 The “Natural Selection” manuscript also contained some new theoretical developments of relevance to the concept of natural selection that are not found in earlier manuscripts. Scholars have noted the introduction in this manuscript of the “principle of divergence”, the thesis that organisms under the action of natural selection will tend to radiate and diversify within their “conditions of life”—the contemporary name for the complex of environmental and species-interaction relationships (Kohn 1985b, 2008). Although the concept of group divergence under the action of natural selection might be seen as an implication of Darwin’s theory from his earliest formulations of the 1830s, nonetheless Darwin’s explicit definition of this as a “principle”, and its discussion in a long later insertion in the “Natural Selection” manuscript, suggests its importance for Darwin’s mature theory. The principle of divergence was now seen by Darwin to form an important link between natural variation and the conditions of existence under the action of the driving force of population increase.