Rudolf Eucken centered his philosophy on the human experience. He maintained that man is the meeting place of nature and spirit and that it is man's duty to overcome his nonspiritual nature by actively striving after the spiritual life. Some of his major works are Die Einheit des Geisteslebens (The Unity of the Spiritual Life, 1888), Geistige Strömungen der Gegenwart (Main Currents of Modern Thoughts, 1908), Der Sinn und Wert des Lebens (The Meaning and Value of Life, 1908), and Der Sozialismus und seine Lebensgestaltung (Individual and Society, 1923).[2][3]