Hinduism has six different schools of philosophy:
- Purva-mimamsa and
- Uttara-mimamsa (also called Vedanta)
Of these schools of philosophy, the most popular one is Vedanta, within which, the following sub-groups are predominant:
- Advaita (Monism) by Adi Shankara
- Vishistadvaita (Qualified monism) by Ramanujacharya
- Dvaita (Dualism) by Madhvacharya
- Achintya Bhedabheda (Inconceivable oneness and difference) by Krishna Chaitanya
Samkhya is widely regarded to be the oldest of the orthodox philosophical systems in Hinduism. Its philosophy regards the universe as consisting of two eternal realities: purusha and prakrti. The purushas (souls) are many, conscious and devoid of all qualities. They are the silent spectators of prakrti (matter or nature), which is composed of three gunas (dispositions): satva, rajas and tamas (steadiness, activity and dullness). When the equilibrium of the gunas is disturbed, the world order evolves. This disturbance is due to the proximity of Purusha and prakrti. Liberation (kaivalya), then, consists of the realisation of the difference between the two.
This was a dualistic philosophy. But there are differences between the Samkhya and Western forms of dualism. In the West, the fundamental distinction is between mind and body. In Samkhya, however, it is between the self (purusha) and matter, and the latter incorporates what Westerners would normally refer to as 'mind'.
The Nyaya school of philosophical speculation is based on a text called the Nyaya Sutra. It was written by Gautama (not to be confused with the founder of Buddhism), also known as Akshapada, round about the fourth or fifth century B.C. The most important contribution made by this school is its methodology. This is based on a system of logic that has subsequently been adopted by most of the other Indian schools (orthodox or not), much in the same way that Western science, religion and philosophy can be said to be largely based on Aristotelian logic.
But Nyaya is not merely logic for its own sake. Its followers believed that obtaining valid knowledge was the only way to obtain release from suffering. They therefore took great pains to identify valid sources of knowledge and to distinguish these from mere false opinions. According to the Nyaya school, there are exactly four sources of knowledge (pramanas): perception, inference, comparison and testimony. Knowledge obtained through each of these can of course still be either valid or invalid, and the Nyaya scholars again went to great pains to identify, in each case, what it took to make knowledge valid, in the process coming up with a number of explanatory schemes. In this sense, Nyaya is probably the closest Indian equivalent to contemporary Western analytical philosophy. An important later development in Nyaya is the system of Navya Nyaya (New Logic).
The Vaisheshika system, which was founded by the sage Kanada, postulates an atomic pluralism. In terms of this school of thought, all objects in the physical universe are reducible to a certain number of atoms.
Although the Vaishesika system developed independently from the Nyaya, the two eventually merged because of their closely related metaphysical theories.
In its classical form, however, the Vaishesika school differed from the Nyaya in one crucial respect: where Nyaya accepted four sources of valid knowledge, the Vaishesika accepted only perception and inference.
The Yoga system is generally considered to have arisen from the Samkhya philosophy. Its primary text is the Bhagavad Gita, which explores the four primary systems (see Bhagavad Gita); the sage Patanjali wrote an extremely influential text on Raja Yoga (or meditational) entitled the Yoga Sutra. The most significant difference from Samkhya is that the Yoga school not only incorporates the concept of Ishvara (a personal God) into its metaphysical worldview, which the Samkhya does not, but also upholds Ishvara as the ideal upon which to meditate. This is because Ishvara is the only aspect of purusha that has not become entangled with prakrti. It also utilizes the Brahman/Atman terminology and concepts that are found in depth in the Upanishads, thus breaking from the Samkhya school by adopting Vedantic monist concepts. The Yoga system lays down elaborate prescriptions for gradually gaining physical and mental control and mastery over the personal, body and mind, self, until one's consciousness has intensified sufficiently to allow awareness of one's real Self (the soul, or Atman) (as distinct from one's feelings, thoughts and actions). Realization of the goal of Yoga is known as moksha, nirvana and samadhi. They all speak to the realization of the Atman as being nothing other than the infinite Brahman. See Yoga for an in-depth look at its history.
The main objective of the Purva ("earlier") Mimamsa school was to establish the authority of the Vedas. Consequently this school's most valuable contribution to Hinduism was its formulation of the rules of Vedic interpretation. Its adherents believed that revelation must be proved by reasoning, that it should not be accepted blindly as dogma. In keeping with this belief, they laid great emphasis on dharma, which they understood as the performance of Vedic rituals. The Mimamsa accepted the logical and philosophical teachings of the other schools, but felt that these paid insufficient attention to right action. They believed that the other schools of thought, which pursued moksha (release) as their ultimate aim, were not completely free from desire and selfishness. In Hinduism, we are all illuminated under the light of god. When we have moksha, we believe that we become closer to god. According to the Mimamsa, the very striving for liberation stemmed from a selfish desire to be free. Only by acting in accordance with the prescriptions of the Vedas could one attain salvation (rather than liberation). At a later stage, however, the Mimamsa school changed its views in this regard and began to teach the doctrines of God and mukti (freedom). Its adherents then advocated the release or escape from the soul from its constraints through what was known as jnana (enlightened activity). While Mimamsa does not receive much scholarly attention these days, its influence can be felt in the life of the practising Hindu. All Hindu ritual, ceremony and religious law is influenced by it.
Uttara Mimamsa: The Three Schools of Vedanta
While the traditional Vedic 'karma kanda' (ritualistic components of religion) continued to be practiced as meditative and propitiatory rites gearing society (through the Brahmins) to Self-knowledge, more jnaan (knowledge/discrimination) centered understandings began to emerge, mystical streams of Vedic religion that focused on meditation, self-discipline and spiritual connectivity rather than more practical aspects of religion like rituals and rites. The more abstruse Vedanta (meaning literally the end of the Vedas) is the essence of the Vedas, encapsulated in the Upanishads which are commentaries on the four original books (Rig, Yajur, Sama and Atharva). Vedantic thought drew on Vedic cosmology, hymns and philosophy. The first Upanishad, the Brihadaranyaka, appeared as far back as 1500 BCE. While thirteen or so Upanishads are accepted as principal, over one hundred exist. The most influential Vedantic thought, based on the Upanishads, considers the consciousness of the Self - Jeevatma - to be continuous with and indistinguishable from the consciousness of the Supreme or Brahman - Paramatma .
The Upanishads are acknowledged by scholars and philosophers from both East and West, from Schrödinger, Thoreau and Emerson to Rabindranath Tagore, Mahatma Gandhi and Aurobindo Ghosh, to be superlatively beautiful in poetry and rich in philosophy. But they do not form one single set of writings. There are over a hundred Upanishads and they do not form a unified system. They are traditionally classed into twelve or thirteen primary Upanishads, most notably one of the largest and the first to be written down (approximately 1500 BCE) called the Brihadaranyaka Upanishad. Their systematisation into one coherent treatise was undertaken by Badarayana , in a work called the Vedanta Sutra, also known as Brahma Sutra .
The cryptic way in which the aphorisms of the Vedanta sutras are presented leaves the door wide open for a multitude of interpretations. This led to a proliferation of Vedanta schools. Each of these interprets the texts in its own way and has produced its own series of sub-commentaries - all claiming to be faithful to the original.
1. Monism: Advaita Vedanta
Advaita Vedanta is probably the best known of all Vedanta schools. Advaita literally means "not two"; thus this is what we refer to as a monistic (or non-dualistic) system, which emphasises oneness. Its first great consolidator was Shankara (788-820). Continuing the line of thought of some of the Upanishadic teachers, and also that of his own teacher Gaudapada , Shankara expounded the doctrine of Advaita - a nondualistic reality. By analysing the three states of experience (waking, dreaming and deep sleep) he exposed the relative nature of the world and established the supreme truth of the Advaita: the non-dual reality of Brahman in which atman (the individual soul) and brahman (the ultimate reality expressed in the trimurti) are identified absolutely. His theories were controversial from the start and some of his contemporaries accused him of teaching Buddhism while pretending to be a Hindu. However, many more see Adi Shankara drawing from the monist concepts that were visibly ingrained in formerly existing texts, those pre-dating Buddha, like the more abstuse sections of the Vedas as well as the older Upanishads, several of which are conservatively and thus reliably dated as far back as 1000 BCE, if not 1500 BCE.
Subsequent Vedantins debated whether the reality of Brahman was saguna (with attributes) or nirguna (without attributes). Belief in the concept of Saguna Brahman gave rise to a proliferation of devotional attitudes and more widespread worship of Vishnu and Shiva. Advaita Vedanta is strictly grounded in a belief that the ultimate truth is nirguna Brahman. The Vishistadvaita and Dvaita schools believed in an ultimately saguna Brahman.
2. Qualified Monism: Vishistadvaita Vedanta
Ramanuja (1040 - 1137) was the foremost proponent of the concept of Sriman Narayana as the supreme Brahman. He taught that Ultimate reality had three aspects: Ishvara (Vishnu), cit (soul) and acit (matter). Vishnu is the only independent reality, while souls and matter are dependent on God for their existence. Because of this qualification of Ultimate reality, Ramanuja's system is known as qualified non-dualism.
3. Dualism: Dvaita Vedanta
4. Synthesis: Acintya Bheda - Abheda Vedanta
Caitanya (1486-1534), a devotee of Krishna, proposed a synthesis between the monist and dualist philosophies by stating that the soul is equally distinct (bheda) and non-distinct (abheda) from god, and that this, although unthinkable (acintya), is experiencable in devotion.