Mandukya Karika, verse 4.39

Sanskrit text, IAST transliteration and English translation

असज्जागरिते दृष्ट्वा स्वप्ने पश्यति तन्मयः ।
असत्स्वप्नेऽपि दृष्ट्वा च प्रतिबुद्धौ न पश्यति ॥ ३९ ॥

asajjāgarite dṛṣṭvā svapne paśyati tanmayaḥ |
asatsvapne'pi dṛṣṭvā ca pratibuddhau na paśyati || 39 ||

39. Being deeply impressed with the (reality of the) unreal objects which a man sees in the waking state, he sees those very things in dream as well. Moreover the unreal objects cognised in the dream are not seen again in the waking state.

Shankara Bhashya (commentary)

(Objection)—It is you who stated that the dream is the effect of the waking experience. That being the case, how do you refute causality?

(Reply)—Listen to our explanation of the causality, referred to in that instance. One perceives in the waking state objects which are unreal like the snake imagined in the rope. Being deeply impressed by such (illusory) perception, he imagines in the dream, as in the waking; state, the subject-object relationship and thereby perceives (dream) objects. But though full of the unreal seen in the dream, he does¹ not see those (unreal) objects, over again, in the waking state. The reason is the absence of the imaginary subject-object relationship (one experiences in dream). The word “cha,” “moreover” in the text denotes that the causal relationship between the waking and the dream states is not always observed. Similarly,² things seen in the waking state are not, sometimes, cognised in dream. Therefore the statement that the waking condition is the cause of the dream is³ not made from the standpoint of the Ultimate Reality.

Anandagiri Tika (glossary)

¹ Does not, etc.—This shows that the causal relation is not seen between the waking and the dream states.

² Similarly, etc.—This is another reason to show that the causal relation does not exist between the waking and the dream states.

³ Is not made, etc.—Waking state is said to be the cause of the dream only from the empirical standpoint.

From the subsequent waking standpoint we call the antecedent, dream state unreal. But we do not find a causal relation between the antecedent dream state and the subsequent waking one because we view it from the waking standpoint—when the dream is over. Objects seen in dream could have been seen even now in the waking state if the waking state were a part or continuation of the previous dream state.