Studying the first fundamental proposition in The Secret Doctrine, we see that the “Omnipresent, Eternal, Boundless, and Immutable PRINCIPLE” postulated in SD I, 14 is the Rootless Root of “all that was, is, or ever shall be”, Parabrahman, the Absolute.
Two aspects of the Absolute are then described, which are absolute abstract Space and absolute abstract Motion, the latter symbolized in the Book of Dzyan as The Great Breath.
The Great Breath is seen by HPB as precosmic Ideation, while the other aspect of the Absolute is seen as precosmic root-substance (Mūlaprakṛti). Both these are underlying manifested Consciousness and manifested Matter respectively, or Spirit and Matter, Subjectivity and Objectivity in the manifested universe.
These two aspects are obviously referred to in the last sentence of the passage, after the summary, “The ONE REALITY; its dual aspects in the conditioned Universe.”
Mūlaprakṛti: the Veil over Parabrahman
In this context HPB refers to ‘Mr. Subba Row’s four able lectures on the Bhagavad Gita, “Theosophist,” February, 1887.’
In the first of these lectures, on page 304 of The Theosophist Vol. VIII, we find some explanation about the relationship between Parabrahman and Mūlaprakṛti:
From its objective standpoint, Parabrahman appears to it as Mulaprakriti.
The “it” in this sentence is the ego “having an objective consciousness of its own”.
Parabrahman is an unconditioned and absolute reality, and Mulaprakriti is a sort of veil thrown over it. Parabrahman cannot be seen as it is.
What is said here, is that Parabrahman is the Absolute, and Mūlaprakṛti is an aspect of it, only in the sense that we cannot see more of it than that. Mūlaprakṛti is not a component, “aspect” or principle in itself, either separate from or united with Parabrahman. This is different from HPB’s interpretation in her description of the first fundamental principle, as two aspects, pre-Cosmic Ideation and pre-Cosmic Substance.
On page 305 of The Theosophist Vol. VIII, “the highest Trinity that we are capable of understanding” is mentioned, being Mūlaprakṛti, Īśvara (the Logos) and the “conscious energy of he Logos” (i.e. HPB’s fohat). This is the trinity we have defined as the First, Second and Third Logos. (see The Three Logoi)
In SD I, 14 we find:
Thus, then, the first fundamental axiom of the Secret Doctrine is this metaphysical ONE ABSOLUTE — BE-NESS — symbolised by finite intelligence as the theological Trinity.
On page 305, Subba Row describes the “conscious energy of he Logos” as the “Holy Ghost of the Christians”. This confirms that Subba Row thought of this trinity as the “theological Trinity”.
Although HBP does not give any indication which trinity she is referring to, from these correspondences between her description and Subba Row’s, we can assume that she refers to the Trinity that we have defined as the First, Second and Third Logos, which she sees as “symbolising” the “metaphysical ONE ABSOLUTE — BE-NESS”, which is the “Omnipresent, Eternal, Boundless, and Immutable PRINCIPLE” postulated in SD I, 14.
This same problem appears in SD I, 15:
Considering this metaphysical triad as the Root from which proceeds all manifestation, [...]
“This” seems to refer to:
Spirit (or Consciousness) and Matter are, however, to be regarded, not as independent realities, but as the two facets or aspects of the Absolute (Parabrahm), [...]
Again the only possible interpretation here seems the Absolute itself, together with its two aspects. A more fitting interpretation would be though, that the Root is the Parabrahman which she sees as a “metaphysical triad” in itself, or the triad “symbolising” Parabrahman.