<P> While Wolff was not concerned to name this vital organising, reproducing power, in 1789 his successor at the Göttingen school of physiology, Blumenbach, posited a formative drive (nisus formativus or Bildungstrieb) responsible for biological "procreation, nourishment, and reproduction," as well as self - development and self - perfection on a cultural level . </P> <P> Blumenbach held that all living organisms "from man down to maggots, and from the cedar to common mould or mucor," possess an inherent "effort or tendency which, while life continues, is active and operative; in the first instance to attain the definite form of the species, then to preserve it entire, and, when it is infringed upon, so far as this is possible, to restore it ." This power of vitality is "not referable to any qualities merely physical, chemical, or mechanical ." </P> <P> Blumenbach compared the uncertainty about the origin and ultimate nature of the formative drive to similar uncertainties about gravitational attraction: "just in the same way as we use the name of attraction or gravity to denote certain forces, the causes of which however still remain hid, as they say, in Cimmerian darkness, the formative force (nisus formativus) can explain the generation of animals ." </P> <P> At the same time, befitting the central idea of the science and medicine of dynamic polarity, it was also the physiological functional identity of what theorists of society or mind called "aspiration ." "Blumenbach's Bildungstrieb found quick passage into evolutionary theorizing of the decade following its formulation and in the thinking of the German natural philosophers (p. 245) </P>

Who is most associated with the taxonomy used by scientists today