न तस्य कार्यं? Isn't Ishwara Nimitta Karana?

Question

It says here that Shri Adi Shankaracharya says this in his Brahma Sutra Bhashya.

Now this Saguna Brahman is he with a particular form as per Shankara, let us look at what he says “मन्त्रौ चेमावीश्वरस्य शरीराद्यनपेक्षतामनावरणज्ञानतां च दर्शयतः न तस्य कार्यं करणं च विद्यते न तत्समश्चाभ्यधिकश्च दृश्यते। परास्य शक्तिर्विविधैव श्रूयते स्वाभाविकी ज्ञानबलक्रिया च इति। अपाणिपादो जवनो ग्रहीता पश्यत्यचक्षुः स श्रृणोत्यकर्णः। स वेत्ति वेद्यं न च तस्यास्ति वेत्ता तमाहुरग्र्यं पुरुषं महान्तम् इति च“(Brahma Sutra Chapter 1 Sutra 5)

Translation ” The Mantra here describes Ishwara who is without any need to body and whose knowledge is not covered by anything. “of him there is no cause nor effect, neither is there anyone equal to him nor greater. The power of that Supreme creates everything being of the nature of knowledge, power and activity. He is without feet or arms yet he can walk and grasp, he hears without ears. He knows everything that is to be known but none knows him. Such a person is called the great Purusha” so said by the Mantra”

But isn't Ishwara the nimitta karana or efficient cause of the universe, according to Advaita?

Answer 1

Ishwara is both upadhana karana and nimitha karana as well, owing to Vivarta vada, of Advaita Vedanta. Accordingly Jagat is an apparent (illusory) experience, in the context of Maya, (unscrutable power of Ishwara). Several Prakarana granthas of Advaita vedanta detail it (Vivekachudamani 237,238) .

Panchadashi, Tattva Viveka Prakarana (verse 44)
Jagato yadu pādānaṁ māyā mādāya tāmasīm, nimittaṁ śuddha sasattvāṁ tāmucyate brahma tadgirā
In the Macrocosm, the material cause (upādāna-kāraṇam) associated with Tamas-predominant (Avidyā), and the efficient cause (nimitta-kāraṇam) (associated with) Pure Sattva (Māyā) – both these are the direct meaning of Brahman (as Īśvara), and are referred to as “That” (in “Tat Twam Asi”).
(Translation Chinmaya Foundation)

The Nimitta Karana is the efficient cause of a thing, i.e. the maker of a thing, not the material of which it is made. The Maker or Planner of the universe is Ishwara-M associated with the totally pure Maya made of Shuddha Sattwa. For this reason He is a Super-intelligent Being, knowing everything about the process of creation. The whole blueprint of creation lies in the Consciousness of Ishwara-M. This Ishwara-M is the Nimitta Karana of the Universe.
Commentary Chinmaya Foundation

The mantra cited seems to correspond to Bhagavad Gita 13.14

sarvataḥ pāṇi-pādaṁ tat sarvato ’kṣhi-śhiro-mukham sarvataḥ śhrutimal loke sarvam āvṛitya tiṣhṭhati
(Though) devoid of all the organs, It (still) shines through the functions of all the organs; and (though) verily unattached, (still) It is the support of all; (though) without attributes, (still) It is the enjoyer of the attributes!(Translation by Swami Gambirananda)

Here, Self is only One that pervades all (hence Lord Vishnu-all pervasive) , - as in BG 13.16

bahir antaśh cha bhūtānām acharaṁ charam eva cha sūkṣhmatvāt tad avijñeyaṁ dūra-sthaṁ chāntike cha tat
He exists outside and inside all living beings, those that are moving and not moving. He is subtle, and hence, He is incomprehensible. He is very far, but He is also very near.(13.16)(Translation by Swami Mukundananda)