Dreams are brought forth by the longing of the manas

Answer: In the middle of the night, with the air conditioner on and the body very cold while asleep, if 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 cover itself with a blanket or turn off the air conditioner. In order to resolve this, it therefore produces a dream about the body feeling cold, in which the mind consciousness feels the body to be very cold, shivering in the world of ice and snow.

If the mind consciousness is rather clever and quick, it will wake up; after waking, it knows the body really is very cold, then observes why it is cold, realizes that the air conditioner is on, and so turns it off and covers up with the blanket. Once the matter is handled, it 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 being frozen. This matter demonstrates that the manas can know many dharmas, but without the six consciousnesses as assistants to help it carry out its activities, it is powerless and has no way to 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 activity manifests in many ways: it manifests in dreams, in the bodily, verbal, and mental actions it undertakes, in all kinds of mental activities, in emotions, in the body's subconscious reactions, and in the body's involuntary reactions. The manas, together with the tathāgatagarbha, 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 run normally, but the six consciousnesses do not appear—they are too weak, and there is no way to set the five aggregates in motion. The manas's anxious sense of powerlessness is something ordinary people generally cannot perceive; even if they are aware of it, they mistakenly take it to be the anxiety and powerlessness of the mind consciousness. Their thinking and cognition can only remain at the level of the mind consciousness, following the mind consciousness's lead, unable to probe further into the deep psychological layers of the manas that lies behind the mind consciousness.