Non-duality is not oneness

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

यस्मिन्सर्वाणि भूतान्यात्मैवाभूद्विजानतः।
तत्र को मोहः कः शोक एकत्वमनुपश्यतः ॥ ७ ॥

yasminsarvāṇi bhūtānyātmaivābhūdvijānataḥ |
tatra ko mohaḥ kaḥ śoka ekatvamanupaśyataḥ || 7 ||

When to the man of realization all beings become the very Self, then what delusion and what sorrow can there be for that seer of oneness? (Or — In the Self, of the man of realization, in which all beings become the Self, what delusion and what sorrow can remain for that seer of oneness?)
-Ishavasya Upanishad

Acharya Prashant: To begin with oneness in the absolute sense cannot be seen. Remember here, as we have said multiple times tonight, that the objective of the verses is to educate the mind. So, when the word ‘oneness’ is being used, it is being used in a sense that will be beneficial to the mind.

The mind cannot experience absolute oneness because the mind operates in duality. All experience requires the experienced object to carry a background of its opposite. On a white wall, you will perceive nothing if it is marked with white. You cannot write with a white marker on a whiteboard.

Experience necessitates two, for one to be perceived, the second has to keep lurking in the background. Absolute oneness means the object of perception, and its background, and the perceiver, have all become one. Now how can there be any experience?

So absolute oneness is not being talked of when the verse is saying, “How can there be delusion or grieve when he sees oneness?”

Then which oneness is being referred to here? At the level of the constitution of mind, at the level of the outer body of the mind as well as the inner body, the gross and the subtle bodies, that’s where we all are one. That’s the oneness being referred to, Ekatva.

Truth is not Ekatva, Truth is Advaita. There is a great difference. Oneness means…