This is the premise that leads to the conclusion that there is no ‘personal’ enlightenment. It strikes me as a Zen teaching, but perhaps I am wrong. I have been reading more on this subject recently, as they are a very interesting sect, with a very interestingly distinct way of expressing the dharma through their language.
The nonduality of object-subject is predicated on the subsumption of the object into the sensory world of the subject, the ‘true reality’ of the object being ungraspable by the senses, unaccessible to the subject.
That does not mean that the object does not exist. I think that this is true from the perspective of Zen as well, influenced as it is by Yogācāra.
From the Yogācāra Master Dharmakīrti in Saṃtānāntarasiddhināmaprakaraṇa (Proof of Others’ Continua) 2:
The Cittamātra perspective also accepts that those representations, in which other’s actions and speech appear to us, would not have existed, if the special processes of other consciousnesses were not there.
& similarly in 76:
Having known, through this inference, the existence of other mind, the mind as subject successively produces the effects which lead to the desired aim.
Translation Ramesh Kumar Sharma. His translation is not available online, but you can read a paper that he wrote on the text here if you wish.
In short, mind-continuity (心相續/*cittasaṃtati) is distinct, in most Mahāyāna at least, and I can only say that as far as I am aware, and I most definitely presume for the Buddhadharma of the EBTs, though the word cittasantāna (*cittasaṃtati is a hopefully-scholarly reconstruction of my own, do not quote it if you want people to recognize it, cittasantāna is the ‘proper’ form) is unlikely a vocabulary item of that dispensation.
If it were not the case that mind-continuity 心相續 is collectively distinct, then how can the Buddha have an enlightened continua and you an unenlightened continua if enlightenment is dependent on others’ enlightenment? Your enlightenment is dependent on the Buddha’s. The Buddha is enlightened, why aren’t you, or me, for that matter?