The great Rishis, settled in the peaceful, invigorating environment of the forests, meditated over the fundamental questions of existence: What is the world? If it’s a creation, what are its constituents? Who is the creator? What is life? What is ‘truth’? What is ‘the nature of reality’?

What was revealed to them was expressed in hymns. With the passage of time, the systematized collection of these hymns constituted the Vedas and the Upanishads.

The Vedas are the oldest scriptures in the world. The Indian philosophical systems are classified according as they accept the authority of the Vedas or not. The systems of Indian philosophy are classified into two groups:

(1) The Orthodox Systems

(2) The Unorthodox Systems

 The orthodox systems are: Vaisheshika, Nyaya, Samkhya, Yoga, Purva-Mimamsa, and Uttar-Mimamsa.

The unorthodox systems are: Charvakism, Jainism and Buddhism.

 Very often, Purva-Mimamsa is referred to as “Mimamsa” only and Uttar-Mimamsa as “Vedanta”.

 The orthodox systems uphold the supremacy of the Vedas. The unorthodox systems reject the authority of the Vedas. Truly speaking Vaisheshika, Nyaya, Samkhya and Yoga are neither orthodox nor unorthodox. These four systems, while originating, neither accepted nor rejected the Vedas.

The orthodox systems form pairs as follows:

Nyaya-Vaisheshika, Yoga-Samkhya, Mimamsa-Vedanta. In each of the pairs, the first system is concerned with the practice and the second system focuses on the theoretical aspects.

The following characteristics are common to all systems: 

(1) All the schools emphasize that the philosophy must have a positive impact on life of man. The schools have a general agreement on the importance of the Purushartha.  All the schools agree that the philosophy should help man in realizing the main ends of human life: the purusharthas, i.e. artha, kama, dharma and moksha. (2) All the systems reflect that the philosophy should lead a man from darkness and ignorance to light and knowledge. (3) There is a general agreement among the systems that the truth and reality should be verifiable. They should be substantiated with reasoning and experience. An experience may be sensory, conceptual or intuitional. (4) It is accepted by all the schools that man’s suffering results from his ignorance. Man can conquer ignorance and attain total freedom (moksha) in this bodily existence.  (5) There is a general agreement on man’s essential spirituality.

The first major orthodox philosophical system to develop was Purva Mimamsa. The other one to follow was the Uttar Mimamsa. The orthodox systems accept the authority of the Vedas.