The concept of the unity of Brahman was further examined and developed by Upanishadic seers. Brahman was both transcendental and immanent. Brahman was both physical and spiritual. Brahman was both phenomenal ( capable of being discerned through senses) and noumenal ( capable of being only intuited and not perceived by the senses). Brahman was therefore a conglomerate of the physical world and the non-physical or spiritual reality.

The Upanishads however make a distinction between the two, calling the physical as the lower aspect of Brahman and the spiritual the higher aspect. While the physical could be discerned through the senses, the noumenal was beyond descriptions or characteristics and the only attempt at defining it had produced the aphorism Neti, Neti or ”not this not that”.

Thus in  the Maitri Upanishad it is stated:

” There are assuredly two forms of Brahman: Time and the  Timeless. that which is prior to the Sun is the Timeless, without parts. But that which begins with the Sun is Time, which has parts.”

The two forms of Brahman envisaged were the formed and the unformed, the mortal and the immortal, the stationary and the moving, the actual and the Real.

The logic of Upanishadic Monism however encountered a serious problem in explaining the diversity of the manifold universe. How was this abundant diversity to be reconciled with the unshakable and uncompromising faith in an absolute unity, which was the fundamental characteristic of Brahman? Furthermore the idea of two aspects of Brahman also inclined towards a Dualism.

Thus as a corrective evolved the doctrine of Illusion or Maya, which then became a permanent feature of all Hindu thinking to the present times. The so called lower aspect of Brahman, the physical universe was declared to be a mirage, an illusion because the Upanishads had always held that ” there is only one Brahman, without a second.” The thought was then developed that Reality was indeed One and the diversity was an appearance arising from the ‘ignorance’ of the perceiver. Thus it is finally pronounced in the Maitri Upanishad:

”There are, assuredly, two aspects of Brahman; the formed and the formless. Now that which is the formed is unreal; that which is the formless is Real.”

Again in the Svetashvatar Upanishad the first word on the Maya doctrine is pronounced:

” This whole world, the illusion-maker projects….and in it by illusion the other is confined,

Now one should know that Nature is illusion and the Mighty Lord is the illusion-maker”

We then find that Brahman on the one hand, in its lower aspect becomes an illusion and in its higher aspect as unknowable  ( Neti, Neti)  The path to an appreciation of the concept of Brahman through realism had thus arrived at a frustrating impasse for seekers. those who had wished to immerse themselves in contemplating Brahman were left dissatisfied and confused in advancing any further on their metaphysical quest.

How the Upanishadic sages overcame this outcome and how the concept of Atman came to the rescue, putting the train back on the track,  we shall study in the next post.