus vivendi which lives and lets live. But our general point is this, that a certain security as regards the means of subsistence is a condition of economising reproductivity in higher animals, which means the recognition and development of personality. Is wasteful the term to apply to the existence of that teeming organic proletariat which is one of the primary conditions of personalities?
The view that there is a deep incongruity between the facts of the case and the possibility of religious interpretation has been forcibly stated by Professor Lovejoy, who does not, however, accept the conclusion. Darwinism or the doctrine of natural selection declares these three unlovely aspects of the worldits wastefulness, its disharmony, and its crueltyto be not simply casual details of the picture, but the very essence of that whole evolutional process which, regarded in its results and not in its methods, had seemed so admirable and so edifying to contemplate (Lovejoy, 1909, p. 93). Whether the seamy aspects of Nature which the theory of natural selection is supposed to bring into relief are really centrally significant and ubiquitous aspects, is, Professor Lovejoy admits, a question which contemporary biology is diligently endeavouring to settle by its own proper methods. One can only say now that the dominant tendency is distinctly towards an answer in the negative (1909, p. 95). We have tried to show that this dominant tendency is reasonable.
§ 9. A Balanced View.
These are not all the shadows by any means, but they must serve for illustration. In other studies we have seen that the struggle for existence is often an endeavour after well-being; not a miserable internecine squabble around the platter of subsistence, but including all the answers-back which able-bodied, able-minded creatures make to environing difficulties and limitations. We have seen that natural selection is neither altogether automatic nor in any case arbitrary, but is a discriminative sifting in relation to an established Systema Naturæa fact which helps to secure progressiveness. We have seen that variation is not haphazard nor fortuitous, and that heredity does not leave us stifling in a fatalistic atmosphere. We have seen that beauty is Nature's universal hall-mark on fully-formed, independent, healthy organisms, living in natural conditions. And lastly we have seen that many of the shadows become less perplexing when carefully scrutinised.
Our thesis is violently opposed to the view of some of the greatest thinkers. Aristotle, who knew Animate Nature with an intimacy insured by his genius and patience, spoke of the lack of order in Nature and likened it to what may be seen in the life of a slave, to whom, on account of his low estate, certain license is permitted. Hegel, to skip about two millennia, compared Nature to a Bacchantic dance. We regard both comparisons as infelicitous. Indeed, we are not in the least inclined to accept the depreciatory views of Animate Nature which have been put into circulation. Many are obvious libels. There is some truth in Aristotle's dignified caution that Nature is dæmonic rather than divine,but we reject as ignorant and impious Luther's brusque saying: The world is an odd fellow; may God soon make an end of it. Is it unreasonable to suggest that those who allow themselves to be oppressed by the discords and disharmonies in the world without are in part themselves to blame for the weight of their burden, by remaining, more or less consciously, under the domination of the geocentric, anthropocentric, and finalist pre-conceptions of the Middle Ages, which regarded Man as the hub of the Universe?
In reference to the misery of catastrophes, like the Calabrian earthquake or the Titanic wreck, we venture to note how the apologetic problem changes with our changing outlook on Nature. Not many generations ago these calamities were directly and literally referred to the hand of God under the conception of the reign of law such acts are now regarded as acts of divine permission rather than of commission. No sceptic would write of them now as Voltaire did of the Lisbon earthquake. Moreover, every one feels that it is not an orderly Universe if the laws of the strength of materials or of oceanic currents can be abrogated by mercy for individual lives. Without accepting an exaggerated view of the Uniformity of Nature as absolute, we know that within certain temporal and spatial limits we can trust to the regularity of frequently observed sequences. It would be an intolerable world if there were loopholes for individuals even when the number of lives lost is tragic beyond any words. Many speak, rightly we believe, of the unity of purpose working in Nature and its evolution, but do not the tragedies show us plainly that this word Purpose, though the best we have, must be used in this connection in a symbolic way, being Purpose with a plan larger than we can understand?
If our view of Animate Nature presented no difficulties, it would be justly regarded with suspicion. Truly, it presents difficulties. There is often lack of plasticity; there are imperfect adaptations; there are taxes on progress; there are many parasites; there is some suffering and many a domestic tragedy; there is the astonishing spectacle of the demolition of masterpieces that millions of years have gone to fashion; and there is often a note of wildness that startles us. No one can shut his eyes to the difficulties, our protest is against allowing them to blot out the sun. The plasticity, the adaptations, the progress, the inter-linkages, the joy, the happiness, the masterpieces, the note of gentleness, how they make the shadows shrink! Our thesis stands that the facts of an accurate Natural History are not incongruent with an interpretation of Nature in higher terms.
We have, moreover, to bear in mind that the evolution is still in progress, that organisms are still subduing the inorganic unto themselves, that the mind-body is still continuing its arduous task of subordinating the body-mind to its purpose, that we in facing and mastering difficulties are sharing in working out a better future for our successors. The ladder of evolution is often very steep and organisms may slip down into disintegrative phases, but the bigger fact is that the main trend of evolution is essentially integrative. Who shall impiously prescribe its limits, especially in the Kingdom of Man, where Personality seems to be beginning to transcend Organism?
It is a defensible position that Animate Nature and its evolution are congruent with a spiritual or religious interpretation. A scientific view of the system of which we form a part cannot, indeed, prove anything about the value or significance of Nature, but it is not inconsistent with the idea that Nature may be a Divine creation. Perhaps this is even suggested by the beauty, the harmony, and the progressiveness of Animate Nature. But there are many shadows.
There is a notable lack of plasticity in highly adaptive organic structure, and if environmental conditions change, highly specialised types may perish because of their very perfection. Only in intelligent resourcefulness is there a way of escape. But every art is limited by its medium, and the extinction of types is often the nemesis of their long-continued stability. Moreover, the external vicissitudes have doubtless had a very important rôle in organic evolution. And even though lost races leave no direct descendants, some of their gains may be continued on collateral lines.
There are some cases where arrangements that are usually well-adapted are fatally inadequate in a crisis, as when the moth flies into the flame or the lemmings swim out into the sea. But adaptations must be, on the whole, in reference to normally recurrent routine, not in reference to very exceptional conditions; though as a matter of fact there are some adaptations which meet rare difficulties. Imperfection of adaptation is often illustrated when organisms are changing their habits or their habitat, and it would be a magical world if it were not so.
It is quite futile to try to make a cosmic shadow out of the frequency of disease. In natural conditions constitutional disease is unknownif it arises it is not allowed to grip; and microbic diseaseso common when Man interferesis exceedingly rare in wild life.
Another shadow is the frequency of parasitism. Parasitic plants and animals are legion and almost no living creature escapes them. It is abhorrent that fine organisation should be spoilt, but many parasites do their wonted hosts very little harm. Many parasites are repulsive in form, colour, and movementsthe brand of their degeneracy. The drifting life of ease seems inconsistent with Nature's way of putting a premium on strenuous endeavour. But parasitism is, to begin with, a response to environing difficulties and limitations, the parasite can have little awareness of the significance of its step; its host is in moat cases simply a promiseful area of exploitation; the parasitism often fades into symbiosis and commensalism; it is often resorted to by the mothers seeking a safe place for the young; it sometimes has a useful eliminative influence. That there is sometimes a hint of devilry in parasitism must be admitted, but there is great risk of fallacious anthropomorphism here.
Another reproach hurled at Nature is that of cruelty, which may be discussed along with parasitism since it refers to the nutritive chains that bind organisms together. That many animals prey on others is obvious, and this must sometimes involve suffering. Yet little is known of their pain, and, apart from a few difficult cases, there is no torturing.
Another shadow is that of senescence and death, But senility at least is not a disharmony in the realm of organisms, only in mankind. Growing old is a necessary tax on differentiation, for as a stable framework grows in complexity processes of rejuvenescence are bound to lag. In some simple creatures natural death is successfully avoided. The conditions and processes in the human organism which lead to death in the end are the conditions and processes which make man what be is.
Oppressive to many is the apparent wastefulness. But the abundant multiplication of humble organisms affords a stable foundation on which a higher life has been based, and a truly marvellous working equilibrium wrought out. The scheme of Animate Nature is in great part a cycle of incarnations; it may attract or repel us, but it is not wasteful.
That there are shadows is admitted, but it is significant that they tend to disappear in the light of increasing knowledge. They do not force us to conclude that there is any radical incongruity between a scientific description and a religious interpretation of Nature.