Indian philosophy is very vast and diverse in its nature. Like the Plato and Socrates and Kant in west, India had its own stalwarts who created new frontier in human being’s understanding of themselves and the world.
While there are many different schools of thought in India, there are 6 major astika schools of philosophy.
The rationalism school with dualism and atheistic themes. Samkhya believes that there are only three ways of gaining knowledge. Pratyaksha (self experience through perception), Anumana (logical inference) and Shabda (authority from reliable sources). Moreover Samkhya believes in duality where the world comprises of Purusa (Conciousness) and Pakriti (matter). Life or Jiva is created when these two meet and fuse together. The purpose of life is liberation and it is achieved when a person achives perfect balance of the two. Liberation is achieved via knowledge and it is a sufficient for liberation.
Kapila Muni is considered as founder of this school of philosophy and he appears prominently in Shvetashvatar Upanishad.
Yoga is very closely knit with Samkhya philosophy and is one of the major schools of philosophy in Hinduism. Patanjali’s Yogasutra is the key text of this philosophy and he is also credited to have found this school. Just like Samkhya Yoga claims that there are 3 ways of gaining knowledge. However the key difference between Yoga an Samkhya is is the notion of personal yet inactive deity or Ishtadevata which a person may use to achieve liberation.
Unlike Samkhya where knowledge alone can liberate in Yoga there is a focus on personal practice and personal experience besides on knowledge. Yoga this is a form of personal mysticism than purely knowledge seeking.
This school of philosophy deals with formal logic. This school accepts 4 pramanas. Pratyaksha (perception), Anumana (inference), Upamana (analogy and comparison) and Shabda (reliable sources).It holds that human suffering results from mistakes/defects produced by activity under wrong knowledge (notions and ignorance). Moksha (liberation), it states, is gained through right knowledge. This premise led Nyaya to concern itself with epistemology, that is the reliable means to gain correct knowledge and to remove wrong notions. False knowledge is not merely ignorance to Naiyyayikas, it includes delusion. Correct knowledge is discovering and overcoming one’s delusions, and understanding true nature of soul, self and reality.
The epistemology of Vaiśeṣika school of Hinduism, like Buddhism, accepted only two reliable means to knowledge: perception and inference. Vaiśeṣika school and Buddhism both consider their respective scriptures as indisputable and valid means to knowledge, the difference being that the scriptures held to be a valid and reliable source by Vaiśeṣikas were the Vedas.
Vaisesika is a very unique philosophy that was perhaps the first the propose that the matter is formed from tiny undivisible particles called Parmanu (atoms) and all life experiences are essentially the result of interplay between the substance at the atomic level.
Sage Kanada is considered founder of this school of philosophy.
Mimansa literally means critical examination and is easily the broadest of all other philosophies. It has far too many sub schools that deal with issues from Dharma, Hermeneutics, study of language, spirituality etc.
Mimansa deals in realism and besides the 4 pramanas, Kumarilla Bhatt added the 5th pramana called anuplabdhi (absense as evidence of non existence) to it. Mimansa Sutra of Jaimini has been a major text of this philosophy.
Mīmāṃsā theorists decided that the evidence allegedly proving the existence of God was insufficient. They argue that there was no need to postulate a maker for the world, just as there was no need for an author to compose the Vedas or a God to validate the rituals. Mīmāṃsā argues that the Gods named in the Vedas have no existence apart from the mantras that speak their names. To that regard, the power of the mantras is what is seen as the power of Gods.
Dharma as understood by Pūrva Mīmāṃsā can be loosely translated into English as “virtue”, “morality” or “duty”. The Pūrva Mīmāṃsā school traces the source of the knowledge of dharma neither to sense-experience nor inference, but to verbal cognition (i.e. knowledge of words and meanings) according to Vedas. In this respect it is related to the Nyāya school, the latter, however, accepts only four sources of knowledge (pramāṇa) as valid.
Perhaps the most well known philosophical tradition of modern times, Vedanta is also known as Uttar-Mimansa. There are approximately 10 sub-schools all dealing with diverse ideas. Principal Upanishads, Bramhasutras and Geeta come under Vedanta.
All he sub-schools in Vedanta deal with three main components but may disagree on their interplay and importance. Brahman as the supreme reality, Atma as an individual soul and Prakriti as the real world consisting of matter.
Dvaita and Advaita philosophies are branches of Vedanta. In dwaita the interplay of Atman and Brahman is considered important but in Advaita everything is considered manifestation of Brahman.