The problem is made still more difficult by the dissemination of cultural elements from tribe to tribe, from people to people, and from continent to continent, which can be proved to have existed from the earliest times on. As an instance of the rapidity with which cultural achievements are transmitted may be mentioned the modern history of some cultivated plants. Tobacco and cassava were introduced into Africa after the discovery of America, and it took little time for these plants to spread over the whole continent; so that at present they enter so deeply into the whole culture of the negro, that nobody would suspect their foreign origin (Hahn). We find in the same way that the use of the banana has pervaded almost the whole of South America (Von den Steinen); and the history of Indian-corn is another example of the incredible rapidity with which a useful cultural acquisition may spread over the whole world. It is mentioned as known in Europe in 1539, and, according to Dr. Laufer, had reached China by way of Tibet between 1540 and 1570.

It is easy to show that similar conditions prevailed in earlier times. Victor Hehn’s investigations show the gradual and continuous increase of the number of domesticated animals and cultivated plants, due to their importation from Asia. The same process was going on in prehistoric times. The gradual spread of the Asiatic horse, which was first used as a draught animal, later on for riding, the spread of cattle over Africa and Europe, the development of European grains, may serve as illustrations. The area over which these additions to the stock of human culture were spread is very large. We see most of them travel westward until they reach the Atlantic coast, and eastward to the shores of the Pacific Ocean. They also penetrated the African Continent. It may be that the use of milk was disseminated in a similar way; for when the people of the world enter into our historic knowledge, we find milk used all over Europe, Africa, and the western part of Asia.

Perhaps the best proof of transmission is contained in the folk-lore of the tribes of the world. Nothing seems to travel as readily as fanciful tales. We know of certain complex tales, which cannot possibly have been invented twice, that are told by the Berbers in Morocco, by the Italians, the Russians, in the jungles of India, in the highlands of Tibet, on the tundras of Siberia, and on the prairies of North America; so that perhaps the only parts of the world not reached by them are South Africa, Australia, Polynesia, and South America. The examples of such transmission are quite numerous, and we begin to see that the early inter-relation of the races of man was almost world-wide.

It follows from this observation that the culture of any given tribe, no matter how primitive it may be, can be fully explained only when we take into consideration its inner growth as well as its relation to the culture of its near and distant neighbors, and the effect that they may have exerted.

It may be well to indicate here that there seem to have been two enormously large areas of extended diffusion. Our brief remarks on the distribution of cultivated plants and domesticated animals prove the existence of interrelations between Europe, Asia, and North Africa, from the Atlantic to the Pacific Ocean. Other cultural traits corroborate this conclusion. The gradual spread of bronze from Central Asia westward and eastward, all over Europe and over China, the area in which the wheel is used, where agriculture with plough and with the help of domesticated animals is practised, show the same type of distribution (Hahn). We may recognize the sameness of characteristic traits in this area also in other respects. Oath and ordeal are highly developed in Europe, Africa, and Asia excepting the northeastern part of Siberia, while in America they are hardly known (Laasch). Other common features of the cultural types of the Old World appear also most clearly by contrast with conditions in America. One of these features is the importance of formal judicial procedure in the Old World, and its almost entire absence among all the tribes of North and South America, who, in their general cultural development, might well be compared with the African negroes. In the domain of folk-lore I would mention the frequency of the riddle, the proverb, and the moralizing fable, which are so characteristic of an enormous part of the Old World, while they are lacking in northeastern Siberia and in America. In all these features, Europe, a large part of Africa, and Asia except in its extreme northeastern part, and its island connection east of the Malay Archipelago, form a unit.

In a similar manner we may trace certain very general traits over a large part of America. Most convincing among these is the use of Indian-corn all over that part of America in which agriculture is practised; but we might also mention the development of a peculiar type of ceremonialism and of decorative art. It would seem as though the middle parts of America had played a rôle similar to that of Central Asia in the Old World, in so far as many of the most characteristic traits of civilization may have had their home here before the higher type of Central American and South American civilizations were developed.

The third point of view is represented by Bastian, who recognizes the great importance of geographical environment in modifying the analogous ethnic phenomena, but does not ascribe to them creative power. To him the sameness of the forms of thought found in regions wide apart suggested the existence of certain definite types of thought, no matter in what surroundings man may live, and what may be his social and psychical relations. These fundamental forms of thought, “that develop with iron necessity wherever man lives,” were called by him “elementary ideas.” He denies that it is possible to discover the ultimate sources of inventions, ideas, customs, and beliefs, which are of universal occurrence. They may be indigenous, they may be imported, they may have arisen from a variety of sources, but they are there. The human mind is so formed that it invents them spontaneously, or accepts them whenever they are offered to it. Bastian’s theory of the permanence of these forms of thought seems to me related to Dilthey’s conception of the limitation of possible types of philosophy; and the similarity of lines of thought of these two men appears also clearly in Bastian’s constant references to the theories of philosophers as compared to the views held by primitive man. The important phenomenon in Bastian’s mind was the fundamental sameness of forms of human thought in all forms of culture, no matter whether they were advanced or primitive.

In the views as propounded by him, a certain kind of mysticism may be recognized, in so far as the elementary ideas are to his mind intangible entities. No further thought can possibly unravel their origin, because we ourselves are compelled to think in the forms of these elementary ideas.

To a certain extent a clear enunciation of the elementary idea gives us the psychological reason for its existence. To exemplify: The fact that the land of shadows is so often placed in the west suggests its localization at the place where the sun and the stars vanish. The mere statement that primitive man considers the animals as gifted with all the qualities of man shows that the analogy between many of the qualities of animals and human qualities has led to the view that all the qualities of animals are human. In other cases the causes are not so self-evident; for example, in the instance of widespread customs of restrictions of marriage which have puzzled many investigators. The difficulty of this problem is proved by the multitude of hypotheses that have been invented to explain it in all its varied phases.

The problem of the origin of elementary ideas has, however, been discussed from a psychological point of view; and the elaborate attempt by Wundt to work out a theory of folk-psychology, as well as the studies of psychological sociologists, indicate lines of attack of the problem. To illustrate this point, I may mention the general discussion of the function of association in the beliefs of primitive people, given by Wundt, or the study of suggestion and hypnotism in primitive life, made by Stoll. A more detailed discussion of this method of treatment of the common elementary ideas may be deferred until a later time (see [Chapter VIII]).