成唯識論述記 3.334

3.334

述曰：謂外問言，即經部等，薩婆多等。既行難知，應非是識。此「行相」言，但言見分。

The Commentary states: This refers to an external objection, namely by the Sautrāntikas and others, the Sarvāstivādins and others. Since its ākāra is difficult to know, it should not be a consciousness. The word 'ākāra' here refers only to the darśanabhāga.