The six systems of Indian philosophy are Nyaya, Vasiseshika, Sankhya, Yoga, Purva Mimamsa and Uttara Mimamsa. Each of these systems differs in one way or the other in terms of its concepts, phenomena, laws and dogmas. Each system has it’s own founder as well. It is important to know that the founders of these systems of philosophy are sages of the highest order that have devoted their lives for the study and propagation of philosophy. Each system of Indian philosophy is called a Darshana. Thus the Sanskrit word ‘Shad-Darshana’ refers to ‘the six systems of philosophy’.
The founder of the Nyaya system of philosophy is Gautama. Nyaya belongs to the category of Astika Darshanas. It is important to know that Astika Darshanas realize the significance of verbal testimony or the authority of the Vedas. Gautama is thought to have lived during the middle 5th century, BC. He is also called Akshapada.
All six systems of philosophy lay equal importance to “valid means of acquiring knowledge” called the ‘Pramanas’. Gautama was the first philosopher to stress the importance of the valid means of knowledge and hence the Nyaya system of philosophy is said to have laid the firm foundation to the development of the science of Hindu logic. Gautama’s Nyaya system of philosophy is also called by names such as Nyaya Sastra and Tarka Sastra.
The philosophical system of Nyaya accepts four Pramanas or valid means of acquiring knowledge. They are Pratyaksha (perception), Anumama (inference), Upamana (comparison) and Shabda (verbal testimony). Nyaya, like many other systems of philosophy aims at the attainment of liberation. According to them the attainment of Moksha which they call ‘Apavarga’ is the highest goal of human life. The attainment of Apavarga brings about the end of all the sufferings of human life. Nyaya Darshana accepts the existence of God. They call Him ‘Ishwara’ and say that He is the cause for the creation of the universe. He alone sustains it and destroys it as well. One of the most important views put forth by Gautama is about the theory of creation. According to him the universe is created by God with the help of the eternal atoms, time, individual minds, space and individual souls or jivas and ether. He does not create the universe out of Himself as pointed out by the other later systems of philosophy.
The founder of the Vaiseshika system of Indian philosophy is Kanada or Uluka. Hence it is also called Aulukya Darshana. It is important to know that the Vaiseshika system followed the Nyaya system very closely and hence experts in the study of philosophy often combine the two schools as Nyaya-Vaiseshika. The Vaiseshika system recognizes seven ‘Padarthas’ or categories which are: are substance, quality, action, generality, particularity, relation of inherence and non-existence. The followers of this system of philosophy also accept the existence of God and they say that He created, sustained and destroyed the universe. According to the Vaiseshika School of philosophy, the will of God is the cause for creation. Brahma is the very first product of the will of God and He does the second part of creation according to the merits and the demerits of the individual souls. He causes the combination of the moving atoms and thus is instrumental in the creation of the world. At the time of the dissolution of the universe the entire world is reduced to the primary state of the seven categories.
Sage Kapila founded the Sankhya system of philosophy. In fact it can be said that the Sankhya system laid the firm foundation for the Advaita Vedanta later on. Swami Vivekananda once said that the Vedanta system of Advaita owed a lot to Sage Kapila, the founder of the Sankhya system of philosophy. The dogmas put forth by Kapila were further expounded by his disciples Asuri and Panchashikha. The Sankhya Sutras compiled by Kapila were commented on later by Ishvara Krishna of the 5th Century AD. It is interesting to note that the Sankhya system accepts only three Pramanas or the valid means of acquiring knowledge. They accept Pratyaksha or perception, Anumana or inference and Shabda or verbal testimony. They don’t accept Upamana or comparison. Sankhaya accepts only two realities, namely, the Prakriti or the insentient nature and the Purusha or the soul. These two are eternal according to Kapila. According to the Sankhya system of philosophy, something can never be produced out of nothing. One can see the influence of the Nyaya system on the Sankhya system when it comes to the process of creation. Pleasure, pain and indifference are derived by the three ‘gunas’ or ‘qualities’, namely, Sattvaguna, Rajoguna and Tamoguna. Sattva guna gives rise to happiness or pleasure, Rajoguna produced pain and suffering whereas Tamoguna gives rise to inactivity.
The three qualities mentioned above reside in the Prakriti, a state of perfect balance. Kapila says that the entire universe is born out of the Prakriti or the primordial matter. Purusha on the other hand is as innumerable as there are living beings. Purusha is all-pervading and eternal. He is consciousness in its very essence. Sankhya believes in the creation of the universe as a result of the union between Prakriti and Purusha. Kapila describes an interesting process of evolution of the world. The very first evolute that issues forth from the Prakriti by the combination of the three gunas is the Mahat or the cosmic intellect. Cosmic ego is born out of the cosmic intellect. There are various evolutes issuing forth from the different parts of the cosmic ego characterized by the gunas. The mind, the five organs of knowledge like the eyes and the ears, the five cosmic organs of action like the hands and the feet and the five subtle elements like the water and earth. From the five subtle elements are born the five gross elements or Pancha Mahabhutas called earth, water, fire, air and ether. Thus 24 evolutes issue forth from Prakriti or the primordial matter. They are called 24 cosmic principles. According to the Sankhya system of philosophy, a dead person will not return back to the mortal world since he attains ‘Videhamukti’ a state of final liberation.
The Yoga system of philosophy was founded by Patanjali. He authored the Yoga Sutras or the aphorisms of Yoga. The date is not clearly known but his work is of great value to the seekers of the state of spiritual absorption. Yoga aims at the final state of spiritual absorption through eight component parts, together called Ashtanga Yoga. The eight limbs of Yoga according to Patanjali are Yama, Niyama, Asana, Pranayama, Pratyahara, Dharana, Dhyana and Samadhi. All the eight are jointly called Raja Yoga. Yama aims at internal purification, Niyama aims at external purity, Asana consists in the performance of the postures of Yoga, Pranayama is breath control, Pratyahara results from the withdrawal of sense organs from the corresponding sense objects, Dharana is concentration, Dhyana is meditation and Samadhi is the final state of spiritual absorption.
The Yoga system of philosophy accepts three fundamental realities, namely, Ishwara, Purusha and Prakriti or the primordial matter. Patanjali says that scriptures are the sources of the existence of Ishwara. Ishwara is omniscient and is free from the qualities inherent in Prakriti. Patanjali defines Yoga as ‘Chittavriitinirodha’. Yoga is the restraint of the mental operations. Patanjali names some obstacles to the path of Yoga. They are called ‘Antarayas’ and they include Vyadhi (illness), styana (apathy), Samsaya (doubt), Pramada (inadvertence), Alasya (laziness), Avirati (incontinence), Bhrantidarshana (wrong understanding), Alabdha Bhumikatva (non-attainment of mental plane) and Anavasthitatva (instability). In addition to the obstacles mentioned above, Patanjali accepts five more obstacles called Dukha (pain), Daurmanasya (frustration, Angamejayatva (fickle limbs), Svasa (spasmodic breathing in) and Prasvasa (spasmodic breathing out). Patanjali speaks about Jatyantara Parinama or the phenomenon of the evolution of one species or genus into another species or genus.
The philosophical system of Purva Mimamsa was founded by Jaimini. The Mimamsa Darshana believes firmly in the performance of rituals and supports the view that the body is perishable but the soul survives even after the death of the body and it reserves the right to enjoy the fruits of the rituals in heaven. The school firmly believes in the preservation of the effect or the fruits of the rituals by a remarkable power. It believes that the Vedas are impeccable in what they say. It does not talk about the Brahman or the Supreme Entity but says that the world is real. Mimamsa strictly is of the opinion that whatever we do in our life are not dreams or illusion but are real.
Jaimini accepts two types of knowledge, namely, Pratyaksha (immediate knowledge) and Paroksha (mediate knowledge). Paroksha Jnana is of five kinds, namely Anumana (inference), Upamana (comparison), Shabda (verbal testimony), Arthapatti (postulation) and Anupalabdhi (non-perception). Jaimini accepts the plurality of souls. He says that the souls are eternal but they definitely undergo transmigration as according to the actions performed by the bodies. Liberation is considered the highest good for humanity. Liberation puts an end to the transmigration of the soul. Performance of the daily duties brings about liberation. On the other hand the non-performance of actions or daily duties causes disruption in the path of liberation. One of the most important observations made by the Purva Mimamsa system of philosophy is that there is no need for the existence of God to create the world. This is because of the fact that all the material needed for the formation and the creation of the world are available eternally. Hence Mimamsa does not speak about the existence of God. Performance of daily duties or the Nitya Karmas is the ultimate goal of man.
The philosophical system of Uttara Mimamsa does not have a specific founder since it is a conglomeration of three different schools of thought, namely Advaita, Visishtadvaita and Dvaita. The philosophical system of Utttara Mimamsa is otherwise called Vedanta. All the three schools of Vedanta have different teachers. Adi Sankara is the head of the Advaita system of Vedanta philosophy. Ramanuja is the architect of the Visishtadvaita system of Vedanta and Madhva is the head of the Dvaita system of Vedanta philosophy.
Adi Sankara is the first philosopher who identified the philosophical truths expounded in the Upanishads attached to the Vedas. Jaimini gave importance to the Karma Kanda portion of the Veda whereas Sankara saw the Supreme Truth that lay firm in the message of the Upanishads. Sankara called the world illusory as a result of Maya or delusion. Maya causes the illusion akin to the cognition of serpent on the rope. A person gripped by ignorance fails to see the substratum of the universe. Brahman is the substratum of the universe. It is not seen due to delusion or Maya. Sankara calls the universe an illusion and the Brahman or the Supreme Entity as Truth. Everything around us is adventitious of the Brahman. Into Brahman all creation goes. Deluge is the ultimate condition during which the Brahman withdraws all its creation unto itself.
Ramanuja advocated the Visishtadvaita school of Vedantic thought. It is a qualified version of monism and hence is called qualified monism. Ramanuja differs from Sankara only a little in the sense that he considers the jiva or the individual soul as the entity different from the body and is infinite in number and cannot be one with the Supreme as long as it is confined in a body. Madhva the founder of the Dvaita school of Vedantic thought says that the jivas or the souls can attain liberation through bhakti and the grace of God. It is important to note that all the three teachers accepted Vedas as a valid means of knowledge.