In the early literature the inexpressibility of Brahman was expressed in the dead-end expression, a principal expression of Vedic insight, Tát [literally, ‘That’].
The Summum Bonum of popular, if redacted Dharmic Teaching is: Tát Tvam Asi, the same Tát [‘That’] of the Rig Veda. In translation: ‘That are’t Thou’.
‘That’ is an Expression of Inexpressibility. A self-scuttling assertion in negation, an immediate, unregenerate self-contradiction. It is neither noun nor verb, is grammatically homeless, a lexicographer’s nightmare, and meant to be so.
Even to call it ‘Inexpressible’ places it in counterpoint to the binary clutch of ‘Expressible’. And in that very act, violates its reference.
It includes all markers, any and every whiff of presumption to identity. Aspects, elements, endowments, features, qualities, temperament, tendencies. You may not source it for ethical or social directives [rules], go philosophical or poetic on its attributes…
Point a finger, draw a line, a thought, emote a feeling towards ‘That’ and by that very act, what you have pointed a finger to, drawn a line of, thought, emoted, is not ‘That’.
From the Diamond Sutra: ‘The Tathagata has no formulated teaching to enunciate. Wherefore? Because the Tathagata has said that truth is uncontainable and inexpressible.,,’
[‘Unformulated Principle‘? Formulation is the essence of Principle. Is that a Self-Negating Expression sneaking by?]
The literature of this period shows that Siddhartha Gautama’s formal schooling, that of a high-born Kshatriya Prince, was firmly in the classic Dharmic paradigm.
It was assigned to five established Dharmic teachers and a supporting crew of noted scholars. The first Upaniṣads would have been standard fare for every beleaguered student of his rank and of his day.
Siddhartha Gautama’s chosen name for himself was not as ‘The Buddha’ [a later appellation] but as the Tát-āgathā [literally, ‘That-Gone’] again, the same Tát [‘That’] of the Rig Veda.
A Tát-āgathā is one: ‘Entered in Tát’ [‘That’]. It says nothing about any ‘Object’ [such as an imagined ‘That’]. It is all about the Subject. Or rather, the absence of it.
From the Diamond Sutra: ‘If anyone should say that the Tathagatha comes or goes or sits or reclines, he fails to understand my teaching. Why? Because ‘Tathagata’ has neither whence nor whither, therefore is He called Tathagatha.’
In the highest tradition of the Buddha-Dharma one does not worship The Buddha, which is easy enough. The struggle is to become a Tat-āgatha.