Johann Friedrich Blumenbach is widely known as the father of German vitalism and his notion of Bildungstrieb, or nisus formativus, has been recognized as playing a key role in the debates about generation in German-speaking countries around 1800. On the other hand, Caspar Friedrich Wolff was the first to employ a vitalist notion, namely that of vis essentialis, in the explanatory framework of epigenetic development. Is there a difference between Wolff’s vis essentialis and Blumenbach’s nisus formativus? How does this difference (...) influence their overall understanding of the epigenetic process? The paper aims to provide an answer to these questions through the analysis of a little-known document, which contributes to shed light on a crucial chapter of the German life sciences in the late eighteenth-century, namely the decisive phase of the process that led to the formalization of biology as a unified field of inquiry at the beginning of the nineteenth century. (shrink)

Historians have often described embryology and concepts of development in the period around 1800 in terms of “temporalization” or “dynamization”. This paper, in contrast, argues that a central epistemological category in the period was “rhythm”, which played a major role in the establishment of the emerging discipline of biology. I show that Caspar Friedrich Wolff’s epigenetic theory of development was based on a rhythmical notion, namely the hypothesis that organic development occurs as a series of ordered rhythmical repetitions and variations. (...) Presenting Christian Heinrich Pander’s and Karl Ernst von Baer’s theory of germ layers, I argue that Pander and Baer regarded folding as an organizing principle of ontogenesis, and that the principle’s explanatory power stems from their understanding of folding as a rhythmical figuration. In a brief discussion of the notion of rhythm in contemporary music theory, I identify an underlying physiological epistemology in the new musical concept of rhythm around 1800. The paper closes with a more general discussion of the relationship between the rhythmic episteme, conceptions of life, and aesthetic theory at the end of the eighteenth century. (shrink)