成唯識論演祕 4.92

4.92

釋曰：外人救云：二並何違，故引經難。經意說云：無受身處，無容道理。非約前後，同一身中同類二識一時並生。又不應許此二是一，自性別故。

The exposition states: The opponent saves [their thesis] by asking: 'Why would two arising together contradict [anything]?' Hence the verse is cited as a challenge. The sūtra's intent is to state: There is no place where a body is received, and no possibility in principle, for two consciousnesses of the same category to arise together simultaneously—not differentiated as earlier or later—in the same body. Furthermore, one should not allow these two to be one, because their own-natures are different.