The Mysteries of Chan Practice

In the investigation of all dharmas, at the beginning it is the manas cooperating with the mind consciousness in thinking and analysis, with the mind consciousness gathering various data and information; when the mind consciousness has gathered sufficiently complete information, enough for the manas to make use of, the mind consciousness must then cooperate with the manas's deep deliberation, cooperate with the manas's work of processing and integration, cooperate with the manas's work of examination and filtering, letting the manas expend more mental effort while the mind consciousness becomes less active—then the work of investigation can be completed very quickly.

If you want the mind consciousness to engage less in active thinking and the manas to deliberate more, you must cultivate meditative concentration (samādhi); only within concentration can the manas's focused investigation be guaranteed. Although He cannot be completely fixed on one single object, it is enough for Him to be fixed on a very few dharmas: apart from the dharma meanings that require focused investigation, everything else only needs to be lightly cognized, without interfering with one's own investigation. Thus Chan investigation must take place within concentration; the mind consciousness must not rely on emotional conjecture and intellectual understanding, but must make extensive use of the manas's deliberative nature, giving full and effective play to the manas's deliberation, and personally realize the tathāgatagarbha—this is the secret of Chan investigation. Therefore, if the manas does not realize the Dharma, it is impossible to see the mind and attain enlightenment, and likewise impossible to eradicate the view of self (satkāya-dṛṣṭi). When investigating Chan within concentration, the use of the mind consciousness's thinking is relatively little, while the use of the manas's deliberative nature must be great—that is why realization comes easily. This is the secret of Chan investigation and contemplation.