The works of Ādi Śaṅkarācārya

Svātmaprakāśikā

Verse 41

प्रत्येकं जीवता नास्ति बुद्धेरपि जडत्वतः ।जीव आभासकूटस्थबुद्धित्रयमतो भवेत् ॥ ३८ ॥

In plain words

Take them one at a time and none of them is a living self. Not the intellect either — it is inert. So the jīva must be all three at once: the reflection, the changeless witness, and the intellect.

Close to the Sanskrit

Taken singly, jīva-hood does not exist; nor of the intellect either, because of its insentience. Therefore the jīva would be the triad of reflection, the unchanging witness, and the intellect.