成唯識論述記 7.572

7.572

述曰：此下第九外人問曰：「唯識之義，但心之外更無有物，既有他心異自心之境，何名唯識？許有他色等故。」

The Commentary states: Below is the ninth objection by the opponent: "The meaning of consciousness-only is that outside the mind there is nothing else whatsoever; since there is another's mind, an object different from one's own mind, how is it called consciousness-only, given that you accept other forms and the like?"