Un dessein si funeste, S'il n'est digne d'Atrée, est digne de Thyeste

It is because of the virtual character of the big Other that, as Lacan put it at the very end of his "Seminar on the Purloined Letter," a letter always arrives at its destination. One can even say that the only letter which fully and effectively arrives at its destination is the unsent letter - its true addressee are not flesh-and-blood others, but the big Other itself:

The preservation of the unsent letter is its arresting feature. Neither the writing nor the sending is remarkable (we often make drafts of letters and discard them), but the gesture of keeping the message when we have no intention of sending it. By saving the letter, we are in some sense 'sending' it after all. We are not relinquishing our idea or dismissing it as foolish or unworthy (as we do when we tear up a letter); on the contrary, we are giving it an extra vote of confidence. We are, in effect, saying that our idea is too precious to be entrusted to the gaze of the actual addressee, who may not grasp its worth, so we 'send' it to his equivalent in fantasy, on whom we can absolutely count for an understanding and appreciative reading. [2]

Is it not exactly the same with the symptom in the Freudian sense of the term? According to Freud, when I develop a symptom, I produce a ciphered message about my innermost secrets, my unconscious desires and traumas. The symptom's addressee is not another real human being: before an analyst deciphers my symptom, there is no one who can read its message. Who, then, is the symptom's addressee? The only remaining candidate is the virtual big Other. This virtual character of the big Other means that the symbolic order is not a kind of spiritual substance existing independently of individuals, but something that is sustained by their continuous activity. However, the provenance of the big Other is still unclear. How is it that, when individuals exchange symbols, they do not simply interact with each other, but always also refer to the virtual big Other? When I talk about other people's opinions, it is never only a matter of what me, you, or other individuals think, but also a matter of what the impersonal "one" thinks. When I violate a certain rule of decency, I never simply do something that the majority of others do not do - I do what "one" doesn't do.

- Slavoj Zizek, "How to Read Lacan"

"A letter always arrives at its destination since its destination is wherever it arrives." Its underlying mechanism was elaborated by Pêcheux apropos of jokes of the type: "Daddy was born in Manchester, Mummy in Bristol, and I in London: strange that the three of us should have met! In short, if we look at the process backwards, from its contingent result, the fact that events took precisely this turn could not but appear as uncanny, concealing some fateful meaning — as if some mysterious hand took care that the letter arrived at its destination, i.e., that my father and my mother met....