With wise cognition, one will understand many truths.

Our field of vision is limited, so we cannot see the Earth. Yet although we cannot see the Earth, we know that we ourselves stand upon it, live on it, and rely on it for support and sustenance. Is this kind of knowing a direct perception (pratyakṣa) or an intellectual cognition? It is certainly an intellectual cognition, because by understanding this principle, we can determine that we are indeed on the Earth. It is the same with many of the principles the Buddha taught: they are difficult to realize in the present moment, but relying on the wholesome roots accumulated over many lifetimes, when one cultivates to the point of having the Dharma-selecting eye, through reasoning and judgment that accords with the Dharma, one can know that the Buddha's teachings are correct, that by relying on them one can attain liberation and accomplish the Buddha Way.

For example, the arhats had not yet entered nirvāṇa, but through studying the Dharma and contemplation, they could know that by eradicating the view of self (satkāya-dṛṣṭi) and completely severing craving and attachment to the three realms, liberation could be attained, and in their minds they were certain that this method could lead to liberation and entry into nirvāṇa. Although they had not yet entered it, they did not need to wait until entering nirvāṇa to know that this practice method could lead to nirvāṇa. This is reasoning and judging based on the principles taught by the Buddha, arriving at a correct conclusion. Many things do not require our personal experience to know whether they exist or not, whether they are right or wrong; with cognition grounded in wisdom, one can understand many principles. Without wisdom, even personal experience would not reveal why things are as they are. I sincerely advise all Dharma friends: regarding matters and principles you do not know, do not lightly say "no, wrong, nonexistent, erroneous." Always weigh what level your wisdom has reached, and whether you are capable of correct reasoning, inference, and judgment. The conclusions you reach are not necessarily correct—especially concerning the Dharma spoken by the Buddha: if your judgment is wrong, it constitutes slander, and slandering the Buddha and the Dharma has very serious consequences.