Basics of Indian Philosophy

Basic Indian philosophy can be divided into two classes: astika and nastika.

The astika systems respect the ancient Vedas (the oldest sacred texts of Hinduism) as their source and scriptural authority, whereas the nastika systems of Jainism, Buddhism, and Lokayata, reject Vedic thought, literally meaning not astika.

Shad-Darshana

Six Systems of Philosophy

The six orthodox schools of the astika system, Samkhya, Yoga, Vedanta, Mimamsa, Nyaya, and Vaisheshika, were codified during the medieval period of Brahmanic-Sanskritic scholasticism. These schools are outlined in the Vedas as well as the Bhagavad Gita.

Samkhya:

Founder: Sage Kapila / Ishvarakrishna
Samkhya is the oldest of the orthodox philosophical systems.
Philosophy: Everything in reality stems from purusha (self or soul or mind) and prakriti (matter, creative agency, energy). It is a dualist philosophy, between the self and matter, and liberation occurs with the realization that the soul and the dispositions of matter (steadiness, activity and dullness) are different.
The Samkhya school assumes the existence of two bodies, a temporal body and a body of “subtle” matter that persists after biological death. When the former body has perished, the latter migrates to another temporal body.

Yoga:

Founder: Patanjali in his 2nd Century B.C. Yoga Sutras
Philosophy: Yoga accepts the Samkhya psychology and metaphysics, but is more theistic, with the addition of a divine entity to Samkhya's twenty-five elements of reality. The relatively brief Yoga Sutras are divided into eight ashtanga (limbs), reminiscent of Buddhism's Noble Eightfold Path, the goal being to quiet one's mind and achieve kaivalya (solitariness or detachment).

Nyaya:

Founder: Aksapada Gautama in the 2nd Century B.C.
Philosophy: The Nyaya school is based on the Nyaya Sutras, a system of logic that has subsequently been adopted by the majority of the Indian schools, in much the same way as Aristotelian logic has influenced Western philosophy. Its followers believe that obtaining valid knowledge (the four sources of which are perception, inference, comparison and testimony) is the only way to gain release from suffering.

Vaisheshika:

Founder: Kanada in the 6th Century B.C.
Philosophy: The Vaisheshika school is atomist and pluralist in nature. The basis of the school's philosophy is that all objects in the physical universe are reducible to a finite number of atoms, and Brahman is regarded as the fundamental force that causes consciousness in these atoms. The Vaisheshika and Nyaya schools eventually merged because of their closely related metaphysical theories (although Vaisheshika only accepted perception and inference as sources of valid knowledge).

Mimamsa:

Philosophy: The main objective of the Purva Mimamsa school is to interpret and establish the authority of the Vedas. It requires unquestionable faith in the Vedas and the regular performance of the Vedic fire-sacrifices to sustain all the activity of the universe. Although in general the Mimamsa accept the logical and philosophical teachings of the other schools, they insist that salvation can only be attained by acting in accordance with the prescriptions of the Vedas. The school later shifted its views and began to teach the doctrines of Brahman and freedom, allowing for the release or escape of the soul from its constraints through enlightened activity.

Uttara Mimamsa:

Founder: The philosophical system of Uttara Mimamsa does not have a specific founder since it is a conglomeration of three different schools of thought (Advaita, Visishtadvaita and Dvaita)
Philosophy: The Uttara Mimamsa school concentrates on the philosophical teachings of the Upanishads (mystic or spiritual contemplations within the Vedas), rather than the Brahmanas (instructions for ritual and sacrifice). The Vedanta focus on meditation, self-discipline and spiritual connectivity, more than traditional ritualism.

"The principles of the Bhagavad-gita were spoken to Arjuna, and, for that matter, to other highly elevated persons, because he was highly advanced compared to ordinary persons in other parts of the world. Two plus two equals four is a mathematical principle that is true both in the beginner's arithmetic class and in the advanced class as well. Still, there are higher and lower mathematics. In all incarnations of the Lord, therefore, the same principles are taught, but they appear to be higher and lower in varied circumstances. The higher principles of religion begin with the acceptance of the four orders and the four statuses of social life, as will be explained later." (asitis.com)

Sources

Books:

Eknath, Easwaran. The Bhagavad Gita. Petaluma, CA: Nilgiri Press, 1985. Print.

Websites:

http://www.philosophybasics.com/

http://muneshkumarkella.blogspot.com/2013/09/shad-darshan-darshan-shastra-six-school.html

http://www.uwyo.edu/religionet/er/hinduism/htexts.htm

http://www.hinduwebsite.com/24principles.asp

https://www.britannica.com/biography/Kapila

https://yogaforums.com/t/the-six-systems-of-indian-philosophy/7255

https://www.britannica.com/topic/Samkhya

https://www.asitis.com/