Brahman is the ancestor, Tát [literally, ‘That’] the grandfather and Tát-āgathā [‘Entered in Tát’] the father of Shūnyam.
From the Diamond Sutra: ‘Moreover, the Tathagata has no formulated teaching to enunciate. Wherefore? Because the Tathagata has said that truth is uncontainable and inexpressible. It neither is nor is it not. Thus it is that this unformulated Principle is the foundation of the different systems of all the sages.‘
[‘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 Hindu 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’] or in its more literal and ambiguous translation: ‘That-Gone’ [also as ‘That-Come’]. 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.’