With the cognition of wisdom-nature, one will understand many principles.

Our field of vision is limited—we cannot see the Earth. Yet although we cannot see the Earth, we know that we ourselves are standing on the Earth, living on the Earth, sustained and nourished by it. Is this kind of knowing a direct perception (valid direct cognition) or a cognitive understanding at the level of principle? It is certainly a cognitive understanding at the level of principle, because once this principle is clear, we can determine that we are indeed on the Earth. Many of the principles taught by the Buddha are the same: 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 eye of Dharma-selection, through reasoned deliberation and judgment one can know that the Buddha's Dharma is correct, that relying on it one can attain liberation and accomplish the Buddha-way.

For example, the arhats had not yet entered nirvāṇa, but through studying the Dharma and reflecting on it, they could understand that by eliminating self-grasping and completely eradicating craving and attachment within the three realms, one can attain liberation. Their minds were also certain that this method leads 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 leads to nirvāṇa. This is deliberating and judging based on the principles taught by the Buddha, and arriving at a correct conclusion. Many things do not require our personal experience in order 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 leaves one not knowing why things are so. I sincerely advise all fellow practitioners: regarding matters and principles you do not understand, do not lightly say "no," "wrong," "doesn't exist," or "incorrect." Always weigh the level your wisdom has actually reached—can you carry out correct reasoning, inference, and judgment? The conclusions you draw are not necessarily correct. Especially with regard to the Dharma spoken by the Buddha: to judge it wrongly is slander. To slander the Buddha and the Dharma has very serious consequences.