Mandukya Karika, verse 2.11

Sanskrit text, IAST transliteration and English translation

उभयोरपि वैतथ्यं भेदानां स्थानयोर्यदि ।
क एतान्बुध्यते भेदान्को वै तेषां विकल्पकः ॥ ११ ॥

ubhayorapi vaitathyaṃ bhedānāṃ sthānayoryadi |
ka etānbudhyate bhedāṅko vai teṣāṃ vikalpakaḥ || 11 ||

11. If the objects cognized in both the conditions (of dream and of waking) be illusory, who cognizes all these (illusory objects) and who again imagines them?

Shankara Bhashya (commentary)

The opponent asks, “If the objects, cognized in the-waking and dream states, be devoid of reality, who¹ is the cognizer of these,—objects imagined by the mind, both inside (subjective), and outside (objective)? Who is, again, their fmaginer?” In short, what is the support (substratum) of memory and knowledge? If² you say none,. then we shall be led to the conclusion that there is nothing like Ātman or Self.

Anandagiri Tika (glossary)

¹ Who, etc.—It is the subject or the ego who, remembering his past experiences, has similar experiences in the present. We can infer a subject only from the facts of memory and experience. If experience and memory be unreal, the subject also would be unreal or non-existent.

² If, etc.—If the Self (Ātman) and the objective world be unreal, then all categories of experience, viz., knower, known and knowledge become mere illusion. That is the same as believing in absolute nihilism in which the existence of even Ātman or Self is denied. But this contention is invalid. One cannot deny the existence of Ātman. For. one who refutes Ātman (the knower) takes the position of Ātman. Therefore the theory of the non-existence of Ātman cannot be admitted.