Philosophy of the Unconscious

by Eduard Von Hartmann

  But now I ask, which conception is the more monstrous, this, that an individual of a higher species is evolved from the ovum of a lower species, or this, that the ovum of the higher species was made at a stroke by spontaneous generation, an ovum, indeed, from which absolutely nothing but this higher species could proceed, and in which consequently all the characters of the higher species were already implicitly contained? It is, moreover, to be remarked that the ova of the highest and those of the lowest animals are morphologically and chemically so similar, and the first stages of development—of embryonic development—are so uniform, that they are not at all or scarcely, and even then for the most part only by accidental signs, to be distinguished. It is of no avail to rely on this, that usually all the characters of the genus are actually implicitly contained in the fertilised ovum of a species. However correct this (for the rest indemonstrable) view may be, yet an ovum must always have already passed through a number of stages of development before it can possess independent existence, and the young be hatched by the action of solar heat, or the animal heat of the foster parents, or the temperature of the earth for the time being, not to mention that the ova of the animals which bring forth living young never attain this independence. Where now shall this development of the ovum before self-dependence have taken place; whence is it supposed to have got its stock of albumen, unless from a female animal; whence came the first focus for the primitive yolk-sac, unless it lay in an ovary? Albumen is in truth not so common in inorganic nature that the spontaneous generation of a yolk-sac were something easy. At all events, it would have cost the Unconscious infinitely more difficulty to produce by spontaneous generation such an egg, possessed of all the characters of the higher species to be newly created, than either to evolve an individual of the new higher species from an ovum containing the characters of another inferior kind, by obliterating these characters always merely foreshadowed in the germ, and adding new ones, or however to develop the ovum containing entire the characters of the new higher species in the ovary of an individual of a lower species, or, lastly, to make use of both expedients at the same time, i.e., to develop an ovum particularly favourably constituted in view of the new species, both in the ovary of the inferior individual, as well as after quitting the same with the modifications necessary for attaining the higher species. Where is the natural origin of the individual unless in the ovum? Where is the natural origin of the ovum unless in the ovary of a female animal? How inconsiderable appear the difficulties, which the Unconscious has to overcome in the evolution of a higher organism from the womb of a lower, to the colossal difficulties which would oppose it in the original creation of the higher organism. When we have thus only a choice between these two assumptions, we shall unhesitatingly decide for the former, that the higher species proceeds by reproduction from the lower, but by a reproduction with modified development of the ovum, as Kölliker (Siebold and Kölliker, Zeitschrift für wissenschaftl. Zoolog. and Medic., 1865, Heft 3), who adopts this point of view, calls it, “heterogeneous generation.”

  We have hereby gained a fixed support for the intermediate stages presupposed from the very first for the production of higher animals; it is a scale of ever higher and higher species by which the organising Unconscious realises the highest organisms. Certain, however, as is this general result, no less certain, however, is it that we cannot stop there.

  Although we have proved in Sect. A. Chap. viii. that the Unconscious is active at every moment of organic formation at every part of the organism, and makes its influence felt quite specially in the relatively impetuous embryonic development, yet, on the other hand, it is not to be denied that, as everywhere where it is possible, so also for the evolution of the ovum the Unconscious has, as far as possible, facilitated its intervention and reduced the material actions to a minimum by previously established mechanisms. Accordingly, in all probability, there exists in the male and female reproductive materials an energy intentionally implanted by it itself at earlier stages, which enables these substances to develop under the requisite psychical guidance more easily in the direction predesignated in the parental organism than in any other. Now since the Unconscious always follows the line of development previously indicated, as the direction corresponding in general to its predetermined ends, and offering the least resistance to realisation, if it has no particular reason for deviation for a particular purpose; and since such a reason is wanting in ordinary generation, where the sole end is the preservation of the species, it usually takes, in the psychical guidance of embryonic development, the course indicated as the easiest by the qualities previously imparted by itself to the materials of generation, i.e., the begotten resembles the begetters, and this phenomenon is called the “transmission or inheritance of qualities.”

  From such a universal teleological rule the Unconscious is the less inclined to deviate the more general is its scope, e.g., from the inorganic laws of Nature not at all. Since now the difficulties are already sufficiently great, which arise through the transcending of old species and the adding on of new characters, the Unconscious will seek to withdraw itself as far as possible from those difficulties, which it would have to overcome in the annihilation of such characters of the old species as could or should not be taken over into the new species, and will for this purpose seek to create the new higher species from those species in which only new characters are to be added, but the fewest possible or no extant positive characters are to be destroyed, i.e., from relatively imperfect species, provided with few specific characters, affording much scope for further development, but not from species already highly developed, strongly differentiated, and endowed with many and definite characters.

  This is fully confirmed by the palæontological history of the animal kingdom. Every important order of the animal kingdom resembles the branch of a huge tree, and at a particular geological period is developed from lowly beginnings into higher forms. It is not these latter, however, that resemble the extremities of the branch, whence, under the changed circumstances of a later geological period, a new animal order arises,—for they have by abundance of decided characters strayed, as it were, into a cul de sac,—but those imperfect primitive stocks of the order, that have maintained themselves in the struggle for existence with trouble and difficulty all through the earlier period against their far superior descendants, the shy offshoots of the branch, as it were, standing nearest to the trunk, from which, by addition of new and hitherto non-existing characters, the new order subsequently arises. This is a general law of Nature, the special application of which to the development of humanity has long been familiar to every student of history. If the races or stocks, which at a certain time represent the summit of the human evolution, have fallen into stagnation (or temporary depravity), there appear less developed virgin races or stocks, as it were on the theatre of history, to develop speedily to a height which decidedly exceeds the bloom of the previous most advanced races (pp. 11–13). It is the same in the development of the animal kingdom, only that the advance in organisation always going hand in hand with growing intelligence is there more obvious than in the case of man, who, with the exception of the increased development of brain, forms and fashions the organs of his growing culture into external instruments (instead of like the animal into bodily organs).—Defective as is our knowledge of the transitional stages, derived from the forms preserved in the existing fauna and the palæontological remains hitherto found, it yet perfectly suffices to sustain the above assertion.

  After the Crustacea have attained their maximum development in the crabs, the Arachnida make their appearance with the very imperfect mites; after these have reached their limits in the spider, there follows in the insects a retrogression to the inferior lice. The highest forms of the Mollusca are the Sepiæ, of the Articulata the Hymenoptera; both are far more highly organised than the lowest known fishes, both possessed a form as perfect as that met with to-day, before the Vertebrata existed at all. But they were too one-sidedly and t
oo completely differentiated for a class to spring from them requiring quite other fundamental structural conditions. Fishes rather developed from Ascidians, Worms, and Crustaceans. For reasons easy to understand, the oldest fossil fishes belong only to the transitional forms of the Crustacea, because the other two classes were too soft to leave fossil remains; on the other hand, the transitional forms of the latter have remained as two species down to the present day. The almost transparent little lancelot, two inches long, living on the coasts of the North Sea and Mediterranean, Amphioxus lanceolatus Pall, possesses no skull and no vertebral column, but only a simple massive cartilaginous cord as support of the nervous axis, no brain separated from the spinal cord, no heart no spleen, only a cœcum in lieu of a liver, no coloured blood, no proper fins, but merely a narrow membranous border expanded at the caudal extremity. Just as Linnæus had regarded another fish (Myxine) as a worm, so had Pallas taken the Amphioxus for a slug (Limax); but recent anatomical investigations have proved that it is constructed on the type of the Vertebrata, represents the lowest known stage of fishes, and altogether must pass for the prototype or primitive form of the, whole vertebrate kingdom, as the immediate descendant of the oldest Vertebrata of the primæval world, whose relatives undoubtedly peopled the primitive seas in innumerable quantities. The Amphioxus is most related to the Ascidians (a kind of mollusc), in which not only in embryonic development1 (as in certain lower worms) the peculiar formation of the so-called germinal membrane, hitherto regarded as characteristic of the vertebrate type, presents a similar appearance to that of Amphioxus, but which even at a certain stage of their development possess the cartilaginous groundwork of the vertebral column, although, to be sure, they afterwards lose it again.

  Passing from the fishes to the Amphibia, a transition is again presented only in imperfect and lowly forms, whilst the two classes part company from one another the more they are developed in their characteristic one-sidedness. The scaly salamander living in the Amazon, or Lepidosiren paradoxa Natt., is an animal three feet long with a fishlike form, with gills and a scaly covering, which altogether answers to that of the osseous fishes. Two fins on the head and two on the belly indicate the anterior and posterior limbs. Besides the gills, however, the animal has also a pair of lungs, which open by an air-passage into the œsophagus; accordingly an organisation such as never occurs in the true fishes, but, indeed, in the fish-like Saurians, e.g., Proteus. Respiration and circulation accordingly assign the scaly salamander to the higher class of the Amphibia, whereas all the rest of the organisation is that of a fish. If we now consider the stage of development of the animal simply as vertebrate, it stands as low in the scale as possible. Its skeleton is only imperfectly ossified, the vertebral column consists of an undivided cartilaginous cord, to which the ossified vertebral arches are fitted. Similar to Lepidosiren is constructed the Protopterus living in Western Africa, which in the flooded marshes only needs gills, in the dried-up marshes, however, lungs. Huxley, fifteen years ago, found these marks sufficient to fix the derivation of the double-breathing scaly salamander from the circular-scaled cartilaginous fishes, a determination no longer doubtful since the discovery of an animal (Ceratodus) by Krefft in the river Burnett (Queensland), which is exactly intermediate between the cartilaginous fishes and scaly salamanders (figured and described in the “Ergänzungsbl.,” vi. p. 227). It may accordingly be regarded as proved that the Amphibia (and along with these also the higher animals) spring from the cartilaginous fishes, and that the osseous fishes now mostly peopling the waters form a side-branch in the pedigree of the animal kingdom, in which they rank decidedly higher than the cartilaginous fishes.—These examples may suffice to verify and to illustrate our assertion.

  These facts, which Darwin admits, cannot be explained by his assertion that the strict constancy of the transmission of qualities is in every case determined by the duration of their persistency, and that every species is the less inclined to deviate from its specific character the older it is. There lies in this assertion the truth that young species stand nearer to the original stock than older ones, which, unmindful of their origin, as it were, have become arrested in their limited idiosyncrasies, and that therefore young species of common descent show, even among one another, more affinity and capability of mixture than older ones. Such young species which give rise in crossing to hybrid races, are called fluent species, in contrast to the self-contained fixed species, in which each hybrid race again speedily perishes by reversion to the stock. Such fluent species are, e.g., the species of dogs, finches, mice, whilst the races of man are in the stage of transition from fluid to fixed species; at that stage, indeed, when between the more remote forms of the series no permanent hybrid race is any longer to be obtained.—Decidedly incorrect, on the contrary, is the above assertion of Darwin, so far as he asserts that universally and uniformly the capability of varying decreases with the length of persistence; rather the artificial breeding of plants and animals has hitherto revealed no difference in the capacity for variation of old and young species. But suppose the assertion were correct, we should in consequence expect just the contrary of what it is said to explain; for as the more perfect and highly differentiated species are always of more recent existence, accordingly are younger than their less perfect stem forms, the latter, as the older, would be less adapted for commencing a new-development series, whereas the facts teach the contrary. We must therefore maintain that more perfect species do in fact vary just as easily and just as much as the more imperfect, if they are caused so to do by change of circumstances; only the former have not the tendency to be so easily converted into higher orders as the latter; and why this is not the case, and why this conversion into a new order only takes place when within the previous order the abundance of the more perfect forms is exhausted, can never be proved from the assumptions of the Darwinian theory—

  Having become acquainted in heterogeneous generation with the one expedient employed by the Unconscious to facilitate the formation of new species, let us observe its operation a little more closely. Hitherto we have not at all taken into consideration how far in heterogeneous generation the offspring may differ from the parents. It is, however, clear that the Unconscious, in the formation of higher species, will make no unnecessary leaps, but draw the boundaries as close as possible to one another. A leap there certainly always is, for otherwise indefinitely numerous generations must fill up the gap between one species and the next, which in the limited period of development of organisation on the earth is impossible. But at any rate, the actual step will overleap no species lying directly in the line of development, but at the most pass at once to the next higher species.

  Here we approach the question how far a species may lie from the nearest related one, or how the notion of a species may exclude, on the one hand, differences that are greater than specific, on the other hand, those that are less than specific; or, in a word, the question with regard to the definition of the term Species. But now, every unprejudiced naturalist admits that such limitations of the idea of species are not at all found in Nature, but that it passes by very fine degrees on the one side into the notion of the variety or of the race, and on the other hand into that of the family, or however one calls the nearest higher class; that accordingly, as in all quantitatively limited notions, it is a matter of subjective caprice and of mutual agreement how far one shall extend the notion of species; that, indeed, on the whole there is agreement as to those anatomical and outward marks which appertain to a difference of species, but that naturally at the boundaries differences of opinion will always remain as to the application of this notion. Some have thought to settle the dispute by setting up as a criterion of the specific difference of two animals the impossibility of begetting fertile offspring. But, in the first place, two animals are not necessarily very different because they can beget no fertile offspring, but they are unable to engender fertile offspring because they exceed a certain limit of difference, and this mark would accordingly not
concern the essential notion, but only a corollary of the specific difference. Secondly, however, the limit of the generation of fertile offspring is just as fluent as the idea of a species, since only the relative number of procreative acts giving rise to fertile offspring becomes less, the more diverse are the animals; but no one can assert before the trial of infinitely numerous experiments that a procreation of fertile offspring is impossible between these two animals. Thirdly and lastly, this mark is, in fact, in not a few cases, in contradiction with the established use of the idea of species, for from animals universally recognised as specifically distinct fertile offspring have been obtained by crossing, e.g., from horse and ass (in Spain), from sheep and goat, from goldfinch and siskin, from Mathiola maderensis and incana, from Calceolaria plantaginea and integrifolia, and many more; nay, even voluntary crossings, without the intervention of man, have been found to take place between wild or half-wild animals (between dog and she-wolf, fox and bitch, steinboc and goat, dog and jackal, &c.); and there are numerous mongrel breeds which yield fertile offspring indefinitely, e.g., hybrids of hare and rabbit, of wolf and dog, goat and sheep, camel and dromedary, lama and alpaca, vicuna and alpaca, steinboc and goat, &c. On the other hand, the state of the case varies much with races. Some can, others will not at all intermingle; with others, again, fertility is actually very much limited in the course of generations. As little as the fertility of hybrids for species in general, so little can the incapability of yielding persistent hybrid races with other species be regarded as an absolute mark of fixity of species (in contrast to fluent). This contrast, too, is only to be limited quantitatively; for, in the first place, the question always is with which other species the hybridism is attempted; and, secondly, even in the now most fixed species, sometimes, if very rarely, surprising reversions to an ancestral form make their appearance (atavism).