Darwin and Nietzsche on Genealogy

Taking a genealogical approach to an idea -- what is its lineage, family tree, or antecedent chain of births? -- is not new.  Jean-Jacques Rousseau had arguably taken a similar approach to moral degradation and inauthentic living in his "Discourse on the Origin of Inequality" (1754).  (See, e.g., two prior notes on this, here and here.)  It does seem, however, that genealogy more explicitly comes into its own as a method of inquiry in the nineteenth century.  Sigmund Freud himself later will follow much the same path in Civilization and Its Discontents (1930).  When one reads Freud's exploring the genealogical history of human unhappiness with civilization, which he explains by tracing the evolution of guilt in the development of the super-ego, one detects not only the influence of Rousseau's incipient genealogical explorations, but also the more mature and distinct projects of nineteenth-century luminaries Charles Darwin and Friedrich Nietzsche.