- There are 5 groups of people:
- 1. People with insight from the initial stages of "Hinyana" - that of being hearers of the Dharma ("Śrāvaka-vehicle").
2. People with insight from being independently awakened ("Pratyekabuddha-vehicle")
3. People with insight from the Tathagata-vehicle
4. People of indefinite character
5. People for whom no insight is possible
- The first group - the "hearers" - "do away with the rising of the passions, but not with the habit-energy," or seek Nirvana "within themselves." While they may have knowledge of Nirvana, as long as they "have no insight into the egolessness of things" and thus can't achieve emancipation themselves.
- Hhowever, hearers who see into the egolessness of all things can settle into samadhi and attain the enlightenment of the Tathagata.
- The independently awakened seem to seek to be not engaged with others the way people experience engagement in day-to-day life: "When the teaching to keep themselves away from social relations and entanglements, not to become attached to the external world and its manifold form, to perform miraculous powers by which they can divide their own body and appear double or perform the transformations, is disclosed to them, they are thereby entreated"
- Those of the "Tathagata vehicle" have 1) an insight whereby one sees into the self-nature of things, which is no self-nature; (2) an insight which is the attainment of self-realisation; and (3) an insight into the immensity of the external Buddha-lands. When these three aspects are made known one after another and also when the inconceivable realm where body, property, and abode are seen to be the manifestation of Mind itself, a man will not be frightened, nor terrified, nor show any sign of fear; then such a one is to be known as of the group of people whose insight belongs to the Tathagata-vehicle.
This last bullet point, though repeated elsewhere in the text, is in effect a "test" of "enlightenment." It's not a woo-woo experience per se, and it's not something that can be be faked or that one can "flash upon as needed" as somebody said. While someone might have an experience, the point is actually to live there.
In Section XXI the Buddha summarizes XX himself:
130. The fruit of the Stream-entered [hearer], and that of the Once-to-come [independently awakened]; the fruit of the Not-to-come and Arhatship— all these are due to mental perturbation.
131. The triple vehicle, the one vehicle, and the no-vehicle, of these I talk, for the sake of the dull-witted, and [also] for the wise, solitude-loving ones.
132. The gate of highest reality has nothing to do with the two forms of thought-construction [subject and object]; Where the imageless stands, why should we establish the triple vehicles?
133. The Dhyānas, the immeasurables, and the no-form Samādhis, and the thought-cessation—all these are not at all found in Mind-only.
These are not at all found in Mind-only. All of the mental states associated with the practices of mediation are but a construction of the mind "not at all found in Mind-only."
That's one reason why one should not get too very much hung up over stray thoughts in mediation, I'd opine.