The theory of a continuous development from symbolic to realistic art is one of the numerous attempts to prove a continuous development of cultural forms, a steady, unbroken evolution. This view-point has had a deep influence upon the whole theory of ethnology. Evolution, meaning the continuous change of thought and action, or historic continuity, must be accepted unreservedly. It is otherwise, when it is conceived as meaning the universally valid continuous development of one cultural form out of a preceding type, such as the assumed development of economic forms from food gathering through herding to agriculture. In past times these three stages were assumed to be characteristic of all human development, until it was recognized that there is no connection between the invention of agriculture and the domestication of animals,—the former developed through the occupation of woman who gathered the vegetable food supply, the latter through the devotion of men to the chase. The men had no occasion to become familiar with the handling of plants, and the women had just as little opportunity of dealing with animals. The development of agriculture and of herding can, therefore, not possibly be derived from the same sources. It is no less arbitrary to assume that social forms must have developed in regular universally valid sequence, one certain stage always being based on the same preceding one in all parts of the world. There is no evidence that would compel us to assume that matrilineal organizations always preceded patrilineal or bilateral ones. On the contrary, it seems much more likely that the life of hunters in single family units, or that of larger groups in more fertile areas has led to entirely different results. We may expect continuous evolution only in those cases in which the social and psychological conditions are continuous.