Clarity and Lucidity of Thought in Dhyāna

If the train of thought is not clear enough, it indicates a lack of meditative concentration (dhyāna). One should cultivate concentration more diligently to make thinking clearer. When the power of concentration is insufficient, conscious thought cannot follow a single main thread; it becomes scattered and unfocused, lacking emphasis. This is similar to how the flow of vital energy (qi) and channels (meridians), not following a single line, wanders aimlessly throughout the body. A person with strong logical thinking ability relies on powerful concentration to achieve single-minded focus, like an awl penetrating deeply into a single point. A person without concentration is like a wooden plank lying flat on the ground, leaving no trace.

If the power of concentration is sufficient and correct understanding (view) is also sufficient, one should combine it with the stillness-based concentration cultivated during seated meditation (dhyāna) to strengthen concentration. Then, one should contemplate the Buddha Dharma and contemplate the five aggregates (skandhas). After that, one engages in Chan (Zen) investigation, maintaining the sensation of doubt or inquiry at all times. First, sever the view of self (sakkāya-diṭṭhi), then investigate Chan to illuminate the mind (ming xin).

The purpose of studying the Dharma is for contemplation and then realization. If one cannot engage in contemplation, it indicates that the power of thinking is not good enough, meaning the power of concentration is insufficient. Meditative concentration without the cultivation of thinking (thinking meditation) is of little use for realizing the Dharma. Therefore, one should learn to cultivate concentration so that meditative concentration can fulfill its proper function.