662 THE AMERICAN JOURNAL OF SOCIOLOGY
must be reached through the aid of social psychology. Illus- trations of the service which social psychology might render to economic science might be multiplied ad libitum. Among the more important questions which must receive, in whole or in part, a socio-psychological solution are those of distribution, of the rise and persistence of economic classes or groups, of the genesis and various expression of the so-called "economic instinct," and of the relation which various economic systems bear to the political, legal, and moral systems with which they are found. But perhaps enough has been said to show that economic science has much to expect from the development of a social psychology, and that its own progress in the future must be in an essentially socio-psychological direction.
In political science the need of the study of social psychology is not less evident. A host of questions concerning the origin and development of legal and political institutions await a socio- psychological settlement. Government and law are two of the most important products, or rather sides, of the social psychic process, and the attempt to understand them without under- standing it is like an attempt to understand an organic species without reference to organic evolution as a whole, or to explain attention without reference to the whole process of the mental life. The natural history of government and of the various forms of government, when it comes to be properly written, must seek the help of social psychology to explain the phe- nomena with which it deals. Monarchy, aristocracy, and democ- racy, with their variations and "perversions," will be truly explained as phenomena only when they are shown to be expressions of the particular psychical processes which charac- terize particular stages of social growth, or special social coordina- tions. The same method of interpretation will have to be applied to the legal systems and institutions which are bound up with government. It will be the further task of political science to show, through the facts of history and ethnography, what forms of government and of law are regularly associated with certain types of social psychic coordination. Thus it is possible that some degree of prevision may be reached as regards the relation
