Rationality in Classical India philosophy is considered as a vital concept. It would be wrong to state that this concept is marginal or absent from the wide array of the traditions of Indian classical philosophy. The concept of cultural notion is stated to be rational. It is embedded, articulated and manifested in culturally specific ways. The role of a concept of rationality within a culture is a highly stratified one, its criteria and principles operating first of all in the life-world of the community concerned, then in the higher-order decisions of the scientists, law-givers and artists, finally in the theoretical discourse of the philosophers. New paradigms of what it is to act and believe rationally come into being as old concepts are criticised, revised and rejected. Forms of rationality are inter-culturally available even if they are not always inter-culturally observed.

In analysing the rationality in Indian classical philosophical literature, scholars adopt an approach that is neither comparative nor historical. According to them, Philosophy is not history, even if both disciplines are relevant to the study of classical India. History studies ideas in their context - it situates an author in an intellectual milieu. Philosophy, on the other hand, tries to free an idea from its context - it separates the idea from what is narrow-minded and contingent in its formulation. The historian of Indian philosophy is sensitive to the character of a philosophical thesis, though does not indulge in wanton borrowing from other philosophical literatures. Like for instance, Kautilya`s conception of rationality is goal-oriented and instrumental. The interest is in the reasoned way to achieve some goal, whatever that goal may be.

Reason is the instrument of all philosophers, but conceptions of the nature and function of reason vary along with varying ideas about the work for which reason is properly employed. Scholars of philosophical concept reveal that a diachronic study of conceptions about what constitutes an adequate resolution to a moral dilemma illuminates both shifts in the notion of reason itself, and also the mechanics of internal criticism, theory revision and paradigm rejection. Reason can be used or abused. A cautionary episode in the Mahabharata illustrates the point. Bhishma tells Yudhisthir that there is nothing more worth having than wisdom. Wisdom, he declares, is the greatest good, the refuge of all living things, the ultimate acquisition, and is considered by the virtuous to be heaven itself.