Starting with a close analysis of Humboldt's famous Kosmos, this study discusses the genealogy of Modern Esotericism and its relations to contemporary fiction. As part of the antimaterialist movement in the 19th century, the works of Carl Gustav Carus, Gustav Theodor Fechner, Ernst Haeckel and Hanns Hörbiger try to establish a modernist philosophy of nature, which became highly influential both in modern history of science and in popular esotericism.