Mandukya Karika, verse 2.3


अभावश्च रथादीनां श्रूयते न्यायपूर्वकम् ।
वैतथ्यं तेन वै प्राप्तं स्वप्न आहुः प्रकाशितम् ॥ ३ ॥

abhāvaśca rathādīnāṃ śrūyate nyāyapūrvakam |
vaitathyaṃ tena vai prāptaṃ svapna āhuḥ prakāśitam || 3 ||

3. Following reason, (as indicatea above) Śruti declares the non-existence of the chariots, etc. (perceived in dream). Therefore it is said (by the wise) that Śruti itself declares the illusoriness (of the dream-experiences), established (by reason).

Shankara Bhashya (commentary)

For this reason also the objects perceived to exist in dream are illusory. For, the absence of the chariots, etc. (perceived in dream) is stated by Śruti, in such passages as “There1 exists neither chariot, etc.” its assertion being based on reason.2 In the opinion of the wise, i.e., the knowers of Brahman, the illusoriness (of the dream objects) has been established on the ground of their being perceived within the contracted space in the body. The Śruīi only reiterates it in order to establish the self-luminosity3 (of Ātman) in dream.