Why Do We Not Know We Are Dreaming While Dreaming?

In a dream, who is the one that knows it is a dream? When awake, who is the one that knows sense objects? Both within and outside the dream, the sixth and seventh consciousnesses both have knowing; the knowing of all dharmas is primarily based on the knowing of the sixth and seventh consciousnesses. The five sense consciousnesses can only know the five sense-object realms in reality, and cannot know dream realms, because there are no five sense-object realms in a dream. The knowing nature of the mind consciousness is greatly related to the physical body; when the physical body has obstructions, the knowing of the mind consciousness becomes weak or ceases. For a person who has attained the four dhyānas and eight samādhis, the physical body has no obstructions, and the knowing of the mind consciousness is clear and vast; whether asleep or not, one can know with great clarity, and no matter how many bottles of wine one drinks, one will not become drunk, because the wine can no longer numb the central nervous system of the brain, and thus the mind consciousness is unaffected.

The knowing of the mind consciousness is also greatly related to the knowing of the manas. Generally speaking, the manas knows all dharmas, except that the question of whether it knows them as they truly are is involved. As for the portion that the manas can know as it truly is, how it can influence the mind consciousness so that the mind consciousness also knows, and promptly processes what is known, involves the ability of communication between the two consciousnesses. So-called communication ability is wisdom; how what the mind consciousness knows can effectively influence and guide the manas also involves communication ability, that is, how the wisdom is. Wisdom is also closely related to meditative concentration (samādhi); meditative concentration can make the mind quiet, peaceful, and steady, enhance the capacity for contemplation, and make the power of wisdom great, so that the mutual influence between the two consciousnesses becomes great. Meditative concentration can also make the physical body unobstructed; when the physical body is unobstructed, the mind consciousness has no hindrance, its knowing is keen and unimpeded, and it can effectively influence the manas. Conversely, the manas can also effectively influence the mind consciousness; the two exchange what they have, and knowing all dharmas becomes smooth and with little hindrance.

Being the same in waking and dreaming is a wisdom realm cultivated through practice; knowing that it is a dream and not being trapped by the dream realm is wisdom. This practice mainly refers to the practice of meditative concentration; meditative concentration is an indispensable link in practice—only with meditative concentration can wisdom be developed, making the knowing of the sixth and seventh consciousnesses more truthful and more in accord with principle, knowing more truly, more subtly, and more vastly. And only by removing the hindrance of sleep can deep meditative concentration arise. For a person with deeper meditative concentration, thinking is clear when awake, and one is also not deluded in dreams; just as when awake, one knows realms without obstruction.

The knowing of ordinary people has obstructions—that is what is colloquially called lacking supernatural powers—whereas the knowing of a person with supernatural powers is unobstructed, having the ability to know others' minds, the divine eye, and so on; this is the karmic retribution of the merit of concentration and wisdom. Knowing one is dreaming within a dream is the retribution attained by a person whose meditative concentration is excellent and whose mind has become pure. Ji Gong the monk had the four dhyānas and eight samādhis and had supernatural powers; no matter how much wine he drank, his nervous system would not be affected or anesthetized; his mind consciousness was always awake and could observe and know all realms as they truly are. When ordinary people fall asleep, the mind consciousness ceases, and the portion of the manas's function of knowing realms that relies on the mind consciousness no longer operates; therefore, when dreaming, the manas's power of discrimination is weak and it does not know it is a dream, and the solitary consciousness (mano-vijñāna-eka-citta) in the dream also has very weak discriminating power and likewise does not know it is a dream. But a person with cultivation, whose power of meditative concentration is strong, whose physical body is unobstructed, and whose sixth and seventh consciousnesses are clear, has strong discriminating power; while dreaming, one knows it is a dream and is not deluded.

Master Kuiji had the four dhyānas and eight samādhis and had supernatural powers; when sleeping at night he was extremely clear, even clearer than ordinary people when awake; his sixth and seventh consciousnesses were keen—after falling asleep, when a louse's leg fell off and it cried out in pain, Master Kuiji could hear it; this is the merit of the power of meditative concentration and the power of supernatural powers. Being able to hear the louse's cry while asleep—does this not show that he was not actually asleep? For ordinary people, sleep is a covering that can obscure their minds so they neither see nor hear, like a dead person. But for a person who has eliminated the covering of sleep, very little sleep is enough to nourish the physical body; meditative concentration will reach the first dhyāna or above, the mind is clear, the obstructions are slight, or there are no obstructions at all; during sleep the mind consciousness is not necessarily completely extinguished, yet the sleep is also sufficient—this differs from ordinary people.

Especially for a person with supernatural powers, their sleep is like being awake, even clearer than ordinary people when awake. In ancient times, people with martial arts skills also slept lightly and had high alertness; this alertness can be said to belong to the mind consciousness, but the manas indeed also has alertness, and its alertness is even stronger in function and effect than that of the mind consciousness; therefore, without the manas, the functions and effects of the mind consciousness cannot be fully explained. Sleep and torpor are of the same category, both belonging to hindrances and coverings, which can obscure the light of the conscious mind; only after the hindrance and covering of sleep is eliminated will the first dhyāna concentration appear. The more torpid one is while sleeping, the poorer one's meditative concentration is, or one has no meditative concentration and heavy coverings; the more deluded one is in dreams, the less meditative concentration one has; the more easily one becomes drunk on alcohol, the greater the obstruction of the physical body and the less meditative concentration one has. Those with deep meditative concentration can regulate the physical body well, be unaffected by environmental factors, and not obstruct the functioning of the six consciousnesses. Therefore, the power of concentration is extremely important; even if one does not study Buddhism or cultivate, if meditative concentration is well cultivated, the benefits are also very great.