All facts cannot be realized without meditative concentration (samādhi).

In a single instant (kṣaṇa), 81,000 seeds of consciousness arise and cease. In the time of a finger snap, there are ninety kṣaṇas, and a finger snap takes at most one second. After the manas makes contact with mental sense-objects, for the mind consciousness to arise again, make contact with the mental sense-objects, and discern them—this takes less than 0.01 seconds, not even half a kṣaṇa. Such a short interval probably cannot be measured by instruments; only in extremely, extremely deep meditative concentration (samādhi), when the mind consciousness becomes extremely subtle, can it be perceived. Before the eighth bhūmi, bodhisattvas simply have no way to perceive it. Therefore, there are extremely many truths of reality that cannot be realized without profound meditative concentration. If one does not cultivate meditative concentration and yet hopes to realize some Buddha-dharma, that is impossible. Without meditative concentration, everything relies on inference, guessing, and conjecture. What is deduced through reasoning and analysis brings no beneficial experience of merit and cannot dispel doubt.