David, and of Amaury, caused the reaction of the first years of the 13th century against Aristotle. Amaury seems indeed to have cleared out Christian dogma pretty thoroughly, and to have preached the coming of science as the “third age” of the world. Many of his followers were sent to the stake; by the Synod of Paris (1209) the works of Aristotle were proscribed, and many copies of them burned. This proscription was virtually withdrawn by Gregory the Ninth in 1231; and Hales, Albert and St Thomas devoted themselves again to the study of Aristotle, and established his supremacy[21]. Indispensable then as realism was for the Church, its creed, and its sacraments, yet therein it found itself in a dilemma between the conceptions of a Creator working under conditions, and of a spirit immanent in matter; and when theological philosophy culminated in St Thomas, and was fixed by him as it now rules in Rome, this difficulty was rather concealed in his system than resolved[22]. Every scheme of thought must make some declaration on the nature and place of universals; the problem was no hair splitting[23], it dealt with the very nature and origin of being; it agitated the minds of thinking men at a time of the most fervid and widespread enthusiasm for knowledge which the Western world has ever known,—at a time when Oxford counted its students by thousands, and when in Paris a throng athirst for knowledge would stretch from the cloisters of the Mathurins to the faubourg of St Denis[24]; and, in respect of our theme of this day, we shall see that even Harvey was embarrassed by certain aspects of it. For, to resume, closely allied to the argument concerning universals was that concerning “form and matter.” Whether the terms used were “form and matter,” force or energy or “pneuma” and matter, “soul or life” and “body,” “determinative essence and determinate subsistence,” “male principle and female element,” “archæus and body,” the potter and the clay of the potter; or whether again they were “type and individual,” “cause and effect,” “law and nature,” “becoming and being,” or even the “thought and extension” of Descartes, the riddle lay in the contrast of the static and dynamic aspects of things; in the incessant formation of variable and transitory individuals in the eternal ocean of existence[25]. “Spiritus intus alit, totamque infusa per artus Mens agitat molem, et magno se corpore miscet.”