194 THE AMERICAN JOURNAL OF SOCIOLOGY
tudes of men through centuries to the spell of his purpose or ideal. For every genius whose name is remembered a hundred minor innovators have fallen into oblivion. As for the leader, he accomplishes nothing without the consent of the led.
There are, in brief, as many causes to a social phenomenon as there are human wills involved. Every free individual is a cause. If, nevertheless, it is possible to discern large and simple factors behind human affairs, it is because a few omnipresent needs or conditions or influences incline many wills in the same direc- tion. Just as a wave passes over a whe'at- field because the breeze strikes and bends every stalk, so a historical movement occurs because a common desire, dread, confidence, or admiration shapes the choices of multitudes of men. For the ultimate cause of a social manifestation must be motive or something that can affect motive.
The more minute the fact or relation we study, the more fre- quent will be the cases of its occurrence, and the more likely they are to be so similar that they can be treated as equivalents. The adoption of elementary units will therefore hasten the advent of the day when, by the simple counting of cases, we can measure the degree of agreement or repugnance between one kind of social phenomenon and another, or between a social phenomenon and a physical, vital, or psychical phenomenon. Only recently we have gotten new light by counting suicides, conversions, and lynchings. In time we shall tabulate feuds, mobs, insurrections, riots, revivals, custom imitations, mode imitations, race inter- marriages, etc. The statistical method, which enables us to measure social phenomena exactly and to substitute quantitative truths for qualitative, is an ideal instrument of precision, and is certainly destined to be applied to sociological problems in ways yet undreamed of.
" But what of the historical method?" I hear it said. "If you insist on the simple, how can you utilize the critical occa- sions, the momentous events, the dramatic facts furnished by the historian ? "
"History repeats itself." "History never exactly repeats itself." Here are two truths, the one the corner-stone of soci-
