title: Mathematics Ab Ovo: Hans Driesch and Entwicklungsmechanik.
abstract: One of the factors leading to the creation of embryology as a modern discipline at the end of the 19th century was Wilhelm Roux's formulation of the program of Entwicklungsmechanik (developmental mechanics). A look into the work of Hans Driesch, an equal contributor to developmental mechanics, may shed further light on this process. For Roux, developmental mechanics was an anatomical science, but for Driesch it was associated with a mathematical and physical approach to the natural world. Likewise, Roux used the concept of mechanics as an analogy, but Driesch used it literally. Driesch's generation had been trained in a pedagogic context that emphasized mathematics and physics, which may explain why he went a step further than Roux to state that a true "mechanics" of development required the reduction of morphogenetic problems to the known laws of physics. It is argued here that this difference in background is behind the enthusiastic adoption and further development of Roux's program by Driesch's generation, a generation that conceived Entwicklungsmechanik to be the reduction of embryological processes to "the laws of matter in motion." This same mathematical and physical mindset would underscore Driesch's later construction of entelechy as a regulating factor in embryogenesis, through mathematical analysis grounded on the notion of mathematical functions.
authors.affiliation: Centro Simão Mathias de Estudos em História da Ciência, Pontifícia Universidade Católica de São Paulo, São Paulo, Brazil.
authors.forename: Silvia Waisse
authors.initials: SW
authors.lastname: Priven
authors.forename: Ana M
authors.initials: AM
authors.lastname: Alfonso-Goldfarb
mesh_terms: D000715:Anatomy / Q000266:history; D004626:Embryology / Q000266:history*; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D008433:Mathematics / Q000266:history*; D015046:Zoology / Q000266:history*