The system of Philosophy based on upanishad is called the Vedanta Darshan. It is called Vedanta because they are literally the concluding portion, the end of vedas, secondly they are essence, the cream, the height of vedic philosophy.  The passages in upanishads are manifold. Some of them clearly speak of the identity of individual soul with supreme being, while there are passages which speak of the difference between the individual soul, the God and the matter. Such passages have given rise to the different interpretations and vyasa (Badaryana) wrote the brahmasutras in order to clear the apparent contradictions of the upanishad passages and show that fundamental doctrine of all the Upanishads is the identification of individual soul(Jiva) with supreme soul (Brahman). The ultimate cause of all false impressions is Avidya or ignorance. The illusion caused by Avidya vanishes through viveka or true knowledge.

Founder & Commentators

Along with Badari and Jaimini, Badarayana, a contemporary of Jaimini, was the other major interpreter of Vedic thought. Badarayana approves of the Mimamsa view that the relation between words and their significations is eternal. There are, however, clear statements of difference: according to Jaimini, for example, the dispenser of the “fruits” of one’s actions is dharma, the law of righteousness itself, but for Badarayana it is the supreme lord, Ishvara. The overall difference that emerges is that whereas Jaimini lays stress on the ritualistic parts of the Vedas, Badarayana lays stress on the philosophical portions—i.e., the Upanishads. The former recommends the path of Vedic injunctions, hence the ideal of karma; the latter recommends the path of knowledge. The central concept of Jaimini’s investigation is dharma—i.e., what ought to be done; the central theme of Badarayana’s investigations is brahman—i.e., the Absolute Reality. The relationship between these two treatises remains a matter of controversy between later commentators—Ramanuja, a great South Indian philosopher of the 11th–12th centuries, defending the thesis that they jointly constitute a single work with Jaimini’s coming first and Badarayana’s coming after it in logical order, and Shankara, an earlier great South Indian philosopher of the 8th–9th centuries, in favour of the view that the two are independent of each other and possibly also inconsistent in their central theses.

Advaita Philosophy

Gaudapada is regarded as the systematic expounder of Advaita philosophy. His mandukya Karika or Gaudapada Karika also known as the Agama-sastra is the first available systematic  treatise on Advaita Vedanta. The fundamental doctrine of Gaudapada is the doctrine of No origination (Ajadivada). It means that world being only an appearance is infact never created. Absolute being never created. Advait Philosphy works on following concepts:

Brahman: Brahman is the only reality, it is absolutely indeterminate and non-duel. It is beyond speech and mind. The description of it is through the negative formula ‘neti neti’. The basic cause of universe and the cause of all causes is called Brahman by the Upanishads. The world rises out of him, is supported by him and dissolved into him. It is the pure consciousness, it is the self-luminous, and which transcends subject object duality. There is no duality and no diversity at all.

Ishwara: Ishwara is the personal aspect or impersonal Brahma. Ishwara is known as saguna brahman. IShwara is perfect personality. He is the lord of Maya. Sankara says there is no multiplicity here that one who sees the many here is doomed to death. The object of the world are denies sperate individual experiences. Brahman is also described not as creator but as a reality which is indescribable, being not only unspeakable but even unthinkable. Difference or multiplicity is due to Maya. Maya is also as avidya, ajnana etc.

Adhyasa: It is self evident that the subject and the object are absolutely opposed to each other like light and darkness. The subject is pure consciousnes; the object is unconsciousness. The one is ultimate ‘I’ and the other is ‘non-I’. Neither these 2 nor their attribute can therefore be identified. Yet it is the natural and common practice of people that they wrongly superimpose the object and its attributes upon the subject and error, this coupling or real and unreal is called Superimposition or Adhyasa or illusion or maya. The study of vedanta is undertaken in order to free oneself from this false notion of superimposition and there by realize the essential unity of the self.

Maya: Maya and avidya is pure illusion. It is not only absence of knowledge, it is also wrong knowledge. It is a cross of real and unreal. It is false or mithya. But it is not a non-entity like a hare’s horn. It is positive. It is potency (shakti). It is called superimposition. A shell is mistaken as silver. The shell is the ground on which silver is superimposed. When right knowledge arises this error vanishes. The relation between shell and silver neither that of identity nor of difference nor of both. It is unique and is known as non-difference. Similarly, Brahman is the ground on which world appears through Maya. When right knowledge dawns and essential unity of jiva with paramatman is realized, Maya or Avidya vanishes.

There are total 108 Upanishads exist. But 10 are important and authentic on which shankracharya has commented. These are:

1. Ishavasyopnishad
2. Kenopnishad
3. Kathopnishad
4. Prashnopnishad
5. Mundkopnishad
6. Mandukyapnishad
7. Taittariyopnishad
8. Aitariyopnishad
9. Chandogyapnishad
10. Brhadaranyakopnishad

Prastanatarya & Teachings of Shankara

Sankracharya the 8th century philosopher, and commentator of prastanatrya – a combination of 3 scriptures (Brahma sutra, Bhagvad Gita and Upanishad), was great teacher and systematic propunder of Advait Vedanta Philosophy. Ultimate reality according to Shankra is Atman or Brahman which is pure consciousness. Brahman associated with its potency maya appear as a qualified Brahman who is the creator of the world. Jiva or individual self is a subject object complex. Avidya is the root cause of individuality. In liberation avidya is destroyed by janana and jiva is realized as the Brahman which is eternal.

Sankracharya emphasizes that from the phenomenal point of view the world is quite real, it is not ilusion. The world is real until the true knowledge of the world is not drawn, that is Brahma Satyam jagat Mithya Jivo Brahmaiva naparah, that means, Brahman is only reality, the world is ultimately false, the individual soul is not different from Brahman. These are the summary of Shankara’s teachings. This oneness of Jiva and Brahman can be attained by manana of the upanishads.