And at first sight a suspicion arises that the repetition shows the unequal hand of the imitator.

For why should a writer say over again, in a more imperfect form, what he had already said in his most finished style and manner?
And yet it may be urged on the other side that an author whose original powers are beginning to decay will be very liable to repeat himself, as in conversation, so in books.

He may have forgotten what he had written before; he may be unconscious of the decline of his own powers.

Hence arises a question of great interest, bearing on the genuineness of ancient writers.

Is there any criterion by which we can distinguish the genuine resemblance from the spurious, or, in other words, the repetition of a thought or passage by an author himself from the appropriation of it by another?
The question has, perhaps, never been fully discussed; and, though a real one, does not admit of a precise answer.