Does the manas have a starting point?

Question: An arhat liberated in both ways has the ability to extinguish the manas, causing the five aggregates and eighteen realms to disappear. After an arhat liberated in both ways has extinguished the manas, is it possible for the manas to be generated again from the tathāgatagarbha? If that were possible, wouldn't the manas then have a starting point?

Answer: After Nirvāṇa without remainder, when rebirth occurs again, the manas will of course have a starting point. Before entering Nirvāṇa without remainder, however, there is no starting point, because beginningless eons ago there was already one thought of ignorance (avidyā) in the mind, and therefore the manas could not cease.

When entering Nirvāṇa without remainder, the manas ceases—who ceases the manas? Is there one who ceases the manas? If there were, there would still be a self, a master who acts. At the time of approaching nirvāṇa, if the manas had the thought "I want to extinguish myself," with such a mental thought present, attachment would not have been severed, and one could not enter Nirvāṇa without remainder. If the tathāgatagarbha were to extinguish the manas, then the tathāgatagarbha would have the nature of a master, would have that kind of self-nature belonging to the seven consciousnesses, and would no longer be the selfless tathāgatagarbha. Only when the manas has abandoned all thoughts, when not even a single mental factor (caitta) manifests, and the tathāgatagarbha, having no alternative, can no longer transmit seeds—only then can the manas itself disappear.