Statement that seems to contradict itself or common sense, but which, once thought through, reveals a truth.
In Crime and Punishment
Was it the old woman I killed? It was myself I killed, and not the old woman! Right there, all at once, I destroyed myself, forever!..
Saying that he killed himself “all at once, forever” while still speaking seems contradictory. The phrase affirms a death that is not of the body, and that is what makes it true for him.