buddher jagaranam svapnah
susuptir iti vrttayah
so ’dhyaksah purusah parah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Intelligence can be perceived in three states of activity — wakefulness, dreaming and deep sleep. The person who perceives these three is to be considered the original master, the ruler, the Supreme Personality of Godhead.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Without intelligence one cannot understand the direct activities of the senses, nor can he understand dreaming or the cessation of all gross and subtle activities. The seer and controller is the Supreme Personality of Godhead, the Supreme Soul, by whose direction the individual soul can understand when he is awake, when he is sleeping, and when he is completely in trance. In Bhagavad-gita (15.15) the Lord says, sarvasya caham hrdi sannivisto mattah smrtir jñanam apohanam ca: “I am seated in everyone’s heart, and from Me come remembrance, knowledge and forgetfulness.” The living entities are completely absorbed in the three states of wakefulness, dreaming and deep sleep through their intelligence. This intelligence is supplied by the Supreme Personality of Godhead, who accompanies the individual soul as a friend. Srila Madhvacarya says that the living entity is sometimes described as sattva-buddhi when his intelligence acts directly to perceive pains and pleasures above activities. There is a dreaming state in which understanding comes from the Supreme Personality of Godhead (mattah smrtir jñanam apohanam ca). The Supreme Personality of Godhead, the Supersoul, is the supreme controller, and under His direction the living entities are subcontrollers. One must understand the Supreme Personality of Godhead with one’s intelligence.