Schopenhauer, Darwin : both thinkers are inspiring figures at the end of the 19th century and their views regarding the nature, origin and future of humanity have largely come to dominate in an atmosphere of epistemological rupture, pessimism and loss f faith in the ideal of science-driven progress. Two thinkers who in their time had disrupted the most entrenched illusions regarding order, necessity, reason, and time even. Since their meeting, far from being regarded with suspicion, seems completely logical in the 1890s, we have judged it interesting to examine the bridge thus built between philosophy and biology, and explore the nature of such a transfer, typical of the 19th century, to a world-view deeply influenced by the biological sciences, as well as its legacy, imaginary and imagined, among the writers of the end of the century.