唯識二十論述記 2.202

2.202

述曰：曾現受境，明了五識，既許非無，能見此心追憶意識，亦定是有。彼此二宗許曾現識現量所攝，現量曾有境，今時方能憶，故此所緣，定心外法。又追憶識，由曾現受，亦現量攝，故知外境實有義成。若無外境，無曾所受，無曾所受故，現量亦無，云何今時有憶持識？由斯外境實有成也。

Commentary: Since the clear five consciousnesses that directly experienced the object in the past are conceded not to be non-existent, the remembering mental consciousness that sees this mind must also definitely exist. Both systems concede that the past direct consciousness is subsumed under direct perception; direct perception once had an object, and only then can one now remember it; therefore, what is apprehended is definitely an entity external to the mind. Moreover, the remembering consciousness, due to past direct experience, is also subsumed under direct perception; thus one knows that the meaning that external objects are real existents is established. If there were no external objects, there would be no prior experience; because there would be no prior experience, direct perception would also be non-existent; how then could there now be a consciousness that remembers and retains? Thereby external objects are established as real existents.