50 THE AMERICAN JOURNAL OF SOCIOLOGY
fore, there has arisen the further question : Is there any explana- tion of revolutions in general? What is their significance in the social life-process? Have they any universal form or method of development, and is that method capable of scientific formu- lation ?
To have even asked these questions a score of years ago would probably have called forth a storm of ridicule. But such has been the progress of science that today many, if not most, social investigators would admit the possibility of finding univer- sal forms in social occurrences, and so in revolutions. If a digression may be permitted, I would say that this change of attitude on the part of scientific students of society is due largely to the progress of the science of psychology. The new functional psychology has proposed to interpret all mental life in terms of habit and adaptation; and the new psychological sociology, which is building itself up on the basis of the new psychology, proposes to do the same thing for the social life. Thus the possi- bility of finding universal forms for social occurrences on the subjective side, if not on the side of objective, environmental factors, is today more widely accepted than ever before. The reasons for the failure of the objective method of explaining social events are, indeed, now quite obvious. It is now seen that nearly all social occurrences are in the nature of responses to external stimuli. But these responses are not related, psychology tells us, to their stimuli as effects are to causes, as sociologists have so often assumed. The same response or similar responses may be called forth by very different stimuli, since the stimulus is only the opportunity for the discharge of energy. Conse- quently, any explanation of social occurrences in terms of exter- nal causes or stimuli is in a sense foredoomed to failure, since such an explanation will fall short of that universality which science demands. Hence the demands for a subjective or psycho- logical explanation of social phenomena, a demand which is being met today by the new psychological sociology. It is in accord- ance with this demand that I venture to offer a psychological theory of revolutions.
The theory of revolutions here presented was first formulated
