Starting with a close analysis of Humboldt's famous Kosmos, this study discusses the genealogy of modern esoteric cosmography and its relations to 19th century fiction. As part of the antimaterialist movement since the 1840s, the esoteric works of Carl Gustav Carus (physiologist and painter), Gustav Theodor Fechner (founder of psychophysics), Ernst Haeckel (propagator of Darwinism), and Hanns Hörbiger (founder of the World Ice Theory) try to establish a modernist philosophy of nature, which became highly influential both in modern esotericism and scientific discourse, as well as in contemporary fiction.