The Difference Between the Activities of the Manas and Those of the Mind Consciousness

If the manas is stirred, there will be various reactions on the physical body, such as blushing, a racing heart, shyness, bulging veins, trembling all over, and so on. When the mind consciousness alone is stirred, the body has little reaction and remains relatively calm. The activity of the manas consumes a certain amount of energy, whereas the activity of the mind consciousness does not necessarily consume energy, or consumes comparatively little. Those who only talk but do not act are stirred only in the mind consciousness, while the manas remains unmoved. Those who say one thing and do another speak with the mind consciousness, but the manas has no intention to act, and so they do not act. Those with a habit of deception perform with the mind consciousness, while the manas is not stirred at all. Therefore, to observe a person's character, one should look at how they act, not merely at how they speak; doing is more real than saying. 

If the activity of the mind consciousness consumes energy, it also involves the whole body, because energy flows throughout the entire body; the whole body uses the same stream of energy—energy is not divided into separate domains. It is merely that people who like to think with the brain first consume the energy in the brain; when the brain's energy runs low, the energy of the whole body is then consumed. The brain drives the whole body, so when the brain is tired, the whole body becomes fatigued along with it and needs rest. In the activity of the mind consciousness, there is never a complete absence of the manas' activity; the manas is involved to some degree, so energy is consumed—the more the manas is involved, the more energy is consumed. If I do not ponder problems attentively and merely carry out superficial activity of the mind consciousness quietly all day, I do not feel tired even after a whole day and night, nor do I feel very hungry. But if I ponder problems attentively, I feel tired after a short while and get hungry easily. That is why I am entirely unwilling to engage with people and affairs, unwilling to rack my mind, unwilling to consider unimportant matters—unless they are meaningful and relatively important. 

When investigating Chan with attentive effort, a great deal of energy is also consumed. When cultivating meditative concentration without thinking, not much energy is consumed, and the body instead feels very comfortable and relaxed. Cultivating concentration without thinking is relatively effortless, while contemplative practice (vipaśyanā-caryā) and thinking are brain-burning. When thinking with the mind consciousness, because the mental engagement is shallow and slight, it is relatively fast and easy—one can speak in generalities, flowing like drifting clouds and running water, with a string of clever words—but the content is shallow, reflecting only one's level of knowledge and memory, and rarely revealing one's level of wisdom. When thinking with the manas, however, because the mental engagement is very deep, the consciousness runs more slowly and is more mentally taxing, but the content is profound and far-reaching in significance, revealing a person's deep-level wisdom. 

Let me use a metaphor to illustrate the difference between using the mind consciousness and using the manas. Suppose a person is walking in mud. If the mud is shallow, only reaching the soles of the shoes, walking is still fairly fast and effortless. But if the mud covers the ankles, the calves, or the knees, pulling the foot out is not easy; every step takes great effort, and walking becomes extremely slow. Thinking with the mind consciousness is like walking on a road with shallow mud; thinking with the manas is like walking on a road with deep mud. Therefore, for a person who thinks with the manas, if they remain at the deep level of the manas and are highly focused, then each time a thought shifts or a problem changes, the flow of thought is very slow, requiring the consumption of much energy and feeling somewhat tiring. Such a person thus prefers quietude and does not want people or affairs from outside to disturb them.