Although Greg argued that an editor should be free to use his judgment to choose between competing substantive readings, he suggested that an editor should defer to the copy-text when "the claims of two readings ... appear to be exactly balanced. ... In such a case, while there can be no logical reason for giving preference to the copy-text, in practice, if there is no reason for altering its reading, the obvious thing seems to be to let it stand." The "exactly balanced" variants are said to be indifferent.
Are there times when an editor's judgement should be deferred? (If the question is unanswerable, say "unanswerable")
the claims of two readings ... appear to be exactly balanced