The mind consciousness and the manas simultaneously discern and give rise to thoughts

In the process of discerning all dharmas—whether a thought arises or not, whether the thought is obvious or not, whether in the state of initial application (vitarka) or in the state of sustained examination (vicāra)—there is the discernment of the mind consciousness as well as the discernment of the manas. As long as a dharma has been discerned, these two consciousnesses are definitely present simultaneously. The difference lies in which one discerns clearly and which one does not, which one discerns obviously and which one does not—that is, the question of which one takes the lead in discerning. As soon as a thought stirs, these two consciousnesses certainly appear together. Because the manas is the dominant condition (āśraya) of the mind consciousness, where there is mind consciousness there must be manas; the arising of the mind consciousness is the result of the manas's deliberation and selection. Therefore, when the mind consciousness stirs, the manas must already have stirred. If the discernment and thought-activity of the manas were lacking, the mind consciousness would not appear.

Moreover, the manas is an uninterrupted consciousness, existing at every moment, constantly running, constantly clinging, constantly grasping; there is never a moment when it is not stirring thoughts, never a moment when it is not deliberating. The only differences are whether its activity is obvious or not, whether its mental activity is scattered or concentrated, whether it is with attachment or without attachment, and whether the mind consciousness is able to detect its existence and mental activity.

Many people, when their mind consciousness is not stirring thoughts and they cannot observe the manas, feel that they are quite tranquil at the moment, without any thoughts. In fact, at this time the manas does have thoughts; it does have clinging and deliberation (manana)—it is merely that the mind consciousness lacks the wisdom to observe it. Who knows when the manas might make a decision, and then the mind consciousness on its side can no longer settle down and will begin to engage in some action or activity. Every action of body, speech, and mind, whether great or small, slight or significant, is the result of the manas's deliberation. When the manas is about to engage in some activity, the mind consciousness cannot remain tranquil and will inevitably engage in activity following the manas's intentions.