成唯識論述記 7.603

7.603

述曰：種子以識為體，故立「識」名，以種離本識無別性故。種子依本識自體分，亦即名「種子識」，與識不一、異，若為相分亦識所變，體即是識，非離識外別有體性，故立「識」名。

The Commentary states: Seeds have consciousness as their substance, so the name "consciousness" is established, because seeds have no separate nature apart from the fundamental consciousness. Seeds rely on the self-part of the fundamental consciousness, and are also called "seed-consciousness"; they are neither identical with nor different from consciousness. If they are nimittabhāga, they are also transformed by consciousness, their substance is precisely consciousness, and they have no separate substantial nature apart from consciousness; hence the name "consciousness" is established.