Philosophical or transcendental anatomy was a corner stone in the different visions of science which developed in the first half of the XIXth century. It is linked to a fundamental division in biologic sciences: whether animal structure should be explained by reference to function or by morphologic laws. In France, the scientific rivalry of Cuvier and Geoffroy Saint-Hilaire exemplified these two different conceptions and their confrontation culminated in a very acrimonious public debate before the Académie des Sciences de Paris in 1830. Cuvier’s aim was to establish a natural system of classification by treating anatomy in a comparative manner; he recognised four basic plans of organisation in the animal kingdom: vertebrate, articulate, molluscord and radiate branches. Cuvier also claimed that there were no transitions between these levels and that animal’s needs, adapted to its environment, determine its structure.