成唯識論述記 9.556

9.556

述曰：釋其真義剎那多少，經位雖多剎那，以相相似等，故總說一心。即三心見道依此為證，即是會五十八等一心見道之文。若一心見道，以無間、解脫，并一勝進，名多剎那，總名一心，非無間中復有多念。然於此中有二異說。

The Commentary states: This explains its true meaning regarding the number of moments (kṣaṇa). Although it passes through many moments during the stage, because their characteristics are similar and so forth, it is generally spoken of as a single mind. That is to say, the three-mind path of seeing relies on this as proof, which reconciles the passage in [fascicle] fifty-eight and elsewhere on the single-mind path of seeing. If it is the single-mind path of seeing, with the uninterrupted [path], the liberation [path], together with one advanced [path], they are called many moments, but generally termed 'single mind'—it is not that within the uninterrupted there are again multiple thoughts. However, regarding this there are two different explanations.