Jung was the first modern psychologist to have an inkling of the nature of echoes. In his studies, he called them "archetypes" and said they populated the "collective unconscious." By the time I started taking psychoactives, his terminology was firmly rooted in that self-same linguistic landscape (a self-referential echo, if you will), and popular consciousness (though, there is very little that is "conscious" about memetic propagation) was very infatuated with these concepts (and, even more so, of the "possibilities" offered by them). No one bothers to footnote a discussion of "Jung's collective unconscious" with the fact that, by the end of his life, he had abandoned the term.
There are two types of dreams. You can certainly find a number of organization schemata by which to code dreams, but they are simply finer gradations of a basic duality: the Enhypnia and the Oneiroi. We draw these definitions from Artemidorus' Oneirocritica. The Enhypnia is a dream of a basal nature: one born of the passions and inflammations of the flesh and lower mind, one that reflects the dreamer's current state of mind and body. The Oneiroi is a divinely inspired message, a communication with sacred beings that the mind translates as a series of coded symbols.
At the risk of oversimplification, the distinction boils down to an "unenlightened" source and a "illuminated" one. The primal dream is simple to parse: we dream of food when we go to bed hungry; we fantasize about people we have seen or touched; we fret and twist and sweat when we are stalked by wild animals in our sleep. On the other hand, we do not understand the tongue of the gods, and our deformed and shrunken language centers try to render the music as abstract symbols. With varying results.
Yes, echoes. Do you know what you need to produce an echo? Something to make sound with, and something to hear it. If, in the beginning, there was nothing but Void, was God mute? Is the Logos—his first word, that Unutterable syllable—is it nothing more than a moan of terror? Was this cry, made so vast and huge that the Void split in twain, nothing more than a desperate attempt to find someone else in the darkness?
And, when God made the Shadow, did the Shadow not respond when God sounded his barbaric yawp across the emptiness of Heaven a second time?
What will happen the third time? Will the Shadow respond, or has it already? Has it already discovered its own voice? Has it learned how to further shape its twisted tongue? Babble on and on . . .
We are the echo of echoes, Harry. You asked me to remind you. When we were in the white room, where the black stones steam. You don't remember because you are facing the wrong way, but trust me.