大乘起信論廣釋卷第三．四．五 3.54

3.54

Treatise: "Arising from non-awakening [...] therefore it is called manas." Commentary: Next is the explanation of the evolving of the manas. In this there are three parts: first, briefly clarifying the evolving of the manas; second, extensively revealing the characteristics of evolving; third, concluding their reliance on the mind. This is the first.

Here, it reveals the five kinds of consciousness-characteristics: "Arising from non-awakening" is the karmic consciousness; "capable of seeing" is the evolving consciousness; "capable of manifesting" is the manifesting consciousness; "capable of grasping sensory objects" is the cognitive consciousness; "giving rise to continuity of thoughts" is the continuing consciousness. Since these arise from avidyā deludedly obscuring the real and exist falsely, the first three form the ālayavijñāna, and two arise by mistaking the false for the real, the latter two characterizing the phenomenal consciousness. Since these five kinds combine into two consciousnesses, through the meaning of two reliances they are collectively called manas:
First, reliance of the derivative on the fundamental: because the derivative relies on the fundamental, and the first three are the fundamental, they are called manas.
Second, reliance of the coarse on the subtle: because the coarse relies on the subtle, and the latter two are subtle, they are also called manas.
The coarse mental consciousness is neither fundamental nor subtle, and lacks the meaning of being that upon which something relies; therefore it is not called manas, but because it merely possesses discrimination, it is called mental consciousness.