Ernst Haeckel

“ No great and general question in zoology and botany, in anatomy and physiology, can be discussed and solved without the question of origins, "the genesis of the generated," presenting itself before everything else. ”

“ Spencer belongs to those older nature philosophers who already before Darwin recognized in the monistic theory of evolution the magic key which would unlock the riddle of the world. He belongs also to those evolutionists who justly lay the greatest stress upon progressive inheritance, upon the "transmission of acquired characters." Like myself, Spencer has, from the beginning, fought in the most resolute manner the germ-plasm theory of Weismann, which denies the most important factor in the theory of descent and wishes to explain the same chiefly through the omnipotence of natural selection. ”

“ Not only in his pentadactylate hands and feet, but also in other anatomical features does man show the characteristic inherited features of his stock more clearly than many other mammals, as, for example, ungulates, cetaceans, and bats.
The immeasurable significance which this secure knowledge of the primate origin of man possesses for the entire range of human science lies clear before the eyes of every unprejudiced and logical thinker. ”

“ The science which to-day in most textbooks and from most academic chairs is taught as "psychology" is not a true empirical science of the mind, not the physiology of the mental organs, but rather a fantastic metaphysics, compounded of one-sided introspective observation of self and of uncritical comparisons, of mis- understood data and incomplete experiments, of speculative errors and religious dogmas. ”

“ Not less important than these morphological considerations are the physiological ones that are taught us by that instructive but hitherto, alas! too much neglected science, comparative physiology. For an unprejudiced comparison of all the activities of life teaches us that in this department also there is nowhere any radical distinction between man and apes. Our entire nutrition, secretion and circulation, breathing and digestion, are performed by the same physical and chemical processes as with the anthropoid apes. ”

“ Much more difficult and dark is the oldest history of our stock, the derivation of a vertebrate stem from an invertebrate ancestry. As none of these possessed any hard and petrifiable parts of the skeleton (resembling in this respect the lowest vertebrates, the cyclostomata and acrania) the evidence of paleontology entirely fails us here; we must rely alone upon the other two records of our family history, upon comparative anatomy and ontogeny. ”

“ The deep significance of this information will be clearer to us when we consider the extraordinary differences in mental capacity that exist within the human species itself. There we see, high above, a Goethe and a Shakespeare, a Darwin and a Lamarck, a Spinoza and an Aristotle, and then, far below, a Veddah and an Akkah, a Bushman and a Patagonian. The enormous difference in mental capacity between these highest and lowest representatives of the human race is much greater than between the latter and the anthropoid apes. ”

“ With the greatest obstinacy he has maintained the doctrine of the constancy of species, which is now abandoned by all naturalists of good judgment; but in what now consists the essential idea of a "true species" he can no more tell than any other opponent of evolution. The most important conclusion from the latter, the "descent of man from the ape," Virchow is well known to attack with zeal and energy. "It is quite certain that man did not descend from the apes." ”

“ Linnæus himself had already, in 1735, in his fundamental "Systema Naturæ," placed man at the head of the mammals, grouping him with the apes and the lemurs in the "Anthropomorpha," or man-like creatures; later he called these dominant animals, or "Primates," the "lords of creation."
Man possesses in his bodily structure all the marks by which mammals are separated from other vertebrates, and there has, therefore, never been any controversy about his belonging to this class. ”

“ Our mental ability results from the same physical and chemical laws as does that of the apes. The mechanics of our bony frame and the movements our muscles impart to this arrangement of levers are in no way different in man and the anthropoid apes. It was formerly thought that walking erect was a special attribute of man. We now know that this can sometimes be done by the gorilla and the chimpanzee, and especially by the gibbon. ”

“ All reliable recent researches have here unanimously confirmed the proposition which Lamarck, Darwin, and Huxley declared to be the most important result of the theory of evolution—the proposition that the immediate placental ancestors of man were a series of tertiary primates, and the next nearest were the anthropoid apes, the anthropomorphous catarrhines. ”

“ For all other problems which the human mind can investigate and understand are conditioned chiefly by the psychological theory of perception, and this again depends upon the animal nature of man, upon his origin, his development, and his mental powers. ”

“ The various sounds by which apes express their sensations and their wishes, their affection, and aversion must by comparative physiology be considered as speech, just as much as are the similarly imperfect sounds that children make when learning to talk, and as the manifold tones by means of which social mammals and birds impart to each other their ideas. The modulated song of the singing bird belongs to speech just as much as the similar song of man. Besides, there exists a musical anthropoid. ”

“ No one among the philosophers has more thoroughly based his authoritative influence upon a contemplation of the entire universe than has the great English thinker Herbert Spencer, one of the few learned men of the present day who unites the most profound scientific training with the deepest philosophical speculation. ”

“ The historical succession of the principal steps in the vertebrate stock is thereby definitely established, and this success is much more important for an understanding of the human family tree than if we had succeeded in placing, in a hundred fossil skeletons of lemurs and apes, the entire series of our Tertiary primate ancestors in coherent succession before our eyes. ”

“ For the natural system is, within the order of the primates, an expression of genealogical relationship, just as it is in every other group of the animal and vegetable kingdoms. Hence result the following important inferences as to the genealogical tree of man: (1) The primates form a natural monophyletic group; all "dominant animals," lemurs, apes, and man himself sprang from a common original stem form, a hypothetical Archiprimas. ”

“ As man has in the rest of his bodily structure the morphological characters of the Old-World apes and is, like them, thus distinguished from the apes of the New World, certain zoologists have assigned to him a situation within the former group. ”

“ I shall to-day, before this zoological congress, speak only of the last-named service of Darwin, and do this for the especial purpose of showing critically the certainty to which we have attained in our present knowledge of the origin of man and of the various branches of his genealogical tree. ”

“ Secondly, comparative ontogeny teaches us that the very highly complex brain of man has developed out of the same rudimentary form as that of all other vertebrate animals—out of five cerebral vesicles of the embryo that lie one behind the other. ”

“ Since, in spite of this, we find that the soul of man is to-day regarded in the widest circles as an especial, "being" and as the most important witness against the decried doctrine of the descent of man from apes, we explain it on the one hand by the wretched condition of the so-called "psychology," on the other by the widespread superstition concerning the immortality of the soul. ”

“ For the adaptation of the new-born mammal to suckling involved a series of changes not only in its own body but in that of its mother. While in the skin of the mother the mammary glands developed through the irritation and differentiation of a group of ordinary skin glands, there was formed in the mouth of the child, by the act of sucking, the soft palate and afterwards the epiglottis—two organs of the throat that occur only in mammals. ”

“ Whatever system of organs be studied, the comparison of their modifications in the ape series leads us to one and the same result—that the structural differences which separate man from the gorilla and the chimpanzee are not so great as those which separate the gorilla from the lower apes. ”

“ Most of the so-called psychologists know nothing at all of the brain and organs of special sense, that wonderful and incomparably complex apparatus which solely and alone is the organ of the mental faculties in man and in animals. ”

“ We only need to compare carefully the skeleton of the four legs of our salamanders and frogs with the bony framework of our own four limbs to convince ourselves that with these amphibians the same characteristic and peculiar structure had arisen as they handed down by inheritance to all the sauropsida and mammalia ”

“ Every great osteological collection contains similar specimens; experienced hunters know that fractures and inflammations of bones in foxes, hares, harts, roebucks, etc., are often healed quite well, without the intervention of man, while those animals are in a state of freedom. Finally, Virchow asserted that the deep notch between the orbital edge and the low skullcap of Pithecanthropus—a sign of a very deep conformation of the temporal fossa—were decisive for the ape-like character of the skull, and that such a formation never occurs in man. ”

“ It is well known that in the course of the forty years which have passed since the first publication of Darwin's theory an extensive polemical literature has appeared, relating to both its general significance and to the evolution of man, its most important result. ”

“ His contention that the skull and the femur of Pithecanthropus could not have belonged together, that the first belonged to an ape and the second to a man, was rejected at once by the expert paleontologists present, who declared unanimously that, in view of the extremely careful and conscientious account of the discovery "there could not the slightest doubt exist that the remains belonged to one and the same individual." ”

“ The gibbons more than the other anthropoids have the habit of voluntarily assuming the upright position, whereby they walk upon the entire sole of the foot and use their long arms as balancing poles. The other modern apes (orang, chimpanzee, and gorilla) seek the upright position, and when they use it do not tread upon the entire sole but upon the outer edge of the foot ”

“ Man, like the Old-World apes, possesses thirty-two teeth of very characteristic structure and arrangement. The New-World apes have, on the contrary, thirty-six teeth, namely, one more premolar in each half Of either jaw. ”

“ I dwelt especially, however, upon the logical connection between the evolution of man and the theory of modification by descent; if the latter is true it gives absolute validity to the former^ "The proposition that man has developed from the lower vertebrates and, indeed, immediately from the true apes is a special deduction which must necessarily result from the general induction made by the law of the theory of descent." ”

“ This in turn is derived from an older, generalized ape form which lived in the older Miocene period, and which maybe regarded as the common ancestor of the Old World apes, both the tailed Cynopitheci and the tailless Anthropomorpha. Among the latter we now recognize the two living species of the gibbon which stand very near to Pliopithecus, as well as fossil anthropoid apes that lead directly to Pithecanthropus. Such an intermediate stem form is Pliopithecus sivalensis, whose skeleton was found in the early Tertiary layers of eastern India in the Pliocene Siwalik strata. ”

“ That the latter is indissolubly connected with the former is now generally recognized, and it is exactly this intimate connection that explains the stubborn resistance that has been shown to the entire theory of evolution by all mystical and orthodox schools, by all men who have not been able to free themselves from the traditional anthropocentric superstition. In the sharp fight that has ensued on this subject the most varied weapons have been used. ”

“ They remain at a very low stage of development and are allied to the older platyrrhines and prosimians. On the other hand, the tailless apes (Anthropomorpha) rise to a height of organization that makes clear as day the immediate transition to the human form. For that reason one of the most profound students of the anatomy of primates, Robert Hartmann, went so far as to separate the entire order of primates into three families: (1) Primarii (man and the anthropoid apes) ; (2) Simiæ, or apes proper (catarrhines and platyrrhines) ; (3) Prosimiæ (lemurs) . ”

“ Here lies the physiological source of that highest form of maternal love which has exercised such a significant influence upon the family life of various mammals, as well as upon the culture and higher mental life of man. ”