From VN's short-story ( originally written in English) Scenes from the Life of a Double Monster  (casually introduced in the list by A.S and M.R and superficially explored by me) I selected two sentences.

 

The first one was quoted already (the aitch would see an eye, the Roman two a one, the scissors a knife).

The second: " When, for example, one of us was about to stoop to possess himself of a pretty daisy and the other, at exactly the same moment, was on the point of stretching up to pluck a ripe fig,individual success depended upon whose movement happened to conform to the current ictus of our common and continuous rhythm, whereupon, with a very brief, chorealike shiver, the interrupted gesture of one twin would be swallowed and dissolved in the enriched ripple of the other's completed action. I say "enriched" because the ghost of the unpicked flower somehow seemed to be also there, pulsating between the fingers that closed upon the fruit"

 

I consider both as exemplary of a particular consequence  of Nabokov's ingenious manipulation of words. To me it seems that he managed to find  -  and often apply -  the exact location from which a word  (not actually an entire sentence, nor a logical paradox) could potentialize its contradictory indications of meaning. 

A scissor that is used to cut and separate can also be cut and separated.

Two "I" conjoined by a xiphoid, membrane or an umbellical chord to constitute an "H", "forget" this linkage and see their separated  partner as another individual "I". 

One motion would simultaneously pluck a fig and carry in it the ghost of an unpicked flower that continues to live on in the fig*

(btw I'm deliberately avoiding freudian theories on castration aso).

 

My proposition: Very often when Nabokov asserts something his affirmation carries along the ghost of its opposite. The 1958 short-story reflects and describes, in part, this monstruous "doubleness" in words, ideas, life.

 

 

* - This "ghost", I've seen it outlined in Updike"s novel "Marry Me" ( the body of the rival present during coition by a certain concavity in the lover's reminiscing motions).

It is a constant feature of controversial engraver, sculptor and painter Hans Bellmer ( the feminine imprint of a nate in a sofa matching the next sitter's, a masculine seal of another actual nate,etc).

Hans Bellmer was fond of nymphets ( his cousin Ursula), palindromes ( one he collected by Victor Hugo is worth quoting here: “l’ame dês uns jamais n’use de mal”. ). He only recognized one of his twin daughters, aptly called Dorianna to honor Wilde's Dorian Gray.

( Cf.  R. C. Morgan. “Hans Bellmer: the Infestation of Éros”. A Hans Bellmer Miscellany Malmberg and T. Baum, 1993, pp. 7-9 ; Yves Bonnefoy, “La Corruption des Lois”, Obliques, 1979, p. 39.Hans Bellmer; Petite Anatomie de l‘Inconscient Physique ou l’Anatomie de l’Image, 1957, p. 38, Jean-François Rabain, “Le Sexe et Double” (1979). Obliques, Ed. Borderie, Nyons, p. 21.)