The reason the modern man is a more rational animal than his more primitive ancestor is possibly because he lives in a city, where most of the interests and values of life have been rationalized, reduced to measurable units, and even made objects of barter and sale. In the city—and particularly in great cities—the external conditions of existence are so evidently contrived to meet man’s clearly recognized needs that the least intellectual of peoples are inevitably led to think in deterministic and mechanistic terms. The embodiment of rational thought is the tool, the machine, in which all the parts are manifestly designed to achieve a perfectly intelligible end. The primitive man lives in a vastly different world, where all the forces about him are mysterious and uncontrollable, and where nature seems as wild, as romantic, and as unpredictable as his own changing moods. The primitive man has almost no machinery, and relatively few tools. The mentality of the modern man, on the other hand, is based upon the machine and upon the application of science to all the interests of life—to education, to advertising, and, presently, perhaps, to politics. The culture of the modern man is characteristically urban, as distinguished from the folk culture, which rests on personal relations and direct participation in the common life of the family, the tribe, and the village community. In fact, if we define them strictly, as Lévy-Bruhl seems to do, we may say that reason and reflective thinking were born in the city. They came, if not into existence, at least into vogue, in Athens, in the time of Socrates and the Sophists. The Sophists were, in fact, a distinctly urban phenomenon, and we owe to Socrates—who was one of them—the first clear recognition of conceptional, as distinguished from perceptional, knowledge. We owe to Plato, Socrates’ disciple, the definition of the most fundamental tool of modern scientific thought, namely, the concept, i.e., the Platonic idea. Magic may be regarded, therefore, as an index, in a rough way, not merely of the mentality, but of the general cultural level of races, peoples, and classes. It is even possible that a more thoroughgoing analysis of the mental processes involved in magic and rational thought will permit us to measure the mentalities of social groups with as much precision, at least, as we now measure and grade—with the aid of the Binet-Simon tests—the intelligence of individuals. At least we should know in this case what we were measuring, namely, the extent and degree to which a given group or class had acquired the ability and the habit of thinking in rational rather than magical terms.