瑜伽論記 20.450

20.450

下釋通經文。世尊乃至此說何等能觀察心者，問能觀體。依何真如而作是說者，問所觀如，下答，三慧是能觀察。依了別真如作如是說者，喻中既說清水淨鏡不撓泉池堪觀面像時，知合中若善修心堪觀真如者知是唯識了別真如，以唯識門一切境界皆是心影，初觀境唯識，後觀識如，名了別如，故云依了別真如作如是說。

Below, it explains and harmonizes the scriptural passage. 'The World-Honored One, down to: what kind of observing mind does this speak of?' asks about the essence of the observing [mind]. 'Relying on what tathatā is this spoken?' asks about the tathatā that is observed. Below, it answers: The three wisdoms are the observing [mind]. 'It is spoken relying on the tathatā of discernment': since the metaphor speaks of clear water, a clean mirror, and an undisturbed spring pool being fit for observing the reflection of a face, one knows that in the application, 'if one well cultivates the mind, it is fit for observing tathatā' refers to the tathatā of discernment that is consciousness-only. Because in the approach of consciousness-only all cognitive objects are images of the mind, one first contemplates that objects are consciousness-only, and later contemplates the tathatā of consciousness, which is called the tathatā of discernment; hence it says 'it is spoken relying on the tathatā of discernment.'