The same two currents in ethics which manifested themselves in Ancient Greece, continued to exist among the thinkers of later times up to the middle of the eighteenth century. A majority of philosophers and thinkers still sought the explanation of the origin of morality in something supernatural, revealed to man from above. The ideas of Plato, developed and strengthened by the Christian Church constituted, and still make up the essence of such teachings, save that they are considerably narrowed. Plato, as well as Socrates, considered the knowledge of good as the real motive force of all morality. But Plato did not present this knowledge as something acquired from without. At the base of Plato's teaching, and especially of the teaching of the Stoics, was the idea that the moral sense, which manifests itself in man, even if in imperfect form, is a part of some fundamental principle of the universe. If this element were not present in nature it would not manifest itself in m...