A Serpent without Teeth. The Conservative Transformism of Jean-Baptiste d?Omalius d?Halloy (1783?1875)

Abstract

Abstract Historians dealing with evolutionary theory in the period between the death of Jean-Baptiste Lamarck (in 1829) and the publication of Charles Darwin’s The Origin of Species (in 1859) have mainly focussed on evolutionist radicals who were, for the most part, working at the margins of mainstream science. This essay, however, wants to indicate that in the same time period, a more moderate (even conservative) transformism was developed in the well-respected centres of scientific debate. It does so by concentrating on the intellectual trajectory of the Belgian Jean-Baptiste d’Omalius d’Halloy, not only a geologist of European reputation but also a noted conservative and catholic aristocrat. On the basis of previously unused archival material, this essay researches how d’Omalius developed his evolutionist ideas, starting from the lessons he took with Lamarck in the beginning of the 19th century and ending with the last transformist publications he published as a 90-year-old in the 1870s. Furthermore, the essay analyses how d’Omalius adapted Lamarck’s transformist ideas to his personal worldview and looks at the tactics he used to open a space for the evolution debate. In this way, it shows a largely unknown aspect of the transforming of transformism in mid-19th-century science.