What is the principle behind quenching thirst by thinking of plums and salivating upon merely hearing about plums?

What is the principle behind "quenching thirst by imagining plums" and vomiting sour water upon hearing about plums? Without drinking water or eating anything, the problem of thirst is resolved—who resolved it? When one is thirsty, there is no saliva; when there is saliva, the mouth is no longer thirsty. How does the saliva appear? The brain issues a command, transmitting it to various parts of the body, or to a certain part, and a certain reaction occurs. Who issues the brain's command? It is issued by the manas; the tathāgatagarbha executes the command, supplying what is needed, satisfying the manas, and fulfilling the manas' aim. Therefore, if the manas had no desire, could states appear? No state whatsoever would appear, and no change whatsoever would occur.

Why does the manas, upon hearing about plums, vomit sour water? The "hearing" here is, of course, the hearing of the ear consciousness and the mind consciousness, which then transmit the information to the manas, and the manas thereby knows about the plums. Knowing that plums are sour, and knowing what the nature of plums is—is this known by the mind consciousness, by the manas, or by both? Based on past experience, having known the nature and function of plums, one's imagination runs wild, as if the plums were truly in one's mouth. The manas is deceived and kept in the dark, and it causes the material body to produce the corresponding reaction, so the sour water appears in the mouth, and thus the problem of thirst is temporarily resolved.

From this we can see that when the mind consciousness engages in erroneous cognition (non-valid cognition) in its discernment, and the manas does not know it has been deceived, abnormal phenomena appear. It is evident that, since beginningless kalpas, the mind consciousness has not seldom deceived the manas, and then the manas in turn makes things hard for the mind consciousness.

The solitary mental consciousness imagines itself standing at the edge of a cliff, and so the soles of the feet turn clammy and the whole body trembles; out of fear of falling, it tightly controls the body faculty, tensing it. Who caused this? It was caused by the manas, as the result of the tathāgatagarbha activating and cooperating. Because of the mind consciousness's improper mental engagement, the manas engages in improper mental engagement, and then issues erroneous emergency measures and commands, resulting in abnormal reactions of the body faculty.

Since beginningless kalpas, the mind consciousness's false teachings to the manas have caused the manas to keep walking along wrong paths, unable to return to the right way. The mind consciousness's false teachings are the result of being directed by the manas's ignorance and delusion. If the manas had no ignorance, the mind consciousness would certainly always be enlightened, and there would be no wrong views, wrong understanding, or false teachings, and the manas would likewise never have wrong views.

You deceive me, and I deceive you—this is cause and effect. If you are wrong, I am wrong, and then I make you wrong—this is cause and effect. Therefore, the cause of the transmigration through the three realms and six paths, the cause of birth and death, is the manas's ignorance. And the manas's ignorance has existed since before beginningless kalpas, stored within the tathāgatagarbha, enabling the tathāgatagarbha to give birth to birth and death—this is the suffering of transmigration.