Volume 3 of 4. These volumes are based on the doctrine of evolution, with criticisms on the positive philosophy. They are based on the lectures given at Harvard University. At the outset, these lectures were designed only to include a criticism of the positive philosophy and when published, Fiske enlarged the course to make in include a somewhat complete outline sketch of the new philosophy based on the doctrine of evolution. The present volume contains Part II: Synthesis (continued). Illustrated.