Contamination in Manuscripts of the A-Text of Piers the Plowman
Theoretically it is true that the application of the genealogical method to a sizable number of manuscripts descended from a single archetype would allow the almost perfect reconstruction of that archetype. Families, groups, and subgroups could be distinguished without hesitation, and readings could be determined with very little recourse to editorial ingenuity. Unfortunately such conditions are not to be found in actual practice. When the text critic has made a systematic record of all variants to be found in the MSS that he has collated, he must determine which of the great quantity of variational groups are genetic—that is, which groups actually reflect in their common readings the genealogy of their transmission. This operation requires the elimination of variational groups formed by the mere possession of the right reading, and random groupings formed by the accidental coincidence of readings.