Orthodox (astika) schools of Indian Philosophy, originally known as Sanatana dharma, are now collectively referred to as Hinduism. Their source and scriptural authority are the ancient Vedas. Hinduism is divided into six philosophical and theological systems. Almost all Indian schools of thought accepted the theory of karma and rebirth, and the ideal of moksha is defined as freedom from the cycle of births and deaths. Moksha/liberation is regarded as the ultimate goal of human struggle. Here we will discuss the features of Orthodox schools and their different sub-schools, which will be helpful in UPSC CSE preparation.

Orthodox School

• It is also known as Astika school.
• The Vedas, according to this school, are the greatest revealed scriptures that contain the keys of salvation.
• They had no doubts about the Vedas' authenticity.
• They had six sub-schools, called Shada Darshana - such as Samkhya, Yoga, Nyaya, Vaisheshika, Mimamsa, and Vedanta.

Samkhya School

• The earliest of all the philosophies proposed by the philosopher Kapil Muni in Samkhya Sutra.
• 'Samkhya' or 'Sankhya' translates to 'count'.
• This school went through two stages of development: Original Samkhya View and new Samkhya View.
• This school believed in dualism or dvaitavada, which means that the soul and matter are separate entities. This concept is the foundation of all true knowledge.
• Purusha (soul) and Prakriti (nature) are both present in this dualistic worldview.
• Sankhya School is the foundation of Advaita Vedanta and also the philosophical foundation for Yoga.
• It stresses the use of meditation and focuses to gain self-awareness.

*For detailed notes of this topic, check this link Samkhya School

Yoga School

• Yoga school teaches the ways of the body and mental discipline.
• Yoga was founded by Sage Patanjali.
• The Yogasutra of Patanjali, which is tentatively dated to the second century BCE, elaborates on the origins of Yoga and the school.
• Yoga is the notion of emancipation of Purusha from Prakriti via self-awareness and body-mind discipline.
• Practicing Ashtanga Yoga is said to be a technique of purging oneself of previous transgressions to make room for freedom.

*For detailed notes of this topic, check this link Yoga School

Nyaya School

• Nyaya School takes a scientific and reasonable approach to learning.
• This school was founded by Sage Gautama who is also the author of Nyaya Sutra.
• The Nyaya school relies on several pramanas (mechanism of attaining knowledge).
• It believes that the only way to break free from the cycle of life and death is to achieve knowledge through the five senses.

*For detailed notes of this topic, check this link Nyaya School

Vaisheshika School

• The Vaisheshika school of thought believes in the physicality of the universe and is regarded as the realistic and objective philosophy that governs it.
• The Kanada, who also wrote the basic text governing the Vaisheshika philosophy, is widely regarded as the school's founder.
• They contend that the five primary elements, fire, air, water, earth, and ether (sky), created everything in the universe. These material elements are also referred to as Dravya.
• They also argue that reality is divided into many categories, such as action, attribute, genus, inherence, substance, and distinct quality.
• Because of this school's scientific approach, they also developed the atomic theory, which states that all material objects are made of atoms.

*For detailed notes of this topic, check this link Vaisheshika School

Mimamsa School

• Mimamsa means "the art of reasoning, interpretation, and application."
• This school focuses on the analysis of Samhita and Brahmana texts, which are parts of the Vedas.
• They contend that the Vedas are the repository of all knowledge and contain eternal truth.
• If one wishes to obtain religious merit, heaven, and salvation, one must perform all of the duties prescribed by the Vedas.
• The Sutras of Jaimini, which were allegedly written in the third century BCE, are the texts that describe the Mimamsa philosophy in detail.
• Two of their most ardent supporters, Sabar Swami and Kumarila Bhatta, made further inroads into the philosophy.

*For detailed notes of this topic, check this link Mimamsa School

Vedanta School

• Vedanta is made up of two words: 'Veda' and 'ant,' which refers to the conclusion of the Vedas.
• This school adheres to the life philosophies elucidated in the Upanishads.
• The oldest text that served as the foundation for this philosophy was the Brahmasutra of Badrayana, which was written and compiled in the second century BCE.
• According to the philosophy, Brahma is the reality of life and everything else is unreal or Maya.
• Furthermore, the Atma, or self-consciousness, is related to the Brahma. This argument equalizes Atma and Brahma, and if a person achieves self-knowledge, he will automatically understand Brahma and achieve salvation.
• Shankaracharya's Advaita, Ramanujacharya's Vishishta Advaita, and Madhwacharya's Dvaita are the three sub-branches of Vedanta.
• The Upanishads are the foundation of Uttara Mimamsa or Vedanta (the end portions of Vedas).

*For detailed notes of this topic, check this link Vedanta School

Conclusion

Orthodox schools acknowledge the Vedas' authority, whilst heterodox schools do not. Sankhya, Yoga, Nyaya, Vaisheshik, Mimansa, and Vedanta are the six orthodox schools (shatdarshan). The doctrine of karma and reincarnation was embraced by almost all Indian schools of thought, and the goal of moksha was understood as freedom from the cycle of births and deaths. The greatest objective of human effort is moksha (freedom).