In Through the Gates of the Silver Key, we are introduced to the idea that reality as perceived by mortals and lesser beings is nothing but a fragmentary, partial illusion that exists as an imperfect aspect of the true nature of the world, which is a changeless, static oneness devoid of any differentiations, that exists beyond all perspectives.
"Time, the waves went on, is motionless, and without beginning or end. That it has motion, and is the cause of change, is an illusion. Indeed, it is itself really an illusion, for except to the narrow sight of beings in limited dimensions there are no such things as past, present, and future. Men think of time only because of what they call change, yet that too is illusion. All that was, and is, and is to be, exists simultaneously.
These revelations came with a godlike solemnity which left Carter unable to doubt. Even though they lay almost beyond his comprehension, he felt that they must be true in the light of that final cosmic reality which belies all local perspectives and narrow partial views; and he was familiar enough with profound speculations to be free from the bondage of local and partial conceptions. Had his whole quest not been based upon a faith in the unreality of the local and partial?
After an impressive pause the waves continued, saying that what the denizens of few-dimensioned zones call change is merely a function of their consciousness, which views the external world from various cosmic angles. As the shapes produced by the cutting of a cone seem to vary with the angles of cutting—being circle, ellipse, parabola, or hyperbola according to that angle, yet without any change in the cone itself—so do the local aspects of an unchanged and endless reality seem to change with the cosmic angle of regarding. To this variety of angles of consciousness the feeble beings of the inner worlds are slaves, since with rare exceptions they cannot learn to control them. Only a few students of forbidden things have gained inklings of this control, and have thereby conquered time and change. But the entities outside the Gates command all angles, and view the myriad parts of the cosmos in terms of fragmentary, change-involving perspective, or of the changeless totality beyond perspective, in accordance with their will."
The inhabitants of this ultimate reality are the true selves The Outer Gods known as The Archetypes, eternal, unchanging and uncreated entities who participate in this totality beyond all divisions, and hold all lesser entities as nothing but facets of themselves.
"All descended lines of beings of the finite dimensions, continued the waves, and all stages of growth in each one of these beings, are merely manifestations of one archetypal and eternal being in the space outside dimensions. Each local being—son, father, grandfather, and so on—and each stage of individual being—infant, child, boy, young man, old man—is merely one of the infinite phases of that same archetypal and eternal being, caused by a variation in the angle of the consciousness-plane which cuts it. Randolph Carter at all ages; Randolph Carter and all his ancestors both human and pre-human, terrestrial and pre-terrestrial; all these were only phases of one ultimate, eternal "Carter" outside space and time—phantom projections differentiated only by the angle at which the plane of consciousness happened to cut the eternal archetype in each case.
...
The archetypes, throbbed the waves, are the people of the ultimate abyss—formless, ineffable, and guessed at only by rare dreamers on the low-dimensioned worlds. Chief among such was this informing BEING itself . . . which indeed was Carter's own archetype. The glutless zeal of Carter and all his forbears for forbidden cosmic secrets was a natural result of derivation from the SUPREME ARCHETYPE. On every world all great wizards, all great thinkers, all great artists, are facets of IT."