According to Nimbarka's Dvaitadvaita philosophy of differential monism, various philosophical terms are understood as follows.
The Highest Reality, according to Nimbarka, is Brahman, Krishna or Hari, a personal God. There is nothing that is equal to Him, nothing that is superior. He is the Lord of all, and Controller of all. He is called Brahman because of the unsurpassed greatness of His nature and qualities, because He is beyond any limit of any kind of space, time or thing.
Brahman is the sole cause of creation, maintenance and destruction of the Universe. All beings arise from Him, nothing that is superior to Him. The Lord alone is the first cause, the manifestor of all names and forms, and none else.
This Brahman is both the upadana (material cause) and the Nimitta (efficient cause). It is the material cause in the sense that it enables its natural saktis, viz. the cit and the acit in their subtle forms, to be manifested in gross forms; and it is the efficient cause in the sense that it unites the individual souls with their respective fruits of actions and means of enjoyments.
Nimbarka discusses two aspects of Brahman. On one hand, Brahman is eternal and great, the greatest of the great, the highest of the high, the creator, etc. of the Universe, high above the individual soul, of which He is the Lord and the ruler. But, on the other aspect He is the abode of infinite beauty, bliss and tenderness, and in intimate connection with the soul. He is the abode of supreme peace, supreme grace, and the ocean of all sweetness and charms.
Thus, Brahman possessed of attributes and adorable by all, has four forms or vyuhas (i.e., Vasudeva, Sankarsana, Pradyumna, and Aniruddha) and appears under various incarnation as Matsya, Kurma etc.
The cit or individual soul is of the nature of knowledge (jnana-svarupa); it is able to know without the help of the sense-organs and it is in this sense that words like prajnana-ghanah svayamjyotih jnanamayah etc. as applied to jiva are to be understood. The jiva is the knower also; and he can be both knowledge and the possessor of knowledge at the same time, just as the sun is both light and the source of light. Thus the soul, who is knowledge, and his attribute, knowledge, though they are both identical as knowledge, can be at the same time different and related as the qualified (dharmin) and the quality (dharma), just as the sun and his light, though identical as light (taijasa), are still different from each other. Thus there is both a difference and a non-difference between the dharmin and dharma; and the extreme similarity between them implies, not necessarily their absolute identity, but only a non-perception of their difference.
The jiva is also ego (ahamarthah). This ego continues to persist not only in the state of deep sleep, (because our consciousness immediately after getting up from sleep has the form slept happily or knew nothing) but also in the state of libera tion. It even belongs to the Parabrahman. Hence it is that Krishna refers to Himself so frequently in the first person in the Gita, of which the chief object is thus Purusottama, who is omniscient and at the same time non-different from the ego or asmadartha.
The jiva is also essentially active (kartr). This quality belongs to it in all its conditions, even after release. But the kartrtva is not independent. The jiva is also enjoyer (bhoktr) essentially in all its conditions.
For his knowledge and activity, however, the jiva depends on Hari; thus, though resembling Him in being intelligent and knower, he is at the same time distinguished from him by his dependence. This quality of dependence or of being controlled (niyamyatva) is the very nature of jiva even in the state of release, just as niyamyatva or the quality of being the controller, forms the eternal nature of Isvara.
The jiva is atomic in size; at the same time his attribute, knowledge, is omnipresent, which makes it possible that he can experience pleasure and pain in any part of the body, just as, for instance, the light of a lamp can spread far and wide and illumine objects away from the lamp. The Jivas are different and in different bodies, and so are infinite in number.
The acit is of three different kinds: viz. prakrta, aprakrta, and kala. Prakrta, or what is derived from Prakrti, the primal matter, aprakrta is defined negatively as that which is not the product of prakrti, but its real nature is not clearly brought out. These three categories in their subtle forms are as eternal as the cit or the individual souls.
[Nimbarka does not explain what exactly the aprakrta is, nor does he define kala more precisely, beyond noticing, as pointed out above,that the aprakrta and the kala are species of the acit. But, Purusottamacarya of the Nimbarka school has, in his Vedantaratna-manjusa, described acit aprakrta as the material cause of the dhama(celestial abode) of Brahman and the bodies and ornaments etc.of Brahman and his associates.
Prakrti, or the primal matter-the stuff of the entire universe is real and eternal like the individual souls, and like them, though eternal and unborn, has yet Brahman for its cause. It consists of the three qualities of sattva, rajas and tamas, such as prakrit, mahat, ahankara etc. (just similar to 24 principles of the Sankhyas).
The jiva has his true form distorted and obscured owing to his contact with karma resulting from ignorance, which is beginningless, but which can come to an end, by the grace of God, when its true nature is fully manifested.It's a part of god.
To attain deliverance, the jiva has to commence with a complete submission to the Paramatman, or prapatti, whose six constituents are:-
1) a resolution to yield (anukulasya samkalpah) 2) the avoidance of opposition (pratikulasya varjanam) 3) faith that God will protect (raksisyati ity visvasah) 4) acceptance of him as saviour (goptrtva-varanam) 5) throwing one’s whole soul upon him (atmaniksepah), and 6) a sense of helplessness (karpanya).
God’s grace extends itself to those who are possessed of these 6 constituents of prapatti, i.e., who are prapanna; and by that grace is generated bhakti consisting of special love for him, which ultimately ends in the realisation (saksatkara) of the Paramatman. For a devotee knowledge of the following 5 things is quite necessary:
1) the nature of the supreme soul, 2) the nature of the individual soul, 3) the fruit of God's grace or moksa, (which is an uninterrupted realisation of the nature and attributes of Brahman, following from the absolute destruction of all action and the consequent extinction of all sentience), 4) the feeling of enjoyment consequent on bhakti, and 5) the nature of the obstacles in the way of the attainment of God, such as regarding the body and the mind as the soul, depending on someone who is neither God nor the preceptor, neglecting their commands, and considering God as nothing more than an ordinary being.
Sri Nimbarka refers to 4 methods of sadhanas:
Karma
Performed conscientiously in a proper spirit, with one’s varna and asrama thereby giving rise to knowledge which is a means to salvation).
Vidya
Not as a subordinate factor of karma but as an independent means.
Upasana or dhyana
It is of three types. First is meditation on the Lord as one's self, i.e. meditation on the Lord as the Inner Controller of the sentient. Second is meditation on the Lord as the Inner Controller of the non-sentient. Final one is meditation on Lord Himself, as different from the sentient and non-sentient.
Gurupasatti
Devotion and self-surrender to guru.
Sri Nimbarkacharya made the "Bhasya" of the Bramhasutra on His Dvaitadvaita Vedanta (Principle of Dualism-Nondualism) in his famous book "Vedanta Parijata Sourabha".