On learning that Alexander von Humboldt's health had worsened, Darwin wrote to his friend Joseph Hooker, then in Paris:

Alexander von Humboldt – romantic adventurer, friend of Goethe, and the very doyen of German science in the first half of the nineteenth century – had preceded Darwin to the Americas. He wrote of his explorations in Personal Narrative of Travels to the Equinoctial Regions of the New Continent, during the Years 1799–1804, and elaborated their findings in his greatly celebrated Cosmos. These two multivolume books had a tremendous impact on Darwin and helped forge the romantic conception of nature that underlay his theory of evolution. That romantic conception reveals itself most perspicuously in the moral evaluation of nature and man that Darwin plaited through his two principal works: the Origin of Species and the Descent of Man.

Darwin's conceptions of nature and man have, of course, typically been regarded as the very antithesis of the romantic. The moral theory most often ascribed to him harks back to Hobbes: ethical propositions are presumed to be merely flimflam for efforts at selfish aggrandizement.