Does Utilizing Manas for Buddha-Recitation and Contemplating Issues Induce Fatigue?

When reciting the Buddha's name, simply recite it. There is no need to mentally contemplate the various merits of the Buddha or ponder how to recite effectively to achieve results. This consumes relatively little mental effort and energy. If the duration of recitation is not excessively long and one eats normally, one is unlikely to feel particularly tired. However, when first learning to recite using the manas (mind root), due to unfamiliarity, it requires more mental application and one may feel somewhat tired. Once recitation gradually enters the state of samadhi, where meditative concentration is relatively deep, the flow of qi and blood is good, nourishment is sufficient, and energy is ample, the feeling of tiredness disappears. Instead, the physical body experiences lightness and ease, and the spirit feels joyful. In the state of samadhi, energy consumption is extremely low.

Using the manas to contemplate problems differs from reciting the Buddha's name. When contemplating problems, mental effort is required, consuming more mental energy and vitality. Without sufficient energy supply, one will feel tired. During Chan (Zen) meditation, the primary activity is the investigation and deliberation of the manas, which requires mobilizing the nervous system. The high energy consumption leads to a strong feeling of fatigue. Therefore, those who practice Chan meditation tend to eat more, just as those who engage in heavy mental work have larger appetites. They also need to rest periodically; otherwise, they will feel very tired. However, if one is in a state of very deep meditative concentration (dhyana), the ample qi and blood allow energy to be replenished adequately, making it less easy to feel tired. Shallow meditative concentration, on the other hand, makes fatigue more likely. If Chan meditation enters a very deep state of samadhi, where the flow of qi and blood is optimal, and the body and mind are light, at ease, and joyful, one will not feel tired.

Contemplating with the manas consumes more energy, while thinking with the consciousness (vijnana) consumes less. This is because contemplation using the manas requires engaging the brain's nervous system, which consumes energy and thus causes fatigue. The entire nervous system is mobilized by the manas; the consciousness cannot mobilize it. Therefore, thinking with the consciousness is relatively effortless. Even if thoughts are very scattered, thinking about everything, one does not feel particularly tired. Consequently, many people prefer using the consciousness and are unwilling to engage in deep contemplation and investigation.