 The scholarly reconstruction of Darwin’s methodology employed in the Origin has taken two primary forms. One approach has been to reconstruct it from the standpoint of currently accepted models of scientific explanation, sometimes presenting it as a formal deductive model (Sober 1984). Another, more historical, approach interprets his methodology in the context of accepted canons of scientific explanation found in Victorian discussions of the period (Ruse 2013b; Waters 2003; Hull 2003; Lewens 2008; Ruse 2008; Lennox 2005; Hodge 1983b). The degree to which Darwin did in fact draw from the available methodological discussions of his contemporaries—John Herschel, William Whewell, John Stuart Mill—is not fully clear from available documentary sources. The claim most readily documented, and defended particularly by M. J. S. Hodge (1977, 1983a), has emphasized the importance of John Herschel’s A Preliminary Discourse on the Study of Natural Philosophy (1830), which Darwin read as a young student at Cambridge prior to his departure on the HMS Beagle in December of 1831. In Herschel’s writings he would have encountered the claim that science seeks to determine “true causes”—verae causae. This concept Newton had specified in the Principia as the third of his “Rules of Reasoning in Philosophy” (see the entry on  Newton’s philosophy,    Section 4). This was to be the goal of scientific explanation. Such causes, in Herschel’s formulation, were those necessary to produce the given effects; they were truly active in producing the effects; and they adequately explained these effects (Herschel 1830; Lennox 2005; Waters 2003). These criteria distinguished a satisfactory scientific account from the simple “saving of phenomena” by plausible explanations in the tradition of scientific conventionalism. The impact of Herschel’s arguments on Darwin’s intellectual development was evidently profound, although there is no direct textual reference to Herschel’s concept of a vera causa itself in the Notebooks and other early writings.