The Mimamsa is a system of enquiry and interpretation of meaning, rather the meaning of meaning. The Mimamsa is especially known as Purvamimamsa, or the earlier Mimamsa, to distinguish it from the Uttaramimamsa or the later Mimamsa, known also as the Vedanta.

The Mimamsa establishes the authority of the Veda, and makes out that its purport is ritual, on account of which it is also known as Karma-mimamsa. The system bases itself on the Brahmana portion of the Vedas which interprets the scripture ritualistically, as also on the Srauta Sutras which expatiate on the methods of ritual. Philosophically, in its essential outlook of life, the doctrine is similar to the Nyaya and the Vaiseshika empiricism. The Brahmanas are texts which are attached to each of the four Vedas, and they rationalise the ritualistic trend in religious performance.

The supreme authority for the Mimamsa is verbal testimony (Sabda-Pramana) on the basis of which principle the Veda is regarded as without any human author (Apaurusheya) and as eternal by itself. The Eternity of the Veda is proved by the semantic relation obtaining between a word and its meaning, which relation is said to be a permanent one. The letters which form a word are impartite compounds and, hence, imperishable. A letter as uttered or articulated is different from the mode of its utterance. Here comes in the speciality of the Veda Mantra which cannot be pronounced as one likes, and its meaning consists in the mode or the tone (Svara) in which it is uttered or chanted. A word is an aggregate of letters with a location of their linguistic position in a sentence, but the meanings expressed by the words are universal in their nature. The relation between the word and its meaning, thus, is eternal.

However, it does not follow from the above that all literature is also eternal. The speciality of the Veda is that the sequence or order in which the words are arranged is permanent and unchangeable and cannot be modified by any human agent. That is, the Veda cannot be edited or improved upon by anyone, since it is by itself an eternally established body of knowledge requiring no emendation. The Veda has intrinsic validity and is not based on extrinsic factors; that is, it is unconditioned. The knowledge of the Veda is faultless and is free from the defects which may enter into ordinary speech or language. The sphere of the Veda is a super-sensible realm of realities, while the process of perception, etc., has as its field empirical reality. The Mimamsa system has an elaborate technique of determining the definite rules that are to be followed in the correct interpretation of the Veda, so that its real meaning may be ascertained.

The Veda teaches Dharma, which the Mimamsa defines as religious duty in the form of do's and don'ts in the field of action or duty. There are permanent obligations (Nitya Karmas), occasional obligations (Naimittika Karmas), optional performances (Kamya Karmas) and prohibited actions (Nishiddha Karmas). While the first two kinds of action are imperative and are incumbent upon everyone as duty in the proper sense of the term, they do not bring any merit, but their non-performance brings demerit. The third category does bring merit when performed but does not bring demerit when not performed. It is the fourth variety that does not come under duty. Prohibited actions are those that bring ruin to a person and, to society, incidentally.

The Mimamsa takes this pain of explanation and interpretation to establish finally the validity of the performance of sacrifices according to the injunctions of the Brahmana texts, in order that the performer may reach heaven. But, how can sacrifice which has an end take one to heaven after death? The Mimamsa establishes a relation between the sacrifice and the joys of heaven by the proposition that the sacrificial action produces an invisible and subtle potency which does not perish with the deed but continues to exist as a potential force, known as Apurva, until its fruit is reaped. The Apurva, thus, acts as a bridge between the sacrifice performed here and the experience of heaven afterwards. The aim of the Mimamsa is attainment of heaven (Svarga), the abode of the gods who are eulogised through the Veda Mantras and propitiated through sacrifices performed by the application of the requisite Mantras or formulae for the invocation of the divinities.

The purpose of the Mimamsa is to prescribe details of what is yet to be achieved in the future through performance of works, and not to assert what already exists. Here the Mimamsa and the Vedanta are poles apart.