He [Augustine] anticipated Descartes’ “Cogito, ergo sum”: to refute the Academics, who denied that man can be certain of anything, he argued: “Who doubts that he lives and thinks? … For if he doubts, he lives.”  He presaged Bergson’s complaint that the intellect, through long dealing with corporeal things, is a constitutional materialist; he proclaimed, like Kant, that the soul is the most directly known of all realities, and clearly stated the idealistic position—that since matter is known only through mind, we cannot logically reduce mind to matter.  He suggested the Schopenhauerian thesis that will, not intellect, is fundamental in man; and he agreed with Schopenhauer that the world would be improved if all reproduction should cease. 
 De Trin., x, 10.
 Ibid, viii, 6; Confessions, x, 6.
 De bono conjugali, x; Figgis, J. N., Political Aspects of St. Augustine’s City of God, 76; Lea, H. C., Sacerdotal Celibacy, 47.
Source: Durant, Will. The Age of Faith, “The Progress of Christianity” (V. St. Augustine (354-430), 3. The Philosopher). p.71 1950. Simon and Schuster, Inc.: New York 20, N. Y. (Rockefeller Center, 630 Fifth Avenue) 13th Printing.