Part 4 (1/2)

Of the social animals, man presents the most complete type, and the one from which we can best deduce the conditions of the cla.s.s. A human community is made up of individuals of many degrees of intellectual ability, the ma.s.s remaining at a low level, the few attaining a high level. Yet those of high powers of intellect set the standard for the whole, teach the lower either by precept or example, and aid effectively in advancing the standard of the community. A rope or chain is said to be as weak as its weakest part. A human community, on the contrary, may be said to be as strong as its strongest part. The standing of the whole is dependent upon the thoughts and acts of the few, from whom the general ma.s.s receive new ideas and gain new habits. The existing intellectual and industrial position of mankind is very largely a result of ideas evolved by individuals age after age, and preserved as the mental property of the whole. Destroy the books and works of art and industry of any community, cut off its intellectual leaders, remove from the general mind the results of education, and it would at once fall back to a low level and be obliged to begin again its slow climb upward.

The intellectual standing of any civilized nation depends upon two things: the preservation in books, in memory, and in works of art and industry, of the ideas of ancient workers and thinkers; and the mental activity of living thinkers and inventors, whose work takes its start from this standpoint of stored-up thought. Rob any community of all its basic ideas, and it would quickly retrograde to a primitive condition of thought and organization, from which it might need many centuries to emerge.

It has been said above that man is the highest example of the social animal. While that is the truth, it is not the whole truth. He is at the same time the highest example of the communal animal. Mutual aid, organization into strictly rounded communities, labor for the good of the whole, is as declared in him as in the most developed community of the ants, and we admire the work of the latter simply because they repeat at a lower level the work of man. In truth, in man we have a splendid example of the existence of the individual initiative in connection with the communal organization. Specialism exists in a hundred forms. Some nations have been tied down by it to conditions almost as fixed as those of the ants. But generalism exists in as full a measure, new ideas are constantly modifying or replacing the old, and the communism of man is a progressive one, steadily borne upward on the wings of new ideas. Individual thought has the fullest swing, and it is to the system of special reward for useful thought and act that man owes much of his great advance. On the other hand, reward without useful service has been one of the leading agencies that have acted to check human progress.

The lower animals do not possess the advantage of man in his power of preserving the thoughts and products of the past as a foundation for new steps of progress. Memory may aid them to a slight degree, but they have no special means of recording useful ideas. This cannot fairly be said of the communal forms, which possess the result of the labors of former generations as useful object lessons. But in the higher animals no means exist for the permanent preservation of ideas, and each step of progress must be due to the direct influence of living individuals and the indirect result of natural selection.

This is one cause of the slow mental advance of the lower animals. A second is the deficiency in educational influences, which have had so much to do with human progress. Education is not quite wanting in the brute creation. There are many instances on record of instruction given by the adults to the young. But this agency is in its embryo stage, and its influence must be small. Again, each tribe of lower animals is apt to fall into a fixed circle of life acts, to become so closely adapted to some situation or condition that any change of habits would be likely to prove detrimental. This is a state of affairs tending to produce stagnation and vigorously to check advance. Many instances of this could be cited from human history, while it is the common condition with the animals below man.

To return to the apes, the considerations above taken lead to the conclusion that it is chiefly, if not solely, to their social habits that they owe their mental quickness. While only in minor traits communal, they are eminently social, and have doubtless derived great advantage from this. The lemurs, which share their habitat and resemble them in organization, are markedly unsocial, and are as mentally dull as the apes are mentally quick. Possibly, the thought powers of the apes once set in train, there may have been something in the exigencies of arboreal life that quickened their powers of observation; but we are constrained to believe that the main influence to which they owe their development is that of social habits, in which they stand at a high, if not the highest, level among the distinctly social animals.

The thought capacities of the ape intellect are general, not special.

The mind of these animals remains free and capable of new thought in new situations. It is fully alive to the needs and dangers of arboreal life, and advances no farther in its native habitat because there is nothing more of importance to be learned. But while fixed it is not stagnant.

When the ape is taken from its native woods and put among the many new conditions arising on s.h.i.+pboard and in human habitations, we quickly perceive indications of its mental alertness. Its faculties of observation and imitation are actively exercised, and new habits and conceptions are quickly gained. Could the apes be made to breed freely in captivity, so that a domestic race, comparable to that of the dogs, could be obtained, their mental powers might, perhaps, be cultivated to an extraordinary degree, yielding instances of thought approaching that of man. The ape is especially notable for its tendency to attempt new acts of itself, not waiting to be taught, as in the case of other domesticated animals. In short, it seems by all odds to be the animal best fitted mentally to serve as the basis of a high intellectual development, as it is the best fitted physically to change from the att.i.tude of the quadruped to that of the biped.

The anthropoid apes in general manifest a reversion from the social toward the solitary state, this condition reaching its ultimate in the orang, which is one of the most solitary of animals. The smaller forms are the most social, the gibbons being decidedly so. There is very good reason to believe that the man-ape was highly social, if we may judge from what we find in all races of men, and all grades, from the savage to the civilized. This animal was thus in a position to avail itself of all the advantages of the social habit, and to gain the mental development thence arising. How long ago it was when it left the trees and made its home upon the ground, it is impossible to say. It may have been as far back as the early Pliocene or the late Miocene Period, or even earlier. As yet its brain was probably no more developed than in the case of the other anthropoids, perhaps less so than in the existing species. But in its new habitat it was exposed to a series of novel conditions that must have exerted a healthful and stimulating influence upon its mind.

If it had remained in the trees we should probably to-day have only a man-ape still. Leaving their safe shelter for the ground, it became exposed to new dangers and was forced to fit itself to fresh conditions.

Prowling carnivorous animals haunted its new place of residence, and these it had to avoid by speed or alertness of motion, or combat them by strength and the use of weapons. The carnivorous tastes which it had in all probability gained, made it a creature of the chase, pursuing swift animals, capturing them by fleetness or stratagem, or bringing them down with the aid of clubs and missiles. Such a new series of duties and dangers could not fail to exert a vigorous influence upon a brain already quick of thought and susceptible to fresh impressions, and we may well conceive that the man-ape then entered upon a new and rapid phase of mental progress, its brain developing in powers and growing in dimensions as it slowly became adapted to its new situation and grew able to cope with fresh demands and critical exigencies.

There is still another influence which has had its share, perhaps a very prominent share, in the intellectual development of animals, yet which no writer seems to have considered from this point of view. The probable effect of this influence needs to be taken into account, in conclusion of this section of our subject. It is that of the comparative agency of the senses in the development of the mind, and the effects likely to arise from the dominance of some one of the senses.

In the lowest animals touch was the predominant, if not the only sense, taste perhaps being a.s.sociated with it. But these senses, which demand actual contact with objects, obviously could give none but the narrowest conception of the conditions of nature. The other senses, sight, hearing, and smell, give intimations of the existence and conditions of more or less distant objects, and their development greatly widened the scope of outreach in animals and must have exerted a powerful influence upon the growth of mental conditions.

It need scarcely be said that the sense which gives the fullest and most extended information about existing things is necessarily the one that acts most effectively upon the mind, and that this sense is that of sight. Hearing and smell yield us information concerning certain local conditions of objects, but sight extends to the limits of the universe, while in regard to near objects it has the advantage of being practically instantaneous in action and much fuller in the information it conveys. Sight, therefore, is evidently the most important of the senses, so far as the broadening of the mental powers is concerned, and any animal in which it is predominant must possess a great advantage in this respect over those species controlled to any great degree by one of the lower senses.

It may be said here that sight only slowly gained dominance in animal life. Though the eye, as an organ of vision, is found at a low level in the animate scale, the indications are that it long played a subordinate part, and has gained its full prominence only in man. During long ages life was confined to the sea, hosts of beings dwelling in the semi-obscurity of the under waters, and great numbers at too great a depth for light to reach them. To vast mult.i.tudes of these sight was partly or completely useless. The same may be said of hearing, the under-water habitat being nearly or completely a soundless one. The only one of the higher senses likely to be of general use to these oceanic forms is that of smell, and it may be that their knowledge of distant objects was mainly gained through sensitiveness to odors.

Of invertebrate land animals the same must be said. The land mollusks and the great order of insects and other land arthropods only to a minor extent dwell in the open light. Very many species haunt the semi-obscurity of trees or groves, hide among the gra.s.ses, lurk under bark, sticks, and stones, or dwell through most of their lives underground. Hosts of others are nocturnal. To only a small percentage of insects can sight be of any great utility, while hearing seems also to be of slight importance. Smell is probably the princ.i.p.al sense through which these animals gain information of distant objects.

There is existing evidence that the sense of smell in some insects is remarkably acute. The imprisoned female of certain nocturnal species, for instance, will attract the males from a comparatively immense distance, under conditions in which neither sight nor hearing could have been brought into play. The emission of odors and acute sensibility to them is the only presumable agency at work in those instances. As regards the most intelligent of the insects, the ants and the termites, the former are largely subterranean, the latter not only subterranean, but blind. In the one case, sight can play only a minor part, in the other, it plays no part at all. Touch and smell seem to be the dominant senses in these animals, and the degree of intelligence they display shows of how high a development these senses are susceptible. Yet the intelligence arising from them must necessarily be local and limited in its application; it cannot yield the breadth of information and degree of mental development possible under the dominance of sight.

In the vertebrates we find a fully developed and broadly capable organ of vision, and it might be hastily a.s.sumed that in those animals sight is the dominant sense. But there are numerous facts which lead to a different conclusion. Many of the vertebrates are nocturnal, many dwell in obscure situations, many in the total darkness of caverns, underground tunnels and excavations, or the ocean's depths. To all these sight must be of secondary importance. Hearing also can be of no superior value, and the dominant sense must be that of smell. In the bats there would appear to be a remarkably acute power of touch, if we may judge from the facility with which they can avoid obstacles at full flight after their eyes have been removed.

It might, however, be supposed that in the higher land vertebrates sight is predominant, and that the diurnal mammals depend princ.i.p.ally upon their eyes for their knowledge of nature. But there are facts which throw doubt upon this supposition. These facts are of two kinds, external and internal. That the quadrupeds, in general, are highly sensitive to odors is well known, and also that they trust very largely to the sense of smell. Hunters are abundantly aware of this, and have to be quite as careful to avoid being smelt by their game as to avoid being seen. We have abundant evidence of the remarkable acuteness of this sense in so high an animal as the dog, which can follow its prey for miles by scent alone, and can distinguish the odors, not only of different species, but of different individuals, being capable of following the trail of one person amid the tracks of numerous others.

The internal evidence of this fact is equally significant. In the vertebrates, in general, the olfactory lobe of the brain is largely developed, much exceeding in size the lobe of the optic nerve. It forms the anterior portion of the cerebrum, and in many instances const.i.tutes a large section of that organ, being marked off from it by only a slight surface depression. If we can fairly judge, then, by anatomical evidence, the sense of smell plays a very prominent part in the life of all the lower vertebrates. If we take our domestic animals as an example, the olfactory lobe of the horse is considerably larger than that of man, though the brain, as a whole, is very much smaller, so that, comparatively, this organ const.i.tutes a much larger portion of the total brain. The other domestic animals yield similar evidence of the great activity of the sense of smell.

While there is no doubt that sight is an active sense in all the higher quadrupeds, it evidently divides this activity with smell to a much greater degree than is the case with man, in whom smell plays a minor part, sight a major part, among the organs of sense.

This fact shows its effect in the comparative mental development of man and the lower animals. Man, depending so largely on vision, gains the broadest conception of the conditions of nature, with a consequent great expansion of the intellect. The quadrupeds, depending to a considerable degree upon smell for their conceptions of nature, are much narrower in their range of information and lower in their mental development. As regards the ape family, it occupies a position between man and the quadrupeds, and its intellectual activity may well be due in great measure to an increased trust in sight and a decreased trust in smell in gaining its conception of nature.

The question may arise, Why, if sight has this superiority over smell, did it not long since gain predominance, and relegate smell to a minor position? It may be answered that the superiority of sight is not complete. In one particular this sense is inferior to smell. The leading agency in the development of the sense organs of animals has been the struggle for existence, including escape from enemies, and the perception of food-animals or material. In these processes acuteness of smell plays a very important part. It has, moreover, the advantage of gathering information from all directions, while sight is very limited in its range. The eye is so subject to injury that its multiplication over the body would be rather disadvantageous than otherwise, while, localized as it is, a movement of the head is necessary to any breadth of vision, and the whole body must rotate to bring the complete horizon under observation. It seems evident, from these considerations, that sight is much inferior to smell in the timely perception of many forms of danger. Light comes in straight lines only, and a movement of the body is necessary to perceive perils lying outside these lines. Odors, on the contrary, spread in all directions, and make themselves manifest from the rear as well as the front.

In all probability this fact has had much to do with the continued dependence of animals on smell. In fishes and reptiles a full sweep of vision is so slowly gained that some more active sentinel sense is requisite to safety. In mammals the head rotates more easily, but valuable time is lost in the rotation of the whole body. These animals, therefore, depend on both sight and smell, in some cases equally, in some more fully on one or the other of these senses. When we reach the semi-upright ape, we have to do with a form capable of turning the body and observing the whole surrounding circle of objects more quickly and readily than any quadruped. As a result, these animals have grown to depend more fully on vision and less on smell than the quadrupeds.

Finally, in fully erect man, the power of quick turning and alert observation of the whole circle of the horizon reaches its ultimate, and in man sight has become in a large degree the dominant sense, and smell has fallen to a minor place.