In the edition of the Natiirliche Schopfungsgeschichte published in 1868 he made a great advance in his genealogical classification, since he now introduced the results of the extraordinary activity in the study of embryology which followed on the publication of the Origin of Species.
Among his works are Kapital and Arbeit (1865); Der Wert des Lebens (1865); Natiirliche Dialektik (1865); Kritische Geschichte der Philosophie (1869); Kritische Geschichte der allgemeinen Principien der Mechanik (1872) - one of his most successful works; Kursus der Nationaland Sozialokonomie (1873); Kursus der Philosophie (1875), entitled in a later edition Wirklichkeitsphilosophie; Logik and Wissenschaftstheorie (1878); Der Ersatz der Religion durch Vollkommeneres (1883).
His earlier work, Natiirliche Dialektik, in form and matter not the worst of his writings, is entirely in the spirit of the Critical Philosophy.
1799); System des transcendentalen Idealismus (Tubingen, 1800); Bruno, oder fiber das gottliche and natiirliche Prinzip der Dinge (Berlin, 1802, ed.
Die natiirliche Tochter (1803), in which he began to embody his ideas of the Revolution on a wide canvas, proved impossible on the stage, and the remaining dramas, which were to have formed a trilogy, were never written.
Goethe's classic principles, when applied to the swift, direct art of the theatre, were doomed to failure, and Die natiirliche Tochter, notwithstanding its good theoretic intention, remains the most lifeless and shadowy of all his dramas.