Page:Greek Biology and Medicine.djvu/97

 Aristotle's biology crements of soul or life, possessed by each organism next higher in the universal series. Organic nature presented an ascending scale. If this organic world was not an evolution strictly speaking, it was not static. It was alive, in vital process, pressing on toward self- fulfillment through the purposeful power of nature. Each animal was formed and con- ducted to its end by the soul or life which was its purpose and design, its final cause. In like manner each organ was adapted to its function. The plastic power of serviceableness, of utility and use, the formation and existence of all parts as means to ends, with Nature ever work- ing toward an end and doing nothing vainly, — these convictions were launched by the great Stagyrite upon the mighty roles they were to play in all the subsequent thinking of man- kind. For " barren virgins," final causes were to have a large progeny! The principles of Aristotle are not dead. Changed scarcely in form, conceptions of the vital power of Nature have ever filled the minds of men and still live in the minds of those men of science for whom mechanics and chemistry cannot explain the world of life. Specific teleological explanations of function [75]