Genealogy is gray, meticulous, and patiently documentary.  It operates on a field of entangled and confused parchments, on documents that have been scratched over and recopied many times.

On this basis, it is obvious that Paul Ree was wrong to follow the English tendency in describing the history of morality in terms of a linear development—in reducing its entire history and genesis to an exclusive concern for utility.  He assumed that words had kept their meaning, that desires still pointed in a single direction, and that ideas retained their logic; and he ignored the fact that the world of speech and desires has known invasions, struggles, plundering, disguises, ploys.  From these elements, however, genealogy retrieves an indispensable restraint: it must record the singularity of events outside of any monotonous finality; it must seek them in the most unpromising places, in what we tend to feel is without history—in sentiments, love, conscience, instincts; it must be sensitive to their recurrence, not in order to trace the gradual curve of their evolution, but to isolate the different scenes where they are absent, the moment when they remained unrealized…

Michel Foucault, “Nietzsche, Genealogy, History,” Section 1, 1971.