Is the Self-Witnessing Portion of the Eight Consciousnesses Able to Continuously Manifest and Operate?

The self-witnessing portion, which refers to the capacity for introspection and the power of awareness and perception, does not constantly manifest in the seventh consciousness due to insufficient meditative concentration and wisdom. Without these, the conscious mind lacks the ability to introspect or reflect upon itself. In contrast, the eighth consciousness perpetually possesses this introspective power and self-witnessing portion, as its concentration and wisdom are eternally present, unchanging, neither increasing nor decreasing, existing inherently without requiring cultivation.

For instance, the self-witnessing portion of the sixth consciousness (mental consciousness) requires strong concentration and wisdom to continuously illuminate the mind itself. The method of observation taught by the Buddha in the Mahāsatipaṭṭhāna Sutta is precisely this practice of illuminating one’s own mind: one must be aware of whatever they are doing. With this awareness, the mind attains stability; without it, the mind becomes scattered. Why did the Buddha teach this? Because sentient beings’ minds are habitually scattered and unable to perceive their own minds. Perceiving one’s own mind is the self-witnessing portion; without this perception, the self-witnessing portion is absent.

Those who possess introspective power and can perceive their own minds do so partly due to a certain degree of wisdom and partly due to a certain degree of concentration. This holds true regardless of whether one studies Buddhism or not. Thus, individuals differ in wisdom: some understand themselves, while others do not. Similarly, the other consciousnesses operate in this manner—the self-witnessing portion cannot always manifest and function continuously.

The self-witnessing portion is the power of introspection, enabling one to observe what one is doing, what one has already done, and what one intends to do. This process inherently involves the seeing-part and the appearing-part, and it cannot be separated from the self-witnessing portion. The “what” in “doing what” corresponds to the appearing-part; the “doing” corresponds to the seeing-part; “doing what” constitutes the self-witnessing portion; and knowing what one has done constitutes the self-witnessing portion.