Chan contemplation means using the mind consciousness to investigate the tathāgatagarbha

Investigating Chan means that we use the conscious mind of seeing, hearing, awareness, and knowing to seek the tathāgatagarbha, which is without seeing, hearing, awareness, or knowing. To see one's true mind and realize one's nature, one must use the method of investigating Chan and investigating the huatou. Investigating Chan and the huatou means using the mind consciousness—the consciousness endowed with the wisdom mental factor that can know mental dharmas—to investigate the tathāgatagarbha; only the mind consciousness has this functional capacity. And in investigating the tathāgatagarbha, one must investigate Him with sufficient meditative concentration (samādhi). It is best to give rise to a questioning doubt in the mind, to raise questioning doubt toward all the activities of one's own five aggregates (pañcaskandha), keeping that questioning doubt suspended in the mind at all times, or suspending a huatou, and then to contemplate and probe the questioning doubt; in the end, the questioning doubt can be resolved.

Do not use the mind consciousness to make rough analysis, deliberation, and imagination. Such emotional thinking and intellectual interpretation is at most intellectual understanding/interpretive awakening; it cannot be genuine direct realization, and it cannot give birth to wisdom—perhaps one cannot even achieve interpretive awakening. If one cannot attain direct realization but only interpretive awakening, then prajñā wisdom will be very difficult to bring forth, the path ahead will be difficult to walk, and afflictions will not be easy to subdue. It would be better to first lay a firm foundation in all respects and then seek enlightenment. If one awakens after laying a firm foundation, the wisdom will be deep and sharp, afflictions can be effectively subdued, and one can obtain genuine merit and real benefit.