  Human conduct is subject to the “primary” rhythms of physical law, as well as to the “secondary” rhythms of social regularities; social regularities exhibit “nearly” the same uniformity as physical law, and they are also “liable to stoppage and change” (ca. 1905, 278). Aspiring to unite the Geisteswissenschaften and the Naturwissenschaften—“the science of man and physical science”—Du Bois characterizes sociology as “assuming the data of physics and studying within these that realm where determinate force is acted on by human wills, by indeterminate force” (ca. 1905, 277–278).