唯識二十論述記 2.189

2.189

述曰：釋第三句「見已無」字，申其難意。正量等計：六識不竝，起此覺時，能見五識實現量者已入過去，現在非有。

The commentary says: This explains the words 'the seeing is already gone' in the third line, presenting the meaning of the objection. The Saṃmatīyas and others maintain: the six consciousnesses do not occur simultaneously; when this awareness arises, the genuine direct perception of the five consciousnesses that can see has already passed into the past and does not exist in the present.