In Schelling's and Hegel's philosophy, new approaches can be found for the determination and systematic classification of the concepts of space and time. The author explores how these philosophical ideas of space and time have developed in German natural philosophy after Schelling and Hegel. In particular, the influences of Hegel and Schelling on the philosophy of Hermann Lotze are highlighted. By comparing the development of the physical concepts of space and time with the historical emergence of Einstein's General Theory of Relativity, the proximity and distance between physics and natural philosophy become apparent. The analysis of Einstein's controversies with colleagues presents the physical and philosophical issues that arise.