What, then, is the nature of the development of Greek thought, and in what respect does the Greek Systematic philosophy differ from the philosophy of the Greek Cosmologists? Greek philosophy in the Cosmological Period starts with a conception of an objective harmony of nature and spirit which is called hylozoism. Step by step in the Anthropological and Systematic Periods that harmony becomes broken into a dualism of mind and matter. The philosophy of this Systematic Period is a dualism of the parts of one objective world, not a subjective-objective antithesis. The realm of spirit lies side by side with that of nature, and the separation and alienation never reached the complete form that it did in the Middle Ages. The great Greek Systematizers in part represent this dualistic tendency, in part are a scientific effort to overcome it. “In spite of this tendency [to a dualism] the original presupposition [a harmony between nature and spirit] asserts itself in decisive traits; and we shall find that the true cause of its incapacity to reconcile these contradictions satisfactorily lies in its refusal to abandon that presupposition. When that [unity] is canceled, there remains to it no possible way of filling up a chasm which, according to its own standpoint, cannot exist.”[21] =A Summary of Greek Philosophy.= At this point a summary of Greek objective philosophy will be helpful. The philosophical problem that had been working itself out since Thales had been this: How may we think the Being that abides amid the changes of phenomena? The Cosmologists scrutinized physical nature and, without differentiating nature and spirit, conceived abiding Being to be living matter. The Anthropologists (except Socrates) doubted if there is any abiding Being. Among the Systematic Philosophers a dualism for the first time appears. Nature and spirit are differentiated, but both remain entirely objective. Democritus regarded the material universe as abiding Being, but in so large a way as to be able to construct upon it a psychology and an ethics. Plato found abiding Being in the realm of the spirit, in a group of moral and æsthetic entities. Aristotle attempts to overcome the opposition between materialism and Platonism. To him abiding Being is neither physical nature nor the spirit apart from physical nature. Abiding Being to Aristotle is the spirit _in_ nature. =Greek Philosophy (objective).= 1. The Cosmologists――Hylozoism. Abiding Being is living nature――some form of living matter. 2. The Anthropologists――Relativism (except Socrates). Being is not abiding, but consists of transitory mental states. This is a form of what was called by the schoolmen Nominalism, and summed up by the phrase _Universalia post rem_. 3. The Systematic Philosophers. Democritus――Materialism. Being consists in material atoms, but regarded in so large a way as to furnish a basis for a psychology and an ethics.