Prologue; Part I; Preface to the first part; 1. A critical essay on the philosophy of history; 2. 'Mind-stuff' from the historical point of view; 3. Giordano Bruno; 4. The musical and the picturesque elements in poetry; 5. On the nature of thought; 6. Philosophical antinomies; 7. Giordano Bruno and his time; 8. The problem of causality; 9. Science and idealism; 10. Correspondence; Part II; Preface to the second part; 11. Apollonius of Tyana; 12. Celsus and Origen; 13. Origen as philosopher; 14. John Scotus Erigena; 15. Nicholas of Cusa; 16. Animism, religion and philosophy; 17. A compendious classification of the sciences; 18. Teleology and the individual; 19. A new metaphysic of evolution; Appendix.