This is Plato’s thought also when he objects to making knowledge mere sense-perception because it would make a different standard of knowledge for each man. Socrates in _Theaetetus_ quotes Protagoras on the same point: “Sensations are relative and individual.” One scarcely needs to be reminded here of Herder’s thorough acquaintance with Greek philosophy. The way from a sensation to thought is through the nerve-structure of sense organs, these nerve-structures furnishing just such a medium between the object of sensation on the one hand and thinking and willing on the other, as does light between the object of sense and the visual and auditory organs. Never losing sight of the physiological element in his psychology, Herder tells us that the soul has grown out of the body, and has so outgrown the body that soul has become the monarch over that, without which soul could not exist. All its thinking grows out of feeling, and this feeling out of a body having in its command manifold obscure forces administered to by variously endowed “servants” and “messengers.” III. KNOWING AND WILLING Herder denies that anything in the way of knowledge comes back to the soul out of the platonic fore-world, and abstract egoism, he says, is opposed to truth and the open course of nature. Just as all of the soul’s knowing depends upon obscure stimuli and forces having their foundations in the body and leading to sensations and then to reasoning, so her willing comes from these as a natural sequence of her knowing. Any knowing without willing would be false and incomplete. If knowing is only a deep feeling of truth, who is going to see truth and at the same time be blind to it—know goodness and not will to do it? Every single passion or feeling thus knowing the good would at the same time will the good. Herder is emphatic about the interdependence of these two. Just as no knowing is without willing, no willing is without knowing; they are only one energy of the soul. This suggests Socrates in the _Protagoras_, as he argues that men would always do good if they knew the good. “No man voluntarily pursues evil or that which he thinks to be evil. To prefer evil to good is not in human nature.” Briefly summarizing: Herder finds his _stimulus_ the same everywhere in the material world. It is the principle of life since it impels to self-nutriment and reproduction. It works by the same law in both body and soul. Variations of it in degree are the foundations for individuality and personality. All that is true of feeling for essentially stimulus becomes feeling. Out of all this Herder arrives at the conclusion: “Der tiefste Grund unseres Daseyns ist individuell, sowohl in Empfindungen als Gedanken.” The distinctive personal and individual character whose foundations have just been traced, according to our author, can not come to its fullest development except as a component part in a larger self-conscious and self-directing entity which he calls “humanity.”