 The primary distinguishing feature of Darwin’s theory that separates it from previous explanations of species change centers on the causal explanation he offered for how this process occurred. Prior theories, such as that of Jean-Baptiste Lamarck, relied on the inherent dynamic properties of matter, or in some of the German reflections, on special dynamic forces, such as those building upon the “Formative Drive” (Bildungstrieb) theory of Johann Blumenbach (1752–1840) (Zammito 2018: chps. 7–9). The change of species was not, in these pre-Darwinian efforts, explained through an adaptive process. Darwin’s emphasis after Notebook D on the factors controlling population increase, rather than on a dynamic theory of life grounded in vital forces, however, accounts for many of the differences between Darwin’s theory and those of his predecessors and contemporaries.