Why Do the Five Consciousnesses Transform Only at the Moment of Becoming a Buddha?

The sixth and seventh consciousnesses transform during the causal stage, while the fifth and eighth consciousnesses become perfect at the fruition stage. This means that the sixth and seventh consciousnesses must continuously transform during the process of cultivation, whereas the fifth and eighth consciousnesses only transform and become perfect at the final attainment of Buddhahood. The process is the causal ground, and attaining Buddhahood is the fruition ground. In this process from cause to effect, the fundamental transformation of the sixth and seventh consciousnesses occurs three times, while gradual transformations occur countless times. Why must the sixth and seventh consciousnesses undergo countless gradual transformations before they can finally achieve perfect wisdom and attain Buddhahood? Because the sixth and seventh consciousnesses are endowed with all kinds of ignorance and afflictions, which must be continuously removed and eradicated through cultivation, while constantly purifying the defilements of the mind, and simultaneously increasing merit and pure wisdom.

Thus, it can be seen that the sixth and seventh consciousnesses are endowed with afflictive natures, and ultimately they will also be endowed with pure nature, bodhi nature, and nirvana nature. This indicates that the sixth and seventh consciousnesses possess both wholesome and unwholesome mental factors, and are not merely neutral in nature; otherwise, they could not undergo such a long period of cultivation, and there might be no need for cultivation at all.

Why do the fifth consciousnesses not continuously transform during the process of cultivation? Because the fifth consciousnesses are entirely subordinate to the mental faculty (manas), serving as tools used by the mental faculty to discern and process sense objects. They completely serve and obey the mental faculty without any independence. Therefore, the fifth consciousnesses have no wholesome or unwholesome nature, and there is no need to cultivate goodness or eliminate evil. Consequently, their nature does not transform, nor is there any need for transformation. However, because the sixth and seventh consciousnesses lack complete merit and wisdom and are at a lower stage, the functions of the fifth consciousnesses, which are the corresponding tools they employ, are also inferior, and the tasks they perform are not perfect or complete. When approaching Buddhahood, the sixth and seventh consciousnesses become perfect in merit and wisdom, complete in virtues, and luminous in nature. The corresponding tools they use must naturally be elevated to the highest level, capable of assisting the sixth and seventh consciousnesses in perfectly accomplishing all tasks without hindrance. In this case, the fifth consciousnesses must correspond to and match the merits of the mental faculty, transforming from the nature of the fifth consciousnesses into the wisdom of accomplished actions, with extremely sublime virtues.