The idea that our inner world contains or represents the outer world in miniature; that each individual human being embodies in small the whole of the universe; that, in the words of Pico della Mirandola (quoted by Barfield in RCA 237), "Whereas God contains in Him all things, because He is their source, Man contains in him all things, because he is their centre"--belief in the existence of the Macrocosm and the Microcosm--is an ancient one, shared by East and West alike.1 Barfield's own version of it is drawn from a number of sources, including the thought of Samuel Taylor Coleridge,2  and the teachings of Rudolf Steiner.3

In "The Time-Philosophy of Rudolf Steiner" we are told that "The human microcosm [is] a centre, into which irradiated centripetally an unbroken influence from the macrocosm" (RCA 187). And we learn from the Meggid in Unancestral Voice that macrocosm/microcosm is a "once and future" idea. "The truth," the Meggid explains, "that the human body is an epitome of nature was once known to the generality of mankind, and though it has long been lost to their view, they will find the truth again. . . ."

    "If you would faithfully trace the course taken by the mind of man since it first began to apprehend regularity in nature, then you must distinguish, in the domain of nature herself, between the earth and the universe beyond it. It was in the universe beyond, among the stars and planets, that regularity and irregularity were first distinguished. It was not until men had transferred the habit of that discernment from the heavens to the earth that they beheld, upon earth too, any "laws" of nature. And this they could do, because it is out of that universe that the body of the earth has shrunk together. It has shrunk together and gathered into itself the life of the universe, as the seed shrinks together within the parent plant. All its exterior irregularities point back to that origin. But the earth is not a lifeless relic; it is also the living body of mankind, and, permeating an old machine, there is the new life that looks forward to the future." (154)
See in particular "The Time Philosophy of Rudolf Steiner" (RCA 184-204); Unancestral Voice, passim.
1In the East, for example, Hindu teaching holds that the individual self, Atman, is identical to Brahman, the divine being. In the west, Empedocles, Plato, Aristotle, the Stoics-all proffered some version of the macrocosm/microcosm idea, as have later thinkers like Meister Eckhart, Nicolas of Cusa, Bruno, Leibniz, Emerson, and Whitehead. (See DPR 324.)
2In What Coleridge Thought, Barfield quotes (with obvious admiration) Coleridge from his Theory of Life on macrocosm/mircrocosm:
    Man possesses the most perfect osseous structure, the least and most insignificant covering. The whole force of organic power has attained an inward and centripetal direction. He has the whole world in counterpoint to him, but he contains an entire world within himself. Now, for the first time at the apex of the living pyramid, it is Man and Nature, but man himself is a syllepsis, a compendium of Nature--the Microcosm! Naked and helpless cometh man into the world. Such has been the complaint from earliest time; but we complain of our chief privilege, our ornament, and the connate mark of our sovereignty. (68)
3Theodor Schwenk's Sensitive Chaos: The Creation of Flowing Forms in Water and Air presents a fascinating application of Steiner's version of macrocosm/microsm in its demonstration of the way the same natural forces that shape the creation of our inner world-the convolutions of the brain for example-also function geologically-in, for example, the flow of a river or the patterning of cloud movements.