Dreams are brought forth by the longing of the manas

Question: In summer, after falling asleep with the air conditioner on, one sometimes dreams of walking in a world of ice and snow, feeling cold all over. From the perspective of Yogācāra, what is going on here?

Answer: When you fall asleep at night with the air conditioner on and your body becomes very cold, but there are no six consciousnesses to perceive the cold, the problem of the body being cold cannot be solved. The manas does not sleep; although it knows the body is cold, it has no way to deal with the matter—it cannot pull up a blanket for itself or turn off the air conditioner. In order to resolve this, it produces a dream about the body being cold, in which the mind consciousness feels that the body is very cold, shivering in a world of ice and snow.

If the mind consciousness is rather clever and quick-witted, it will wake up; after waking, it knows that the body really is very cold, then observes why it is cold, realizes that the air conditioner is on, and so turns it off, pulls up the blanket, finishes handling the matter, and goes back to sleep. If the mind consciousness is less alert, it will continue to endure the cold until waking at daybreak, and may even catch a cold from the chill. This matter demonstrates that the manas can know many dharmas, but without the six consciousnesses as assistants to help it carry out its tasks, it is powerless and cannot run the activities of the five aggregates. The six consciousnesses serve the manas, work for the manas, and fulfill the manas' needs.

Dreams are all conjured up by the manas's longing. The manas's mental activities manifest in many ways: in dreams, in the bodily, verbal, and mental actions it undertakes, in all sorts of mental activities, in emotions, in the body's subconscious reactions, and in the body's involuntary reactions. Together with the tathāgatagarbha, the manas controls and regulates the physical body and the five aggregates; the moment the manas's mind stirs, the body moves and the five aggregates begin to operate.

What ordinary people observe are only the surface phenomena of the six consciousnesses, or they classify the mental activities of the manas under the mind consciousness as well, unable to distinguish the mental activities of the manas from those of the mind consciousness. When the mind consciousness disappears or becomes weak and feeble, the manas very much wants the five aggregates to be active and to function normally, but the six consciousnesses do not appear—they are too weak to make the five aggregates run. That anxious, powerless feeling of the manas is something ordinary people cannot perceive; even if they are aware of it, they mistake it for the anxiety and powerlessness of the mind consciousness. Their thinking and understanding can only remain at the level of the mind consciousness, following its lead, unable to probe further into the deep psychological layers of the manas that lies behind the mind consciousness.