What is history? How does it differ in its aims and methods from natural science, from political and economic science, from sociology? According to the new logic, the differences are fundamental. History concerns itself with the unique evolution of man in his activities as a social being. It deals with human potentialities in their teleological connections. Out of past social facts it selects the unique facts that have a value for the period that is being studied and groups these facts in complex, evolving wholes. History does not seek for what is common to the social facts of the past; it does not attempt to generalize, to establish laws. It could not if it would, for it deals with facts that have occurred but once, that will not occur again, and a generalization assumes repetition. The natural sciences, on the other hand, including economics, political science and sociology, deal with substances and causal law. They select for their syntheses what is common to a group of facts; they generalize, they aim to establish laws, to formulate the conditions under which a thing will repeat itself. Their ideal is the organization of reality under the point of view of the general. There is, of course, but one reality and natural science and history are simply two logical methods evolved by the human mind for the purpose of organizing it that it may be comprehended. The ends of the two methods are different, and their methods of getting at the truth are different. The student trained in the one method is not necessarily acquainted with the other. The Historian’s Work. The natural science method consists of a direct study of the facts, and, as it is not concerned with the unique as unique, it may create situations and conditions, thus securing abundant data for generalization. For the historian this is impossible. He studies not the fact, as the natural scientist studies plants, animals and chemicals in the laboratory; he has only the record of the fact, the fact itself having gone never to return. His knowledge of the fact will depend upon the abundance and value of the records the fact has left behind it. Such records we call sources. Sources, then, are the remains of man’s social activities. They fall naturally into two groups: remains and tradition. Remains consist of objects that were parts of the past event, and have survived the destructive action of time; tradition embraces the impressions of the event recorded by witnesses, and may be oral, written or pictorial in form. The historical reconstruction, found in the narrative text, is based, in a large majority of cases, upon written tradition.