I Q2 THE AMERICAN JOURNAL OF SOCIOLOGY
Every martial invention, according as it has favored the Attack or the Defense, has disturbed the balance between great states and small states, between central government and local groups, between exploiters and exploitees. Next rank the inventions that have facilitated transportation and communication wheeled vehicle, boat, sail, compass, rail, steam. Besides their obvious economic effects, these have called into being that center of radiation, the city, promoted far-reaching diffusions and rapid assimilations, hastened blendings of blood and crossings of cul- tures, abolished frontiers, widened the areas of peace, favored the formation of vast political units, and superseded local asso- ciation by national and international association. More than this, they necessarily accelerate progress by merging the peoples into a great human ocean that promptly transmits to all parts all the progressive impulses arising in each of the parts. Thus, at last, every portion of mankind is served, not only by its own inventive spirits, but by all the productive geniuses of humanity. Finally come the condition-making inventions embodied in languages, sciences, and speculations. Languages support the inter-mental activities by which large groups of like-minded are formed. The building of physical concepts and generalizations is indispensable to the progress of mechanical invention. Speculations regarding the Unseen have been of utmost moment, because they determine to what extent institutions and groupings shall be bound up with the gods. After a certain stage of conceptual thought is reached, the revolutions in ideas wrought by prophets and founders of religion become almost as striking in their social effects as the revolutions in the mode of production wrought by inventors.
Not always, however, are the social transformations wrought by innovators unintended by-products. In some cases a new institution, relation, or grouping springs directly from the indi- vidual mind. The Hebrew prophets who originated worship without sacrifice, and the Reformers who proclaimed "justifica- tion by faith," consciously severed the tie that binds layman to priest. With his principle that the ties of kinship should be wholly subordinated to the ties of belief, Mahomet gave a new basis to Arab society. Caesar was a social inventor when he
