A Concept called "Saamaanaadhikaranyam" which is a technical grammatical concept, is used to explain the verse "Tat Tvam Asi" clearly.
"Saamaanaadhikaranayam" means "co-ordinate predication". It means that co-ordinate predicate terms are used to identify the substantive.
The great grammarian of Sanskrit named Patanjali has defined this concept "Saamaanaadhikaranyam" as follows:
The meaning of this is as follows: An identity of a single entity is signified/denoted by several terms, each term denoting that entity based on each of its various inseparable attributes. That is different words possessing different grounds of meanings denoting a single entity is what is called "Saamaanaadhikaranyam".
The reader may find this bit confusing.
Let me explain it using an example. Please consider in Sanskrit the terms "Neela: Ghata:" meaning "Dark Pot". Here the term "Neela:" is denoting the entity by that entity's inseparable attribute "Darkness/Blackness". The Term "Ghata:" again denotes the same entity by its nature of having narrow neck and broad spherical body. Therefore the "Neela:" term denotes the entity on the ground of meaning "Darkness" "Neela Roopam" which is an attribute/mode of the entity. Similarly the "Ghata:" term denotes the same entity (Pot) on the ground of the entity's mode of being narrow-necked with broad spherical body.
The verse of the Veda "Tat Tvam Asi" is understood clearly using the concept of "Saamaanaadhikaranyam" as follows: The term "Tat" (that) denotes the Brahman on the grounds of its attributes/modes namely "being the only cause of the universe", "having infinite divine characteristics", "untouched by all impurities". The term "Tvam" (you) denotes the same Brahman on the grounds of it having the Jeevaatman (Chit) as his attribute/mode. Therefore the Sareera-Aatma Bhaavam (Body-Soul relationship) between the Universe and the Brahman is clearly told by the verse "Tat Tvam Asi".
As the above mentioned concept is vital, it was thus outlined in simple words as far as possible. Its detailed explanation will follow in future lessons.
Let us now do a contemplation on the "Tatva-Hita-Purushaartham" through the divine words of Bhagavath Ramanuja as follows:
This is the essence of our Visistadvaita Shree Vaishnava philosophy and practice. The Tatva-Hita-Purushaarthas are beautifully conveyed by this verse. "Tatva" means reality of existing entity. "Hita" denotes "means". "Purushaartha" means "Goal".
"Chit" denotes the sentient soul - jeevaatman. The Jeevaatman is identified as
"Achit" denotes the insentient matter. Its nature is to change from one form to another. It neither knows itself nor anything. Trigunya (matter having Satva, Rajas and Tamas), Satva Soonya (Time which is devoid of Satva) and Sudha Satva (matter having pure Satva without rajas and tamas) are the three types of Achit.
further explaination of tatva trayam is explained in lesson 5
"Asesha" denotes that there are innumerable Jeevaatmans. It applies for both Chit and Achit. Upto this, it is clear that chit and achit are different entities. "Asesha Chitachit Vastu Seshine" means that the Brahman has all the chit and achit entities as his property. The term "Vastu" brings out the truth that these chit and achit entities are real and not falsehood/illusion. This makes it clear that the Brahman is different from all chit and achit entities and therefore the Brahman is "Purushotthaman" as "Seshe" denotes clearly that Brahman is the lord/owner of all chit and achit entities.
"Sesha Saayine" denotes that the Brahman reclines on the divine bed, which is the coil of Adi Sesha - divine serpent. This further implicitly denotes that the Brahman has divine form, divine abode, divine consort Shree, Bho and Nila and all the divine royal things signifying his unparalleled and unsurpassed supremacy.
Therefore the part of the verse "Asesha Chitachit Vastu Seshine Sesha Saayine" brings out the meaning that the Brahman has "Ubhaya Vibhuthi" as his property. "Ubhaya" means "Twin" and Vibhuthi means property. They are the Leela Vibhuthi (the material worlds (from Chaturmuka Brahmaa's Satya Loka to microorganisms) which are created sustained and destroyed by Brahman as his sport (leela) and exists for his Leela rasa) and the Nitya Vibhuthi which is the transcendental divine world called Shree Vaikunta Paramapadam.
This part of the verse therefore implicitly brings out the Pradhaana Pratitantram (key point) of Visistadvaita, which is the sareera-aatma bhaava relation between the all chit - achit entities and Brahman. As the Brahman supports, controls and owns all chit-achit entities he is the soul of all chit-achit entities. As all the chit-achit entities are supported, controlled and owned by Brahman and exist for the purpose of Brahman as inseparable attribute of Brahman, all the chit-achit entities are Brahman's body.
"Nirmalaananta Kalyaana Nidhaye" brings out the Ubhyalingam - the two identifications of Brahman. As follows: "Nirmala" brings out "Akila Heya Pratyaneekatvam" meaning "the Brahman is pure untouched by all the impurities of the universe though he is present inside and outside everything. He is "Aatma" soul of the universe called "Antaryaami" - meaning "He who controls everything by being present inside everything". "Ananta Kalyaana Nidhaye" brings out "Ananta Kalyaana Gunaakaratvam" meaning "the Brahman is infinite with infinite divine/auspicious attributes like power, strength, lordship, firmness, knowledge, resplendence which are beyond the reach of our mind, sense organs and words. These attributes bring out his "Paratvam" "ultimate supremacy". His attributes/qualities like divine mercy brings out his "Sowlabhyam" "Easily available" nature.
"Vishnave" clearly points out that the Brahman is Lakshmi Pathi (Lord of Shree Lakshmi) who pervades everything everywhere. Vishnu (Shreeman Narayanan) is the Brahman. His omnipresence is conveyed by this name.
To summarise the Iswara Tatva concept, please note the following points:
Up to this Visistadvaita Tatvam (reality) was outlined.
"Namaha" is not in the meaning of just saluting Lord Vishnu. It conveys the "Hitam and Purushaartham" implicitly. Hitam is means to attain liberation. The term "namaha" conveys meaning up to Saranaagathi at the lotus feet of Shree Vishnu, which is total surrender. Similarly Bhakthi is also to be understood to have been conveyed here implicitly.
"Namaha" with the names of Vishnu used here also implicitly conveys the "Purushaartham" (goal, result) which is eternal service at the lotus feet of Lord Vishnu and eternally experiencing the Lord in Shree Vaikunta Paramapadam.
The "Hitam" and "Purushaartham" will be explained in detail. The reason for presenting here the "Tatva-Hita-Purushartham" in a summarized form is just to stress that these concepts are to be carefully followed and contemplated again and again for comprehension.
As the level of presentation of Visistadvaita Shree Vaishnava philosophy and practice in the lessons are gradually getting higher, it is requested that the reader reads these lessons more than once for better comprehension. Also, referring to earlier lessons whenever required is advisable in this context. Please get back to me if you have any sort of doubt/question as the concepts which are being presented and those going to be presented are very important from the point of clear comprehension of Visistadvaita Shree Vaishnavam. Please do not hesitate to write to me.