This is the seminal work in which Solovyov developed his religious philosophy. In it he undertakes a critique of positivism by which he understands the entire philosophy of western rationalism which he sees as setting up a conflict between reason and faith, and reason and nature. In the modern period he finds abundant evidence for reason's war against nature in western philosophy from Descartes to Hegel. "Positivism", the leading philosophy in his time, Solovyov also finds repungant. In its place, he proposes his great theme of total unity.