Theosophy Basics: Body, Soul, Spirit

Theosophy is known for its emphasis on seven principles; however, this concept can be simplified into a threefold division, often described as body, soul, and spirit. The interesting passage below gives a very theosophical description of this, with the holistic microcosm-macrocosm correspondence and, distinctive to Theosophy, a more modern-sounding scientific concept of spiritual evolution which correlates the Pythagorean Monad with an evolving soul, considered in atomic terms, with a traditional spiritual teleology. Note it is perhaps better not to consider the Paracelsian Three Spirits as identical with the Proclean Intelligible Triad, although of course they are related, the latter Triad corresponding to the later notion of the Triple Logos :

"Three spirits live and actuate man," teaches Paracelsus; "three worlds pour their beams upon him; but all three only as the image and echo of one and the same all-constructing and uniting principle of production.
The first is the spirit of the elements (terrestrial body and vital force in its brute condition);
the second, the spirit of the stars (sidereal or astral body — the soul);
the third is the Divine spirit (Augoeides)."

Our human body, being possessed of "primeval earth-stuff," as Paracelsus calls it, we may readily accept the tendency of modern scientific research "to regard the processes of both animal and vegetable life as simply physical and chemical."
This theory only the more corroborates the assertions of old philosophers and the Mosaic Bible, that from the dust of the ground our bodies were made, and to dust they will return. But we must remember that
" 'Dust thou art, to dust returnest,'
Was not spoken of the soul."

Man is a little world — a microcosm inside the great universe. Like a foetus, he is suspended, by all his three spirits, in the matrix of the macrocosmos;
and while his terrestrial body is in constant sympathy with its parent earth,
his astral soul lives in unison with the sidereal anima mundi. He is in it, as it is in him, for the world-pervading element fills all space, and is space itself, only shoreless and infinite.
As to his third spirit, the divine, what is it but an infinitesimal ray, one of the countless radiations proceeding directly from the Highest Cause — the Spiritual Light of the World?

This is the trinity of organic and inorganic nature — the spiritual and the physical, which are three in one, and of which Proclus says that
"The first monad is the Eternal God;
 the second, eternity;
the third, the paradigm, or pattern of the universe";
 the three constituting the Intelligible Triad.

Everything in this visible universe is the outflow of this Triad, and a microcosmic triad itself.
And thus they move in majestic procession in the fields of eternity, around the spiritual sun, as in the heliocentric system the celestial bodies move round the visible suns. The Pythagorean Monad, which lives "in solitude and darkness," may remain on this earth forever invisible, impalpable, and undemonstrated by experimental science. Still the whole universe will be gravitating around it, as it did from the "beginning of time," and with every second, man and atom approach nearer to that solemn moment in the eternity, when the Invisible Presence will become clear to their spiritual sight.

When every particle of matter, even the most sublimated, has been cast off from the last shape that forms the ultimate link of that chain of double evolution which, throughout millions of ages and successive transformations, has pushed the entity onward; and when it shall find itself reclothed in that primordial essence, identical with that of its Creator, then this once impalpable organic atom will have run its race, and the sons of God will once more "shout for joy" at the return of the pilgrim.
(Isis Unveiled, Vol. I, pp. 212-13)