Dalla scala all'anello: metafore e ostacoli epistemologici tra storia naturale ed evoluzionismo

This paper analyses the history and conceptual implications of two metaphors that pre-existed the reflections of modern biology and yet arrived in scientific discourse through the natural history of the 18th century. Integrating historical perspective and epistemology, the metaphor of the scala naturae and the image of the missing link are examined. The heuristic use of such images concerns the continuist and gradualist conception implicit in the accounts that have attempted to explain the transformations of living beings and their variety over the course of time; therefore, their historical coordinates are briefly reconstructed, analysing how their logic came to be applied to the monophyletic conceptions of human evolution during the 20th century. On closer inspection, as knowledge has increased, the metaphors proved to be epistemological obstacles to the advancement of research and theories, as in the case of the nascent evolutionary theory, the effects of which spread as far as neo-Darwinism.