Page:Mind (New Series) Volume 9.djvu/235

 VITALISM : A BRIEF HISTORICAL AND CRITICAL REVIEW. 221 only remains to present the generally received notions of his views. In a well-known passage, Hippocrates ascribes the essence of life and the cause of all its phenomena to the ether, the subtle fire which has existed from all eternity and is present in air and all matter. This fire or ether, which seems identical with the pneuma elsewhere described, is im- mortal, knowing, seeing and hearing all. It knows the present, past and future ; it arranges everything, working noiselessly, being neither tangible nor visible. The pneuma changes between the lungs and the blood, between the blood and the tissues : the brain communicates with it freely. Soul and life seem to be made up of this atmosphere, which diffused through nature is single in essence though manifold in qualities. At length we come to him who was the first clearly to separate mind from body, who enlarged chereby the whole field of philosophic inquiries Plato (427-344 B.C.). Because of the far-reaching influence which his cosmogony held over his own and on long subsequent physiology, a clear account of the Platonic philosophy would have great value. The task, however, is well-nigh impossible amid so much allegory, so marked a want of coherence, and such frequent contra- dictions as are found scattered throughout his works. Plato has been excused these obscurities on the ground that they in reality express the scepticism of the Socratic school to which he belonged. Whether this be so or not, the result has been that each age places a different interpretation on his works. The system of Plato is founded on the distinction between Being and Not-Being, and the universe is accordingly divided into a region of noumenal intelligible Ideas and a region of phenomenal sensible matter. Ideas alone have true Existence. Phenomena are considered as lying midway between that which has and that which has not Existence. At the opposite extreme of Being stands that " which is at once the groundwork and the receptacle of all Becoming, the common element which underlies all corporeal elements and all determinate matter ". (2) Whether this groundwork of phenomena was conceived by Plato as a material substance has been disputed. But surely the admittedly unknowable nature of the Not-Being demonstrates its formlessness. Plato has often been credited with the separation of soul from life in contradistinction to Aristotle who, it has been said, maintained that they were one. Yet in the Phcedo causes of life, places the De Natura Homin. as late as Herophilus. Haller denies the Hippocratic source of the De Significat. Vitx et Motug.