‘Brahman is all of which the Upaniṣads speak‘ begins the celebrated Kena Upanishad.
Vedic Truth is irreducibly, ridiculously simple. There is Brahman. There is only Brahman. There is nothing else here.
It is also an extraordinarily dangerous claim in untrained hands. It may be talked about only in the light of True-Nothing, in the understanding arisen from alighting on Śūnyam.
The Symbol ‘0’ took birth, found formulation, as a direct result of the many attempts to understand what this word Brahman meant.
Brahman is from the root ‘Brh‘: ‘To Uphold, Support’. Brahman is: ‘That which upholds’, and was originally a Mantric expression for Yagnic formalities.
So what is this Brahman? What’s been told about it in the primary texts?
The earliest Mahāvākyam, a summary affirmation of primal Vedic Truth, is from the Chāndogya Upaniṣad (3.14.1, among others; around 1,000 BCE):
Sarvam Khalvidam Brahma: ‘All [this] is Brahman‘.
This is reflected in an early interpretation of the Symbol ‘0’ as Pūjyam, a mystical expression marking: ‘That worthy of worship’.
It was a simultaneous reference to both a Completeness [the Plenum of the Iśopaniṣad] and one of Absence.
OK. Now for the tricky part. If you miss this Loop, you miss Brahman.
What is Brahman? I don’t know. In fact I can never know what Brahman is. And why not? Because I am part of this ‘All’, whatever this ‘All’ is. Else it wouldn’t be the ‘All’.
The word Brahman is ensconced in layers of self-reference. It will twirl you around like a top if you don’t stay alert.
I can’t locate ‘The All’ while sitting on my rocker because ‘The All’ includes me sitting on my rocker. And it includes me thinking about locating ‘The All’ while sitting on my rocker. And…ad infinitum.
If you don’t see that, you will reduce Brahman to another Man-Made ‘God’. Which is pretty much the state of things today.