The five object-specific mental factors (kleśa-free mental factors, viśeṣa-caitta) cannot manifest at all times and in all places

The five universal mental factors of the seventh consciousness include: desire (chanda), determination (adhimokṣa), mindfulness (smṛti), meditative concentration (samādhi), and wisdom (prajñā) — five mental factors. Because of ignorance, among these five mental factors of the seventh consciousness, meditative concentration, wisdom, and determination cannot manifest and operate at all times and in all places, but only manifest and operate at certain times. Because of ignorance, the seventh consciousness sometimes lacks meditative concentration; because of ignorance, the seventh consciousness sometimes lacks wisdom; because of ignorance, the seventh consciousness sometimes cannot attain determination regarding the meaning of the Dharma. If ignorance is eradicated and no longer obscures the seventh consciousness, the seventh consciousness will be able to remain in meditative concentration at all times and in all places — such is the case with bodhisattvas at the eighth ground and above and all Buddhas; having wisdom at all times and in all places, being able to attain determination regarding the meaning of the Dharma at all times and in all places — such is the case with all Buddhas.

Yet the fundamental Buddha, the true suchness undefiled consciousness (amala-vijñāna) of all Buddhas, is at all times and in all places in meditative concentration, possesses great wisdom, and can attain determination regarding all dharmas, without ignorance. The eighth consciousness of sentient beings is also like this, but the content of its meditative concentration, wisdom, and determination differs from that of the seventh consciousness. The seventh consciousness has meditative concentration, wisdom, and determination regarding the Four Noble Truths, whereas what the eighth consciousness attains determination regarding is not worldly dharmas; its meditative concentration is not worldly concentration, and its wisdom is even less worldly wisdom.

The mindfulness (smṛti) and desire (chanda) mental factors of the manas impel the arising of eye consciousness

Original text of the Zuochan Sanmei Jing (Sitṛṣṇā-samādhi Sūtra):云何心。是心无常。从因缘生故。生灭不住。相似生故。但颠倒故。谓是为一。本无今有。已有还无。是故无常。观知心空。云何为空。从因缘生。有眼有色可见。忆念欲见。如是等和合。眼识生。

Explanation: What is the conscious mind? These consciousnesses are impermanent dharmas, arising from various causes and conditions. After arising, they constantly arise and cease, change, and do not abide; it appears that consciousnesses have arisen — these are the six consciousnesses. Because the minds of sentient beings (the manas) are inverted, they take the six consciousnesses to be permanent and unchanging. In fact, these consciousnesses did not exist originally but have only now arisen, and after arising they will cease; therefore they are said to be impermanent.

Contemplate these minds and know that they are all empty, produced by the conjunction of causes and conditions. For example, the arising of eye consciousness: one condition is that there must be the eye faculty; one condition is that there must be material sense-objects to be seen; one condition is that there must be mindful recollection; one condition is that there must be the desire to see. Only when these causal conditions conjoin can eye consciousness arise. The arising of mind consciousness is also like this.

Then a problem arises: 1. Which consciousness must engage in mindful recollection for eye consciousness to arise? 2. Which consciousness must desire to see forms for eye consciousness to arise? It is the recollective nature and the desire-to-see-forms nature of the manas that induce the eye consciousness to see forms; it is not that the recollection and desire-to-see-forms of mind consciousness give rise to eye consciousness, because at this time mind consciousness has not yet appeared, and even if mind consciousness were present, eye consciousness is not born from the recollection and desire-to-see-forms of mind consciousness. Therefore the manas must have the mindfulness mental factor and must have the desire mental factor. Eye consciousness seeing forms is not driven by mind consciousness; it must be driven by the manas. All dharmas arise impelled by the manas. Therefore the manas must possess the recollective nature, the mindfulness mental factor, and the desire mental factor, so that the myriad dharmas can operate in the world.