Jean Jacques Rousseau
Rousseau's influence on posterity has been equaled by only a few, and it is by no means spent. His influence on German and English romanticism—and thus, indirectly, on romanticism in general—is difficult to overestimate. In addition, men as diverse as Immanuel Kant, Johann Goethe, Maximilien de Robespierre, Johann Pestalozzi, and Leo Tolstoy have been his disciples. His doctrine of popular sovereignty had a profound impact on French revolutionary thought. Although he did not advocate collective ownership, his ideas also had their effect on socialist thought. It is probably more correct to say that he anticipated rather than influenced many insights of modern social psychology.