From the start of The Unnamable, as the unnamable watches Beckett’s fictional character Murphy pass by, we are tempted to call this relation between a narrator and his “vice-existers” a reflexivity; it’s the text’s self-awareness. Awareness and reflection, mirrors and knowledge, the classical terms of mise-en-abîme, may not be the best description of the unnamable’s dream of a semblable—subjective and objective genitive combine: the dream a semblable has; one’s dream about a semblable.

Late in The Unnamable, the unnamable is speculating that “they” might come to coax him out—out of where he is, out of his immobility, into their world. He can’t go and won’t go, but this refusal is passive. Should “they” come, they won’t find a stalwart resistant, holding out: “let them come and get me, they’ll find nothing, then they can depart, with an easy mind.” But they might not all show up at once; they might send only a representative (they have their “vice-existers” too, it seems):

“And if there is only one, like me”—if they send only one—“he too can leave without remorse, having done all he could, and even more, to achieve the impossible and so lost his life, or stay here with me, he might do that, and so be a like for me [ça me ferait un semblable], that would be lovely, my first like, that would be epoch-making [ça ferait date], to know I had a like [me savoir un semblable: to know myself a semblable], a congener, he wouldn’t have to be like me, he couldn’t but be like me [il n’aurait pas besoin de me ressembler, il me ressemblerait, forcément],"

Their vice-exister would not “be” a like for the unnamable, or not only: ça me ferait un semblable means both “that would make a like for me” and “that would make a like of me.” The translation, too, reverses something in the French, the unnamable’s knowledge: “to know I had a like” is me savoir un semblable: to know myself a semblable. Far from knowing he has a like, the unnamable knows himself a like. But this self-knowledge, too, is something other than the classical "know thyself." It's an unknowing, an unconscious, a dream: 

he’d dissappear, he’d know nothing either, there we’d be the two of us [there; having disappeared, they would be there], unbeknown to ourselves, unbeknown to each other [chacun à son insu, à l’insu l’un de l’autre], that’s a darling dream I’ve been having, a broth of a dream [c’est un beau rêve que je viens de faire là, un excellent rêve]. And it’s not over. [Et qui n’est pas fini.]

An involution: because the dream is not yet over, the dream the unnamable has been having (or the dream he has just now “made,” in the French text) now comprises the narration as well—narration of the dream, narration of the whole novel, the writing of all that the unnamable writes that he cannot lift his hand from his knee to write, all this is folded into the dream. We could call this reflexivity, a self-aware text, but the figure the unnamable brings before us is not that of knowing: “each to his unknowing” [my own translation of chacun à son insu], unbeknown, the one to the other [à l’insu l’un de l’autre].