Gradualism is often confused with the concept of phyletic gradualism. Darwin opposed saltation, insisting on gradualism in evolution as in geology (uniformitarianism). The study directly challenges phyletic gradualism and punctuated equilibrium. In 1710, Leibniz applied ideas of gradualism and uniformitarianism to linguistics in a short essay. The fossil record includes well documented examples of both phyletic gradualism and punctuational evolution. Machiavellian politics pushes politicians to espouse gradualism. Darwin opposed saltation, insisting on gradualism in evolution as in geology. The primary aspects of mutualism are free association, reciprocity and gradualism, or dual power. The advocation of gradualism distinguished this brand of socialism from those who favour revolutionary action. This is known as the principle of gradualism. It inaugurated a series by him on subitism and gradualism.