How to Understand the “Constant” in the Constant Deliberation of the Manas?

Question: If the manas is also a dharma subject to arising and ceasing, then how should we understand the "constant" in its constant deliberation (manasikāra)? 

Answer: "Constant" means lasting for an extremely long time; the constancy of the manas can persist even after attaining buddhahood without perishing. However, not extinguishing Him does not mean the manas cannot be extinguished. Arhats and pratyekabuddhas can both completely extinguish the manas and enter nirvāṇa without remainder; bodhisattvas of the seventh bhūmi and above, as well as all buddhas, can completely extinguish the manas yet deliberately choose not to. The manas is produced by the eighth consciousness transmitting consciousness seeds; it can only arise and operate by relying on the eighth consciousness. It is not an originally unborn and unceasing dharma. Once the manas no longer grasps at the worldly dharmas of the three realms, the eighth consciousness will no longer transmit the consciousness seeds of the manas, and the manas will cease. Therefore, the "constant" in the manas's constant deliberation is only spoken of in relative terms with respect to the six consciousnesses, and cannot be compared with the constancy of the eighth consciousness. The constancy of the eighth consciousness is absolute, beyond comparison, whereas the constancy of the manas is relative.