Part 8

Every human individual commences his term of separate existence as a tiny speck of protoplasm, and slowly advances through the phases of separate cell-life, multicellular existence, and the gastrula, vermiform, and pisciform stages, being finally born as a partially-developed member of the human family, from which moment he grows rapidly to the perfection of the adult state, having accomplished, in the short period of about a score of years, precisely what his counterpart, the race, effected in many millions of years. During the period in which the individual dwells _in utero_ great and rapid modifications take place in the general construction of the fœtus; sensory perception makes its appearance very early, being followed quickly by the first attempt at differentiation of special sense-organs in the form of tiny surface depressions; the brain and spinal system gradually take shape and make ready for future action; and the little body slowly assumes a form suitable for separate extra-uterine existence. At the moment of birth the brain and special sense-organs are not yet developed to such a degree that they can properly discharge the functions they are called upon to perform in the mature state; they have to advance gradually to perfection in harmony with the growth of the whole body; and thus it is that a newly-born individual does not see, hear, or exhibit signs of consciousness until some time has elapsed from birth, although it is, at first, quite sensitive to cold and heat. If a lighted candle be held in front of the eyes of a newly-born infant, and moved to and fro, it will be at once observed that the child is totally unconscious of it; and, if a gun be fired off in the room occupied by the child, the effect upon the infantile organism is _nil_; but, if the air of the room be allowed to cool, the effect will be at once perceived, for the muscles of the child will soon begin to contract, and his vocal bellows to act vigorously. Gradually, however, the sight, hearing, etc., become adjusted, and the infant begins to take notice of surrounding objects, until at about a month after birth pain and pleasure, the first indications of the dawn of the mental powers, manifest themselves. Conscious, as distinguished from instinctive or non-conscious, memory appears to be exercised at about the thirteenth week, and to be immediately followed by association of ideas, the recognition of places and persons, and dreaming. At the same time that these indications of intellectual development are manifesting themselves, a corresponding unfolding of the emotions is observed. Side by side with memory appears fear, followed by pugnacity, play, and, later, anger; while, still later, about on a par with the first period of dreaming, or at about the age of five months, are manifested emulation, jealousy, joy, and grief. In about another month we notice that the child begins to understand words, while, on the emotional side, he evinces signs of awakening sympathy, curiosity, revenge, and gratitude, followed within a couple of months by pride, shame, deceitfulness, passionateness, cruelty, and ludicrousness, which show themselves at the moment the child appears to first exercise what we term true reason. From this point we see rapidly unfolded the higher products of intellectual development, the first of which is morality of a very indefinite kind, which immediately precedes articulation at the age of about fourteen months, being closely followed by knowledge of the use of various simple instruments, afterwards at the age of twenty months by concerted action, and still later by speech, which generally is effected at the age of two years, or rather earlier. Following quickly upon speech we observe judgment, recollection, and self-consciousness manifesting themselves, and, by the time the child has attained the age of two years and a half, morality of a definite kind makes its appearance.

Tracing the child’s development still further, we find the next important intellectual manifestation—viz., superstition—to take place at about three years of age, while concurrently the following emotional products appear—avarice, envy, hate, hope, vanity, mirth, and a love of the beautiful, which are followed, in the course of a few months, by awe and an appreciation of art. From this age to the condition of adult life, the intellectual faculties develop according to the surroundings of the individual, while, on the emotional side, reverence, remorse, and courtesy make their appearance at about the age of five years, and melancholy and ecstasy at about the tenth year.

In the foregoing ontogenetic mirror will be found the key to the unfolding of the great mystery of the evolution of mind in the animal kingdom. We have only to take the geological periods one after the other, and study the various life-forms found in each to see at once that, with the race, the order of sequence in the appearance of the intellectual and emotional faculties is precisely the same as with the individual. We may place the new-born infant intellectually on a par with the lowly molluscs or the vermiform little animals which existed in the Cambrian period, in which little organisms probably pain first made its entry upon the earth, followed by the appearance of pleasure, memory (conscious), and association of ideas in the lowly crustaceans of the later Cambrian and early Silurian periods. With the spiders, fishes, and crabs of the later Silurian and Devonian periods we have brought before us the faculty of recognising places of which these animals are capable, which places them intellectually on a level with a child of four or five months old.

The recognition of individuals next made its appearance in the reptiles of the Carboniferous and Permian epochs; while the birds of the Oölitic and Cretaceous periods were the first to dream, and are thus placed on an intellectual level with a child of five or six months. The emotional development coincides with the intellectual, just as in the case of the infant, for we find fear manifesting itself among the lower molluscs, pugnacity among the crustaceans, play among spiders and crabs, anger among reptiles, and emulation, jealousy, joy, and grief among birds. We now rise in the palæontological scale to the Tertiary period, and find in the Eocene age equine and other mammal forms, such as cats and pigs, which are capable of understanding words and signs, and among which we notice a manifestation of sympathy, curiosity, revenge, and gratitude. In the early Meiocene age we have monkeys, dogs, and elephants exhibiting the clearest signs of true reason, as may be observed at the present day, and at the same time manifesting such emotional signs as pride, shame, deceitfulness, passionateness, cruelty, and ludicrousness, which places them on an intellectual par with the infant of less than a year old.

In the later Meiocene age we have anthropoid apes, which may be placed on a level with one-year-old infants, and from which evolved apes of a higher order, which acquired the faculty of articulation, and, afterwards becoming more human, the knowledge of the use of simple instruments, thus reaching the intellectual level of the child of fifteen months old. As the apes became more and more human in the later Meiocene and early Pleistocene ages, they gradually acquired the faculty of acting in concert and of speech; and when, having arrived at that stage of development in which they partook more of the character of savage man than human ape, judgment, recollection, self-consciousness, and, lastly, definite morality manifested themselves, thus raising the ape-like man to the level of the child of two and a half years. In the lowest savages of to-day, as well as in the old descendants of the ape-like men, superstition developed to a large extent at the same time that the emotional unfolding proceeded in the direction of avarice, envy, hate, hope, vanity, mirth, a love of the beautiful, and afterwards art appreciation, awe, reverence, remorse, courtesy, melancholy, and ecstasy, precisely as with the child of from five to ten years of age. As the race improved, becoming in turn semi-savage, semi-civilised, civilised, and cultured, the intellectual powers, of course, developed similarly, until, at the present day, we find men possessed of the most wonderful mental grandeur, we might almost say, conceivable. But this would be saying too much, for we must not forget that, just as evolution has continued in the past from eternity, so will it continue in the future to eternity; and who can tell to what heights the human mind may soar in the future?

Lofty as is the human intellect at the present time, as compared with the mental powers of those we have left far behind in the march of evolution, it is yet very far from being able to grasp many of the great problems of the universe, such as that of existence. Perhaps at some future time, in millions of ages to come, these great questions may be answered; but at present we know they baffle the wisest men, and continually remind us of the finite and limited character of our intellectual faculties.

This comparison of the mental development of the individual with that of the whole race is extremely interesting, and provides ample material for thought. By such comparison, and by it alone, can the science of psychology ever be based on a sure and enduring foundation. It is all very well for theologians and other biased people to declare that animal intelligence has nothing in common with the reasoning powers of man; but let them honestly look at the facts as they are, thanks to the indefatigable energy and indomitable perseverance of lovers of science and truth, now presented to us. Candid observers cannot fail to notice that the difference between the intelligence of man and that of the lower animals is one only of degree, and not of kind. When we see the order of sequence being followed in the development of the individual so like that of the whole race, not only as regards the bodily structure, but also as regards the mental functions, can we help arriving at the conclusion that the one is but the epitome of the other, and that the superior intellect of man is but a higher development of the so-called instincts of the lower animals? Have we not at the present day, among members of the human family itself, various degrees of intelligence, from the almost barren brains of the lowest races of savages to the brilliant mental achievements of a Newton or a Spencer?

It is beyond doubt that the intellectual superiority of civilised man over his savage brethren is due to the greater multiplicity of his objects of thought, and it follows that savage man’s intellectual superiority over the lower animals is due to the same cause. The actions of both have the same aim—viz., the supplying of the wants of the physical nature and the gratifying of the desires aroused in the mind. It is frequently asserted that man differs from the lower animals in possessing the power of reflection; but this I hold to be an exploded argument, and at variance with all recent teaching. Dogs, elephants, and monkeys most certainly possess the faculty of reflection, and it is not difficult to find races belonging to the human family whose powers of reflection transcend hardly in the least degree those possessed by the higher apes; while the difference between the reflective capacity of the lowest savage, which is of the simplest conceivable kind, and that of the civilised European, which has developed into genius, is enormous. Then, again, it is often said that only man is emotional; but one need only have an ordinary acquaintanceship with domestic animals to at once see the absurdity of this argument, for dogs are frequently observed to laugh, to cry, to express joy and gratitude by their actions, and to betray feelings of shame and remorse; while horses and elephants have been observed to punish their cruel keepers in the most cunning manner and then to laugh at the poor fellows’ discomfiture. As to the “conscience argument,” so frequently brought forward, by religionists especially, all I have to say here is that conscience, or the knowledge of the distinction between right and wrong, is not an inherent quality of the human mind, being merely a result of the operation of the reflective faculty aided by experience, as is quite evident from the fact that the ideas of morality vary according to the age in which we live. The same may be said about the greatest of all the arguments against evolution—viz., that of language; for, just as conscience is but a product of reflection and experience, so is language also. It is a mistake to imagine that the power of speech is possessed by man alone, and that his language differs altogether from the cries and signals of the lower animals, for such is not the case. Many animals possess the faculty of speech, and human language differs from that of the lower animals only in its degree of development, and in no sense in its origin. Probably all language originated in interjection, or the “instinctive expression of the subjective impressions derived from external nature,” as Mr. Farrar puts it. And, just as the reflective powers of the race were developed and shone more brilliantly as each stage in the evolutionary march of intellect was passed, so did language pass from the simple monosyllabic cries to the complex dialects of modern civilisation; and it is worthy of notice that, at the present day, or at any rate very recently, there were races of savage men inhabiting this earth who possessed no language at all, and could not, on account of their mode of living, be placed on a higher intellectual level than the higher apes; while we have the authority of the leading philologists of the times in support of the fact that the monosyllabic cries of some of the lower human tribes are quite within the grasp of the ape’s voice.

Human beings have been discovered in wild and hitherto unexplored regions who have not the remotest idea of what we should term civilisation. They lead a wandering and useless life, sleeping at nights, not in huts, nor in caves, but squatting among the branches of tall trees, where they are placed out of the reach of savage animals. They do not appear capable of expressing their thoughts in sentences, but make use of exclamatory grunts, which serve the purposes of speech quite sufficiently for their limited requirements; and their general appearance approaches to a remarkable extent that of the higher apes, in that they are almost completely covered with hair, possess a dirty brown skin, short legs, long arms, and full abdomens, can pick up stones, sticks, etc., with their toes as well as their fingers, and show few if any signs of intellectual powers. Let any one visit the Zoological Gardens, in London, and carefully observe the apes exhibited there, and then say whether there is a vast difference between some of them and the human beings who answer to the above description. One need but visit the travelling menagerie of Messrs. Edmunds, and view their “missing link,” an excellent sample of the chimpanzee troglodyte, to see that the difference between man and the lower animals is one only of degree, quite as much as regards intellect as bodily form. I once saw exhibited in the _Jardin d’Acclimatation_, in Paris, a lot of Patagonian or Fuegan (I forget which) natives, who were very little superior intellectually to the chimpanzee. They were stark naked, in a wretchedly dirty condition, and appeared quite incapable of anything like sustained mental effort. But these are by no means the lowest among the human species.

In conclusion, I need only re-state my opinion that all so-called living things are but products of the development of protoplasm, whether belonging to the animal or vegetable kingdoms; that this protoplasm possesses the property of vitality, or the power of perceiving stimuli of various kinds and responding to them by definite movements; that the phenomena of mind are but functional manifestations of this protoplasmic development; and that the highest intellectual product of the human mind exists and has existed from eternity in a state of latent potentiality in every atom of protoplasm, as well as in every particle of matter in the universe.

THE SPECIAL SENSES.

According to the now almost universally (that is, among educated scientific people) accepted theory of Evolution, each living being upon this earth is a result of a very slow process of development, which commenced with a low form of life many millions of years ago, and has since been operating continuously, becoming more and more complex, and imperceptibly attaining greater perfection as each fresh stage was accomplished. From the homogeneous to the heterogeneous, from inorganic to organic, from Amœba to man, the evolutionary development has slowly, steadily, and surely advanced step by step, in obedience to certain well-defined laws. Yet it is impossible to discern in this slow process of evolution any well-marked difference between one particular species and the next of kin, although the difference becomes clearly apparent if we take two species separated from each other by considerable time; just as it is impossible to detect any alteration in form and feature between a child of six days old and the same child of seven days old, while the change is very evident after the lapse of several weeks or months. If we were to photograph a human being regularly each day from the moment of its birth to the time of its decease at the age of eighty, we should be unable to detect any real difference between the portraits on any two consecutive days; but the difference between the child of a week old and the young man of twenty years would be enormous, as would be that between the full-grown youth and the tottering old man. As the human individual in its earliest condition of existence is not possessed of the same faculties as it afterwards enjoys as a more perfect development, so, in like manner, the species in its primal condition was wanting in the loftier qualities now possessed by the higher animals, such as consciousness, sight, hearing, taste, smell, and touch, all of which have been gradually evolved as the various life-forms developed from lower and more simple to higher and more complex kind. For instance, at a very early period of man’s individual existence he possessed no brain, eyes, ears, mouth, or nose, and, therefore, was quite incapable of mentating, seeing, hearing, tasting, or smelling; but, as the organism very gradually developed into a higher and more complex kind, these various organs manifested themselves, and slowly arrived at such perfection as we find in the human infant at birth. Precisely so was it with the race. The lowly Moneron was of homogeneous structure, possessing neither parts nor kind, but gradually differentiating into nucleus and cell; its descendants, the Gastrœada, becoming possessed, by a process of invagination, of an external layer of nucleated cells and an internal and more delicate layer, thus forming a hollow organism, or Gastrula. This external cellular integument was the original sense-organ of the animal kingdom, from which developed the organs of special sense. Though without nerve and special sense-organs, yet these little hollow Gastrœada, and, in fact, their ancestors, the Amœbæ, which consisted of simple protoplasmic cells, each enclosing a nucleus, were possessed with sensory perception, being influenced by light, and by variations of pressure and temperature. As the evolutionary process continued, and the animal kingdom assumed higher forms, the original epidermal general sense-organ became converted into several special organs of sense, each specialisation commencing with a simple depression upon the integument of the organism; numerous little epidermal nerves of perception were formed, which could perceive changes of pressure and of temperature, and some of which gradually became enabled to understand particular influences affecting them, such as those produced by a strong odour, light-waves, and sound-waves. By adaptation, the extremities of these sense-nerves became expanded and enlarged, so as to enable them the better to understand the particular influences; and this expansion was accompanied by a corresponding depression on the integument, which cup-like formation afterwards became converted into an eye, or other organ of special sense, very imperfect in the invertebrate forms of life, imperfect in the fish, more perfect in the amphibian, and still more perfect in the mammal forms, such as apes and men. In short, the life-history of the individual is an exact counterpart in miniature of the life-history of the species up to the particular point reached by the particular individual.

The order and mode of development is precisely the same in all animal organisms, and may be conveniently studied by placing a hen’s egg in an incubating machine, and carefully watching it for the space of three weeks. It will be observed that the eye, ear, nose, and mouth are not present at the commencement of the process, but make their appearance later on, about the third or fourth day of incubation, as tiny depressions on the integument, from which condition they gradually develop into perfect organs of special sense, as possessed by the full-grown chicken; the eyes, which receive the impressions caused by light-waves; the ears, which receive those made by sound-waves; the nose, by which odours are discerned; the mouth, which holds the taste-organ; and the skin, which remains the organ of touch and perception of temperature. Now, when we consider for a moment these wonderful phenomena, we cannot help being struck by the remarkable manner in which the animal kingdom has been slowly and steadily progressing towards perfection, in spite of the enormous physical difficulties encountered; and we cannot help coming to the conclusion that, inasmuch as there was once a time when no animal existed having eyes, ears, nose, or mouth, and, still later, a period when these special sense-organs existed in a very imperfect condition, it is highly probable that in the future ages man, who now possesses special senses of a high order, will acquire even still more highly-developed faculties.

In congratulating ourselves upon the advance made by our own particular species over other members of the animal kingdom, we must never forget that, although we can mentate, see, hear, smell, taste, and feel, while myriads of our lowly brethren can do none of these, we yet are incapable of solving the mighty problems of the universe with any or all of these organs without artificial aid. No man on earth has ever yet been able to solve the mighty problem of existence, in spite of his great intellectual powers. No man has ever yet been able to see a millionth part of the wonders in the heavens above, or in the earth beneath, with his own unaided eye; but with the telescope and microscope new worlds have been opened out to him. We are as yet, undoubtedly, in but a transitory condition, the victims of an imperfect organisation, subject to a partially-developed brain and nervous system, and to five imperfect special senses. We must accept the situation philosophically, and without grumbling, and do our best to make good use of the senses we have, and leave the solution of problems we are unable to solve to future races of men, who will be possessed of better materials with which to operate.