Part 7 (2/2)

It is usual to speak of the ”all-sufficiency of natural selection,” yet the champion of the selection-theory admits, as he needs must, that the struggle for existence and selection can of themselves create absolutely nothing, no new character, no new or higher combination of the vital elements; they can only take what is already given; they can only select and eliminate among the wealth of what is offered.(38) And the offerer is Life itself by virtue of its mysterious capacity for boundless and inexhaustible variability, self-enrichment and increase. The ”struggle for existence” only digs the bed through which life's stream flows, draws the guiding-line, and continually stimulates it to some fresh revelation of its wealth. But this wealth was there from the beginning; it was, to use the old word, ”potential” in the living, and included with it in the universal being from which life was called forth. The struggle for existence is only the steel which strikes the spark from the flint; is, with its infinite forms and components, only the incredibly complex channel through which life forces its way upwards. If we keep this clearly in mind, the alarming and ominous element in the theory shrinks to half its dimensions.

And, finally, if we can rid ourselves of the peculiar fascination which this theory exercises, we soon begin to discover what extraordinary improbability and fundamental artificiality it implies. ”Utility” is maintained to be that which absolutely, almost tyrannically, determines form and development in the realm of the living. Is this an idea that finds any a.n.a.logy elsewhere in nature? Those who uphold the theory most strongly are wont to compare the development of organisms to crystal-formation in order in some way to tack on the living to the not-living. Crystal-formation, with its processes of movement and form-development, is, they say, a kind of connecting link between the living and the not-living. And in truth we find here, as in the realm of life, species-formation, development into individuals, stages and systems.

But all this takes place without any hint of ”struggle for existence,” of laboriously ”selective” processes, or of ingenious acc.u.mulation of ”variations.” The ”species” of crystals are formed not according to utility, but according to inherent, determining laws of development, to which the diversity of their individual appearances is due. If ”Life” were only a higher potential of what is already stirring in crystallisation, as this view suggests, then we should expect to find fixed tendencies, determined from within, in accordance with which life would pa.s.s through the cycle of its forms and possibilities, and rise spontaneously through gradual stages.

CHAPTER VII. CRITICS OF DARWINISM.

Let us turn now to the other side. What is opposed to Darwinism in the biological investigations of the experts of to-day is in part simple criticism of the Darwinian position as a whole or in some of its details, and in part constructive individual theories and interpretations of the evolution of organisms.

A. Fleischmann's book, ”Die Darwinsche Theorie,”(39) is professedly only critical. He suggests no theory of his own as to the evolution of life in contrast to Darwin's; for, as we have already seen in connection with his earlier book, ”Die Deszendenztheorie,” he denies evolution altogether. His agnostic position is maintained, if possible, more resolutely than before.

Natural science, according to him, must keep to facts. Drawing conclusions and spinning theories is inexact, and distracts from objective study. The Darwinian theory of selection seems to him a particularly good example of this, for it is built up _a priori_ on theories and hypotheses, it stands apart from experimentation, and it twists facts forcibly to its own ends.

It has, however, to be acknowledged that Fleischmann's book is without any ”apologetic” intentions. It holds equally aloof from teleology. To seek for purposes and aims in nature he holds to be outside the business of science, as Kant's ”Critique of Judgment” suffices to show. After having been more than a decade under the charm of the theory of selection, Fleischmann knows its fascination well, but he now regards it as so erroneous that no one who wishes to do serious work should concern himself about it at all. Point by point he follows all the details of Darwin's work, and seeks to a.n.a.lyse the separate views and theories which go to make up Darwinism as a whole. Darwin's main example of the evolution of the modern races of pigeons from one ancestral form, _Columba livia_, is, according to Fleischmann, not only unproved but unprovable.(40) For this itself is not a unified type. The process of ”unconscious selection” by man is obscure, and it is not demonstrable, especially in regard to pigeon-breeding. It is a hazy idea which cannot be transferred to the realm of nature. The Malthusian a.s.sumption of the necessity of the struggle for existence is erroneous. Malthus was wrong in his law of population as applied to human life, and Darwin was still more mistaken when he transferred it to the organic world in general. It was mere theory. Statistics should have been collected, and observations instead of theories should have been sought for. The alleged superabundance of organisms is not a fact. The marvellously intertwined conditions in the economy of nature make the proportion of supply and demand relatively constant. And even when there is actual struggle for existence, advantages of situation,(41) which are quite indifferent as far as selection is concerned, are much more decisive than any variational differences. The theory does not explain the first origin of new characters, which can only become advantageous when they have attained to a certain degree of development. As to the ill.u.s.trations of the influence of selection given by Darwin, from the much discussed fict.i.tious cases, in which the fleet stags select the lithe wolf, to the marvellous mutual adaptations of insects and flowers, Fleischmann objects that there is not even theoretical justification for any one of them. The spade-like foot of the mole is not ”more useful” than the form of foot which probably preceded it (_cf._ Goette), it is merely ”different.” For when the mole took to burrowing in the earth and adapting itself to that mode of life, it _ipso facto_ forfeited all the advantages of living above ground. The postulated myriads of less well-adapted forms of life are no more to be found to-day than they are in the fauna and flora of palaeontological times. The famous giraffe story has already been disposed of by Mivart's objections. As to the whales, it is objected that the earliest stages of their whalebone and their exaggerated nakedness can have been of no use, and a series of other alleged selective effects of ”utility” are critically a.n.a.lysed. The refutation of the most brilliant chapter in the Darwinian theory, that on protective coloration and mimicry, is very insufficient. A long concluding chapter sums up the fundamental defects of the Darwinian theory.

For the most part, Fleischmann simply brings forward objections which have been urged against the theory of selection from the first, either by naturalists or from other quarters. The chief and the most fatal of these which are still current are the following: The theory of selection does not explain the actually existing discontinuity of species. The real characteristics which distinguish species from species are in innumerable cases quite indifferent from the point of view of ”utility” (Nageli, Bateson). ”Selection preserves the good and weeds out the bad.” But where does the good come from? (De Vries). The first beginnings of what may later be useful are almost always useless. The theory of selection might perhaps explain the useful qualities, but not the superfluous, useless, or directly injurious characters which actually exist. Confirmation of the theory of descent may be found in the palaeontological record, but it affords none of the theory of selection. Natural selection is continually being neutralised by subsequent inter-crossing and reversion. Natural selection may indeed prevent degeneration within the limits of the species by weeding out what is weak and bad, but it is powerless beyond these limits, and so forth.(42)

These ever-repeated and ever-increasing objections are purely critical. As this is true of Fleischmann's whole book, it is therefore unsatisfactory.

It leaves everything in the mist, and puts nothing in place of what it attempts to demolish. But attempts are being made in other quarters, especially among the Lamarckians, to build up an opposition theory.

Lamarckism and Neo-Lamarckism.

The ”Lamarckian” view as opposed to the Darwinian continues to hold its own, and indeed is more ardently supported than ever. On this view, evolution has been accomplished not by a laborious selection of the best which chanced to present itself-a selection in relation to which organisms remained pa.s.sive, but rather through the exertions of the organisms themselves. It has been especially through the use and exercise of the various organs in response to the requirements of life, through the increased exercise of physical and mental functions, that the organism has adapted itself more diversely and more fully to the conditions of its life. What one generation acquired in differentiation of structure, in capacities and habits, through its own exertions, it handed on to the next. By c.u.mulative inheritance there ultimately arose the fixed specific characters, and the diversity and progressive gradations of organisms have gone hand in hand with an ever increasing activity. And as with the physical so it has been with the mental. Through continual use and exercise of the functions their capacity has been increased and modified.

Through the frequent repet.i.tion of voluntary actions necessary to life the habitual use of them has come about. Habits that have become fixed are correlated with habitual psychical predispositions. These, gradually handed on by inheritance to the descendants, have resulted in the marvellous instincts of animals. Instinct is inherited habit that has become fixed. Corresponding to this there is on the other hand the recognition-in theory at least-that the disuse of an organ, the non-exercising of a function leads to degeneration of structure and so co-operates in bringing about a gradual but persistent modification of the features and const.i.tution of organisms.

These views, which have grown out of Lamarck's fundamental ideas (”Philosophie zoologique,” 1809) are now usually a.s.sociated with the theory advanced chiefly by Etienne Geoffrey St. Hilaire (”Philosophie zoologique,” 1830), the opponent of Cuvier, and the ally of Goethe, of the direct influence of the _monde ambiant_. The ”surrounding world,” the influences of climate, of locality, of the weather, of nutrition, of temperature, of the salinity of the water, of the moisture in the air, and all other conditions of existence, influence the living organism. And they do so not indirectly, as is implied in the process of selection, simply playing the part of a sieve, and not themselves moulding and transforming, but _directly_ by necessitating the production of new developments in the living substance, new chemical and physiological activities, new groupings and changes of form, and new organs.

Darwin himself did not regard these two theories as opposed to the theory of selection, but utilised them as subsidiary interpretations. It is obvious, however, that at bottom they conceal an essentially different fundamental idea, which, if followed out to its logical consequences, reduces the ”struggle for existence” to at most a wholly indifferent accessory circ.u.mstance. Weismann felt this, and hence his entirely consistent endeavours to show by great examples, such as the origin of flowers, the mutual adaptations of flowers and insects, the phenomena of mimicry, and many other cases, that neither the Lamarckian nor any other factor in evolution, except only natural, pa.s.sive selection, suffices as an interpretation. From the Darwinian standpoint he is absolutely right, and must needs speak of the ”omnipotence of natural selection,” for it must either be omnipotent, or it must give place to the other two factors, and retain only the significance we attributed to it in another connection (p. 157), which amounts to saying none at all. It is obvious enough why the discussion as to these factors should centre round the question of the ”inheritance of acquired characters,” ”acquired” either through the use or disuse of organs, the exercise or non-exercise of functions, or through the stimuli of the external world.

The neo-Lamarckian conflict with Darwinism has become more and more acute in recent times, and the neo-Lamarckians have sometimes pa.s.sed from contrasting rival interpretations to excluding the Darwinian factor altogether. As the particular champion of the neo-Lamarckian view, we must name Th. Eimer, the recently deceased Tubingen zoologist. His chief work is in three volumes, ent.i.tled ”Die Entstehung der Arten auf Grund von Vererbung erworbener Eigenschaften, nach Gesetzen organischen Wachsens.”(43) It is a polemic against Weismannism in all details, even to the theory of ”germinal selection.” Eimer follows in the footsteps of St.

Hilaire, and shows what a relatively plastic and sensitive creature the organism is to the surrounding world, the conditions of nutrition and other such influences. There is in this connection a particularly instructive chapter on the physiological and other variations brought about by external influences which act as ”stimuli of the nervous system.”

The whole theory of Lamarck and St. Hilaire transcends-notwithstanding the protests of Eimer to the contrary-the categories of the mechanical theory of life, and this chapter does so in particular. The array of facts here marshalled as to the spontaneous self-adaptation of organisms to their environment-in relation to colour mainly-forms the most thoroughgoing refutation of Darwinism that it is possible to imagine. It is shown, too, by a wealth of examples from osteology, how use (and the necessities of the case-a consideration which again goes beyond the bounds of mere Lamarckism) may modify, increase or diminish vertebrae, ribs, skull and limbs, in short, the whole skeleton.

Ka.s.sowitz is equally keen and convinced in his opposition to natural selection, and in his comprehensive ”Allgemeine Biologic”(44) he attacks orthodox Darwinism from the neo-Lamarckian standpoint. The whole of the first volume is almost chapter for chapter a critical a.n.a.lysis, and the polemical element rather outweighs his positive personal contribution. He criticises very severely all attempts to carry the Darwinian principle of explaining adaptations into internal and minute details, arguing against Roux's ”Struggle of Parts” and Weismann's ”Germinal Selection.” And though he himself maintains very decidedly that the ultimate aim of biology is to find a mechanical solution of the problem of life, he criticises the modern hypotheses in this direction without prejudice, and declares them unsuccessful and insufficient, inclining himself towards the ”neo-vitalistic reaction” in its most recent expression. Along with Eimer and Ka.s.sowitz, we may name W. Haacke, especially in relation to his views on the acquisition and transmission of functional modifications and his thoroughgoing denial of Darwinism proper. But his work must be dealt with later in a different connection.(45)

These neo-Lamarckian views give us a picture of the evolution of the world that is much more convincing than the strictly Darwinian one. Instead of pa.s.sive and essentially unintelligent ”adaptation” through the sieve of selection, we have here direct self-adaptation of organisms to the conditions of their existence, through their own continual restless activity and exertion, an ascent of their own accord to ever greater heights and perfections. A theory of this kind might easily form part of a religious conception of the world. We might think of the world with primitive tendencies and capacities, in which the potentialities of its evolution were implied, and so ordered that it had to struggle by its own exertions to achieve the full realisation of its possibilities, to attain to ever higher-up to the highest-forms of Being. The process of nature would thus be the direct antic.i.p.ation of what occurs in the history of man and of mind. And the task set to the freedom of individual men, and to mankind as a whole, namely, to work out their own nature through their own labour and exertion, and to ascend to perfection-this deepest meaning of all individual and collective existence-would have its exact prelude and preparation in the general nature and evolution of all living creatures.

The transition from these theories of nature to a teleological outlook from the highest and most human point of view is so obvious as to be almost unavoidable. And although a natural science which keeps to its own business and within its own boundaries has certainly no right to make this transition for itself, it has still less right to prevent its being made outside of its limits.

Theory of Definite Variation.

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