These examples will suggest the classes of phenomena to which I refer. It follows from these observations that when we find analogues of single traits of culture among distinct peoples, the presumption is, not that there has been a common historical source, but that they have arisen independently; and the theory suggests itself that a common cause accounts for the constant recurrence of these phenomena among the most varied members of mankind, no matter to what race they may belong.
Further investigation shows that these customs are not quite evenly distributed, but that certain more or less intimate associations exist between the industrial development, social organization, and religious beliefs of the peoples of the world; so that, among people with simple industries, thoughts are found that differ somewhat from those of people who have advanced further in the development of material culture. It has also been noticed that a relation exists between the ethnic life of a people and the geographical environment that favors or hinders their material development.
The common cause for this similarity of actions and beliefs of peoples and tribes widely separated, belonging to different races, and being on certain stages of cultural development, has been looked for in several ways.
Some investigators—like Ratzel, and in older times Karl Ritter and Guyot—have laid particular stress upon the influence of geographical environment upon the life of man, and emphasize those similarities which appear in similar types of environment.
Others believe that many of the customs, beliefs, and inventions common to people who live in regions far apart are an old heritage derived from the earliest times, when mankind was still confined to a small part of the earth’s surface.
Still others have tried to isolate the most generalized forms of similar ethnic phenomena. Bastian, the most important representative of this group of investigators, has called these forms “elementary ideas,” and has tried to show that they are unexplainable.
Psychologists finally have endeavored to explain the similarities by an analysis of mental processes.
It seems necessary to discuss these four methods of approach a little more fully.
It is not difficult to illustrate the important influence of geographical environment upon forms of inventions. The variety of habitations used by tribes of different areas offer an example of its influence. The snow house of the Eskimo, the bark wigwam of the Indian, the cave dwelling of the tribes of the desert, may serve as illustrations of the way in which protection against exposure is attained, in accordance with the available materials. Other examples may be found in the forms of more special inventions: as in the complex bows of the Eskimo, which seem to be due to the lack of long elastic material for bow-staves; and in the devices for securing elasticity of the bow where elastic wood is difficult to obtain, or where greater strength of the bow is required; and in the skin receptacles and baskets which often serve as substitutes for pottery among tribes without permanent habitation. We may also mention the dependence of the location of villages upon the food-supply, and of communication upon available trails or upon the facility of communication by water. Environmental influences appear in the territorial limits of certain tribes or peoples, as well as in the distribution and density of population. Even in the more complex forms of the mental life, the influence of environment may be found; as in nature myths explaining the activity of volcanoes or the presence of curious land forms, or in beliefs and customs relating to the local characterization of the seasons.
When, in our theories, we lay stress alone on observations which show that man is dependent upon geographical environment, and upon the assumption of a sameness or similarity of the mind in all races of mankind, we are necessarily led to the conclusion that the same environment will produce the same cultural results everywhere.