Double (n.) is a threat by its mere existence: even a clipped fingernail is a potential double, and so a seed of violence.
Double (n.) are what rivals become once the prize drops from view: nothing in their antagonism tells them apart.
Double (n.) are rivals of whom nothing can be said of one that must not be said of the other; each occupies every position in turn, then all at once.
The Double (n.) of the Romantics and of Freud and Rank — mirror image, ghost, hallucination — goes back to real doubles: rivals locked in reciprocal violence they do not understand.
Double (n.) is for Freud an image or a ghost from a mythical past, never what it is: a real other, a mimetic adversary.
Double (n.) link the persecutors who are persecuted and the persecuted who persecute; the possessed imitates the stoners and they imitate him.