Pratyekabuddhas all realize the twelve links of dependent origination rather than merely understanding them

The Āgamas describe how Pratyekabuddhas contemplate the twelve links of dependent origination in forward order and in reverse order. Although the language describing the Pratyekabuddhas' investigation is rather concise and the cultivation process introduced is rather simple, the Pratyekabuddhas' practice was by no means easy; the intermediate process was winding and arduous. When actually engaging in contemplative practice (vipaśyanā-caryā) and deliberation, they were all in profound meditative concentration (samādhi): the mind consciousness deliberated on one side while the manas deliberated simultaneously, so the results were, of course, all realized through direct practice. Without meditative concentration, there is only the mind consciousness's deliberation, without the manas's simultaneous deliberation, and therefore realization is impossible; one may arrive at intellectual understanding, but understanding is of no use.

As for the Pratyekabuddhas' concrete practical cultivation process, the Buddha could not disclose it in detail; the purpose was to let later people apply effort themselves and realize it through practice. If too much were said, it would easily lead people to mere intellectual understanding, and the effort could not be carried through to completion, so it could only be stated in that simple way. In those simple deliberations and dialogues, one must absolutely not think that the Pratyekabuddhas arrived at a result merely through the mind consciousness's inference and logical reasoning; to say so would be tantamount to slandering the Pratyekabuddhas. The Pratyekabuddhas' meditative concentration was extremely profound; the mind consciousness's function absolutely cannot occupy the dominant position and cannot overpower the manas—the manas's investigation and deliberation must occupy the dominant position. The deeper a person's meditative concentration, the more the manas is employed; conversely, the mind consciousness is used more, relying mainly on the mind consciousness's imagination, inference, and speculation, and the manas cannot be put to use.

By the same token, the Arhats all possessed very deep meditative concentration. In observing the five aggregates (pañcaskandha) of the past and the future, they did not use the mind consciousness's inference, nor inference (anumāna) or erroneous cognition (non-valid cognition); all was direct perception (valid direct cognition) with the manas participating. Because those physical bodies were exactly the same as the present body of the five aggregates, belonging to the same category, by realizing the present one, one knows the past and future ones. For example, suppose there is a batch of products that need to be inspected: because the products are all identical, by sampling and inspecting just one of them, one knows how all the products are. This of course does not include cases where someone has mixed in other products. On the premise that they are guaranteed to be exactly the same, inspecting one or a few is enough to know the whole. Therefore, the Arhats' realization was all realized through direct perception: what it is, it is; there is no imaginative mode of deliberation, no comparative mode of deliberation. For a person without meditative concentration, the mind consciousness's deliberative functions of inference and erroneous cognition are unavoidable.