ARISTOTLE AND THE CHURCH.--From the thirteenth century, Aristotle, completely known and translated into Latin, was adopted by the Church and became in some sort its lay vicar. He was regarded, and I think rightly, as of all the Greek thinkers the least dangerous to her and as the one to whom could be left all the scientific instruction whilst she reserved to herself all the religious teaching. Aristotle, in fact, "defended her from Plato," in whom were always found some germs of adoration of this world, or some tendencies in this direction, in whom was also found a certain polytheism much disguised, or rather much purified, but actual and dangerous; therefore, from the moment when it became necessary to select, Aristotle was tolerated and finally invested with office. ST. THOMAS AQUINAS.--As Aristotelian theologians must be cited William of Auvergne, Vincent of Beauvais, Albertus Magnus; but the sovereign name of this period of the history of philosophy is St. Thomas Aquinas. St. Thomas Aquinas wrote several small works but, surpassing them all, the _Summa_ (encyclopaedia) which bears his name. In general philosophy St. Thomas Aquinas is an Aristotelian, bending but not distorting the ideas of Aristotle to Christian conceptions. Like Aristotle, he demonstrated God by the existence of motion and the necessity of a first motive power; he further demonstrated it by the contingent, relative, and imperfect character of all here below: "There is in things more or less goodness, more or less truth." But we only affirm the more or less of a thing by comparing it with something absolute and as it approaches more or less to this absolute; there is therefore an absolute being, namely God--and this argument appeared to him better than that of St. Anselm, which he refuted. HIS CONCEPTION OF NATURE.--He showed the whole of nature as a great hierarchy, proceeding from the least perfect and the most shapeless to the most complete and determinate; from another aspect, as separated into two great kingdoms, that of necessity (mineral, vegetable, animal), and that of grace (humanity). He displayed it willed by God, projected by God, created by God; governed by God according to antecedent and consequent wills, that is, by general wills (God desires man to be saved) and by particular wills (God wishes the sinner to be punished), and the union of the general wills is the creation, and the result of all the particular wills is Providence. Nature and man with it are the work not only of the power but of the goodness of God, and it is by love that He created us and we must render Him love for love, which is involuntarily done by Nature herself in her obedience to His laws, and which we must do voluntarily by obedience to His commandments.