On Mundaka Upanishad: Vast, unthinkable, subtler than the subtle, farther than farness itself

Following is an excerpt from a samvaad (dialogue) session with Acharya Prashant.

बृहच्च तद्दिव्यमचिन्त्यरूपं सूक्ष्माच्च तत्सूक्ष्मतरं विभाति ।
दूरात्सुदूरे तदिहान्तिके च पश्यन्त्विहैव निहितं गुहायाम् ॥

bṛhacca taddivyamacintyarūpaṃ sūkṣmācca tatsūkṣmataraṃ vibhāti
dūrātsudūre tadihāntike ca paśyantvihaiva nihitaṃ guhāyām

Vast is That, divine, its form unthinkable; it shines out subtler than the subtle: very far and farther than farness, it is here close to us, for those who have vision it is even here in this world; it is here, hidden in the secret heart.

~ Verse 3.1.7

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Acharya Prashant (AP): “Vast is That, divine, its form unthinkable; it shines out subtler than the subtle: very far and farther than farness, it is here close to us, for those who have vision it is even here in this world; it is here, hidden in the secret heart.”

Basics. To whom are these words addressed? They are addressed to the questioning mind that is restless, answerless, and peaceless for some reason. And the questioning mind has a nature of its own.

Now, see what these words mean in the context of the nature of the mind. The sage tells the mind, the ego, the seeker, the student: “Vast is That.” Now, what does vastness imply here?

In the limited sense of the mind, in the usual context of conversation, vastness means a great degree of space, right? That’s how the mind is habituated to comprehending vastness. But here, the entire conversation is taking place on some other plane. This is not the vastness that the mind is accustomed to; the Rishi is not referring to the vastness within the mind.

You see, when you say there is a vastness within the mind, first of all, what is it you are positing about the mind? If I say there is a vast space…