In the Srimadbhagavatam there is a description of the nature of Brahman. Here it is said that Brahman is indicated through the world that is reflecting in It. The reflection is no doubt illusory. This is because the reflection depends upon the original object and the reflecting medium. In the absence of the medium there is no reflection possible. It has no reality the original enjoys. Hence the reflection, pratibimba, being incidental, has no reality which the original has without conditions.
https://sa.wikisource.org/s/asn
सर्वेन्द्रियगुणद्रष्ट्रे सर्वप्रत्ययहेतवे
असता च्छाययोक्ताय सदाभासाय ते नमः १४
Translation:My Lord, You are the observer of all the objectives of the senses. The material world is just like a shadow resembling You. Indeed, one accepts this material world as real because it gives a glimpse of Your existence.
Sridhara Swamin makes a very interesting comment:
8.3.14
सर्वेन्द्रियाणां ये गुणा विषयास्तेषां द्रष्ट्रे | सर्वे प्रत्यया इन्द्रियवृत्तयो हेतवो ज्ञापका यस्य तस्मै | तदेवाह, असता अहङ्कारादिप्रपञ्चेन. छायया ऽसद्रूपया उक्ताय प्रतिबिम्बेन बिम्बम् यथा सूच्यते तथा सूचिताय | तत्र हेतुः, सद्रूपो विषयेष्वाभासो यस्य तस्मै. तदुक्तं तृतीये, “यथा जलस्थ आभासः” इत्यादिना | पाठान्तरे असत्यस्य छायया ऽध्यासेनाक्ताय युक्ताय, तदधिष्ठानायेत्यर्थः ||
The meaning of the above is: All the sensory cognitions/perceptions that we experience are all witnessed by the Pure Consciousness. All these cognitions are indicators, reminders, of Brahman.
[Here Sridhara Swami reminds us of the famous and very important mantra of the Kenopanishad: 2.4:
प्रतिबोधविदितं मतममृतत्वं हि विन्दते ।
आत्मना विन्दते वीर्यं विद्यया विन्दतेऽमृतम् ॥ ४ ॥
Atman is known through every cognition.
Shankara comments: कथं तु तद्ब्रह्म सम्यग्विदितं भवतीत्येवमर्थमाह — प्रतिबोधविदितं बोधं बोधं प्रति विदितम् । बोधशब्देन बौद्धाः प्रत्यया उच्यन्ते । सर्वे प्रत्यया विषयीभवन्ति यस्य, स आत्मा सर्वबोधान्प्रतिबुध्यते सर्वप्रत्ययदर्शी चिच्छक्तिस्वरूपमात्रः प्रत्ययैरेव प्रत्ययेष्वविशिष्टतया लक्ष्यते ; नान्यद्द्वारमन्तरात्मनो विज्ञानाय । अतः प्रत्ययप्रत्यगात्मतया विदितं ब्रह्म यदा, तदा तत् मतं तत्सम्यग्दर्शनमित्यर्थः|
How indeed is Brahman correctly realized/known? The mantra teaches: Brahman is actually known through every cognition. All cognitions are ‘objects’ for the witnessing subject, Atman/Brahman. This Brahman/Atman is indicated, lakshyate, by these very cognitions. There is no other way to know Atman. Thus when Brahman is known as the Atman of all the cognitions, then such a knowledge is the liberating one.
We see that the Bhagavatam is saying exactly this!
Sridhara Swamin continues: Brahman is indicated by the world that is made of ahankara, etc. which are illusory. Just as a reflection is useful in knowing the original image, as told in the Bhagavatam 3.27.12:
यथा जलस्थ आभासः स्थलस्थेनावदृश्यते ।स्वाभासेन तथा सूर्यो जलस्थेन दिवि स्थितः ॥ १२ ॥The presence of the Supreme Lord can be realized just as the sun is realized first as a reflection on water, and again as a second reflection on the wall of a room, although the sun itself is situated in the sky.
For this verse Sridhara Swamin explains: There is the reflection of the Sun in a pool of water in front of a house. The reflection illumines the inside of the house. Those people inside the house, though do not see the Sun directly (as their vision is blocked by the ceiling, walls, etc. of the building), yet are able to experience the illumination of the Sun, though through the medium of the reflection.
This reminds us of the Panchadashi 8th Chapter, Kutastha deepa, where a similar analogy is used by Swami Vidyaranya to establish the Chidabhasa viz a viz the Kutastha Atman.
खादित्यदीपिते कुड्ये दर्पणादित्यदीप्तिवत् । कूटस्थभासितो देहो धीस्थजीवेन भास्यते ॥ १॥
अनेकदर्पणादित्यदीप्तीनां बहुसन्धिषु । इतरा व्यज्यते तासामभावेऽपि प्रकाशते ॥ २॥
1. Just as a wall illumined by the rays of the sun is more illumined when the light of the sun reflected in a mirror falls on it, so the body illumined by Kutastha is more illumined by the light of Kutastha reflected in the intellect (Chidabhasa).
2. When many mirrors reflect the light of the sun on to a wall which is already illumined by the sun, spaces between the various reflections are illumined by the light of the sun alone; and even if the reflections are not there, the wall still remains illumined.
While the Bhagavatam has water as the reflecting medium, the Panchadashi has a mirror to serve the same purpose.
Sridhara Swamin continues the commentary to the earlier stated verse 8.3.14:
In an alternative reading, the meaning would be: Brahman is indicated by the illusory world for which It (Brahman) is the adhishThana, substratum.
The purport is: the world, though unreal, is helpful in knowing Brahman which is its substratum (just like the illusory snake, when inquired into, results in the knowing of the substratum, the rope, the real entity).
The word ‘chaayaa’ in the Bhagavatam verse 8.3.14 is especially interesting as we see this word in the Prashnopanishat mantra 3.3:
आत्मन एष प्राणो जायते । यथैषा पुरुषे च्छायैतस्मिन्नेतदाततं
मनोकृतेनायात्यस्मिञ्छरीरे ॥ ३ ॥
After having elaborately spoken by the Acharya Pipplada about Prana that is the one which has manifested as the perceptible world, the disciple is curious to know the origin, source, of this Prana. To this the Acharya replies: The Prana is born of Atman (Brahman). Just as a shadow (chaya), this Prana is inhering in this body.
The Apte dictionary gives one meaning of ‘chaayaa’ thus: A shadowy fancy, hallucination; असता छाययोक्ताय सदाभासाय ते नमः Bhāg.८.३.१४.
It is this reference to the Srimadbhagavata for the occurrence of this word in the sense of ‘unreal’ that leads us to looking into that text and the commentary of Sridhara Swamin.
An offshoot of the Bhagavatam and the commentary is that it endorses the tenet of Advaita that ‘an illusory object can be an indicator of a real entity.’ This has been laid down by Shankaracharya in the Brahma Sutra Bhashya 2.1.14: कथं चानृतेन मोक्षशास्त्रेण प्रतिपादितस्यात्मैकत्वस्य सत्यत्वमुपपद्येतेति । [How is it that the Veda that is unreal (that is, not having paramarthika/absolute reality), bring about the unfailing/unsublatable, liberating knowledge of Brahman?]
In the Bhagavatam verse 8.13.14 implicitly (in the commentary) and explicitly in 3.27.12 we see that the reflection of the Sun is taught as indicating the real Sun in the sky. So too the mental modifications a person experiences, even though are unreal, superimposed, chaayaa, yet they serve to teach us, identify, Atman/Brahman that is the substratum of these modifications.
In this manner the Srimadbhagavatam studied above has very interesting offshoots that are doctrinally very important for Advaita.
Om Tat Sat