HYLOZOISM, in philosophy, a term applied to any system which explains all life, whether physical or mental, as ultimately derived from matter ("cosmic matter," Weldstoff) (Gr. dXn matter, -w17, life.) Such a view of existence has been common throughout the history of thought, and especially among physi cal scientists. Thus the Ionian school of philosophy, which began with Thales, sought for the beginning of all things in various material substances, water, air, fire (see IONIAN SCHOOL) . These substances were regarded as being in some sense alive, and taking some active part in the development of being. This primitive hylozoism reappeared in modified forms in mediaeval and Renais sance thought, and in modern times the doctrine of materialistic monism is its representative.