This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.5 India License.
What is "Sat"?
नासदासीन नो सदासीत तदानीं नासीद रजो नो वयोमापरो यत |
किमावरीवः कुह कस्य शर्मन्नम्भः किमासीद गहनं गभीरम || - Rigveda 10:129:1
THEN was not non-existent (Asatyam) nor existent (Satyam): there was no realm of air, no sky beyond it. What covered in, and where? and what gave shelter? Was water there, unfathomed depth of water?
The primary and most fundamental attribute of "Sat" which is acceptable by all philosophies in India (including Naastika ones like Buddhism and Jainism) is the one that "Exists" in all spaces and times. The Chidaananda attribute is strictly Vedantic interpretation of reality. In a way, the very term "Brahman" is one-sided description of reality. How? Nasadiya answers in following manner.
कामस्तदग्रे समवर्तताधि मनसो रेतः परथमं यदासीत |
सतो बन्धुमसति निरविन्दन हर्दि परतीष्याकवयो मनीषा | - Rigveda 10:129:4
Thereafter rose Desire in the beginning, Desire, the primal seed and germ of Spirit. Sages who searched with their heart's thought discovered the existent's kinship in the non-existent.
Satya and Asatya are siblings - both came into existence together. The very "Idea" of "existence" comes with a corollary of "Non-Existence". Similarly vice-versa. Both these terms cannot exist without each other. In a way, this is also the origin of our "Saamkhya" philosophy. The sages here are describing a point when there was "Absolute Nothing". This state of Absolute Nothingness (or what Buddha calls to as Shunyataa) is what is intriguing.
तिरश्चीनो विततो रश्मिरेषामधः सविदासीत रेतोधाासन
महिमान आसन सवधा अवस्तात परयतिः परस्तात - 10:129-5
Transversely was their severing line extended: what was above it then, and what below it? There were begetters, there were mighty forces, free action here and energy up yonder.
The term Brahman comes from the word-root "BRhat बृह" which means "expansion". One which "expands" is Brahma. One which expands extremely is "Para-Brahma" (usually they are used as synonyms.
This state of "absolute Nothingness" is what yogis, Saamkhyins, Buddhists, contemplate on. But hold on... Was there something even then? Can there be anything else which is more "fundamental" than "Existence"? Furthermore, if Brahman is "Satyam" (as proclaimed by Sri Adi Shankara) then what is "Asatyam"? And both "Satyam (Brahman) and "Asatyam" came into existence simultaneously (this is the "Ved-Vaakyam"). If we assume that time was there then (which isn't the case because the very concept of time requires a 3-D space which wasn't there.
But for the ease of imagination (since our brains aren't evolved to run the simulations of such complexity to create images in mind) we assume that there is some axis relative to which all this is happening. So at point "X" satyam-Asatyam siblings are born. That means they weren't there "before that point". Thus the very term of "Satyam" is shown as "limited". And since Brahman == Satyam, this applies to Brahman as well.
In this scenario, the factually correct statement would be "After that point X, Satyam (Brahman) refers to absolute and complete existence. As alluded in previous paragraph, Space-time came into existence after "Sat" came into existence. Thus Sat still holds true when it comes to its definition as "an entity which is changeless and existent in all spaces in all times". But what beyond/before that? Naasadiya leaves the question unanswered -
को अद्धा वेद क इह पर वोचत कुत आजाता कुत इयंविस्र्ष्टिः |
अर्वाग देवा अस्य विसर्जनेनाथा को वेद यताबभूव || RV 10:129:6
इयं विस्र्ष्टिर्यत आबभूव यदि वा दधे यदि वा न |
यो अस्याध्यक्षः परमे वयोमन सो अङग वेद यदि वा नवेद ||RV 10:129:7
Who verily knows and who can here declare it, whence it was born and whence comes this creation?
The Gods are later than this world's production. Who knows then whence it first came into being?
He, the first origin of this creation, whether he formed it all or did not form it,
Whose eye controls this world in highest heaven, [b]he verily knows it, or perhaps he knows not
All the Moksha-Maargas of India (aastika and naastika who delve this far) are in fact various approaches taken by different people in the quest to answer this riddle which the sages have put. Every body makes their bunch of assumptions and hypothesis and puts forth a theory. But there is always something which remains. Just as it is described in Purusha-sukta. Hence multiple approach is recommended in Upanishads.
As far as Advaita is concerned, this is where the anomaly unfolds as both beginning and end. The necessity of the assumption of "Maya" is required here, and with that, we require a concept of "Maayaadhipati Ishwara". This is a very useful assumption (the assumption that Ishwara exists). I guess to be able to imagine this state of "nothingness", our brain needs to be secreting some weird and special neurotransmitters and chemicals in some special part. All the training by Yogis, the meditative practices, the mind-influencing drugs, is perhaps to induce this state in one's brain. It is one of the life-altering experiences (as described by sages). Yogis call it Kaivalya (Only-ness/Singularity), others call is Advaita, Shunyata (zero-ness), Moksha, nirvana, fanaa (by sufis).
As many saints have said, Bhakti is the simplest way to induce this. You love something which is very grand so intensely that the state is induced and you experienced that which sages state in last two verses of Nasadiya Sukta but couldn't elaborate or explain. But corollary to this is that it would be difficult to be a Bhakta (lover in essence) after knowing that Ishwara (the beloved) is probably just an assumption. But Adi shankara, Santa Gnaaneshwara, Swami Vivekananda and many others have shown that it is possible.
In any case,
In any case,