What Is Meant by the Inner and Outer Factors of Enlightenment?

The first of the seven factors of enlightenment is the mindfulness factor of enlightenment (smṛti-saṃbojjhaṅga). The internal mindfulness factor is the mindfulness of the manas, while the external mindfulness factor is the mindfulness of the mind consciousness. When the manas lacks the mindfulness factor of enlightenment, the mindfulness factor of enlightenment cannot be accomplished, and the investigation-of-dharmas factor of enlightenment cannot manifest. Therefore, the manas definitely possesses the mental factor of mindfulness. The Hīnayāna sūtras already implicitly speak of the manas's mental factor of mindfulness, let alone the Mahāyāna sūtras. It is only because sentient beings are heavily obscured by ignorance that they cannot understand the Buddhist sūtras and are unable to discern this.

Judging from the World-Honored One's description of the seven factors of enlightenment, the manas possesses the investigation-of-dharmas factor, the diligence factor (true diligence), the joy factor (the manas does not experience only neutral feeling), the tranquility factor, the concentration factor (corresponding with meditative concentration), and the equanimity factor. Only when the mental activities afterward conform to the Noble Eightfold Path can the conditions for attaining the fruits of realization in the Small Vehicle be complete, so that one can eradicate the view of self (satkāya-dṛṣṭi) and realize the first fruit; otherwise, all such fruits are false fruits, plastic fruits. When the conditions are not complete and the causes and conditions are not complete, forcibly guiding someone can only yield a false fruit.

Among the seven factors of enlightenment, there is the investigation-of-dharmas factor. When one cultivates to this stage, one gains the ability to discern. However, when something far exceeds one's current level, one again lacks the capacity for discernment, and then one must continue cultivating. The investigation-of-dharmas factor must be continuously advanced until it is perfectly complete, so that one can immediately and correctly discern all dharmas without doubt.