Indian philosophy on spirituality is intricately much deeper and rich than anywhere else. The strong roots have not only been preserved by the Indian culture and traditions since thousands of years, but have also spread to the western nations. It is based on this ideology that conception of Hatha yoga has taken place. And since Hatha yoga has developed post Vedic, it is important to place yoga within the context of Indian philosophy. To know hatha we have to understand at least some of the theoretical themes that underly the practical endeavour of yoga. This elaborate theme is embedded in Indian philosophy or "Darshanas" (viewpoints or systems). To understand the relation with Hatha Yoga, particular attention is required for the classical Yoga darsana of Patanjali and its relevance to hatha-yoga.

The Six Astika Darshanas
Vedic Samhitas may be seen as the roots the Indian philosophical tradition. The Brahmanas, Aranyakas and Upanishads may arise from that roots. Then followed the multiple philosophical `schools` in the post-Vedic era. Interestingly, the authority of these schools is derived from their adherence to the Vedic scriptures. Although, they all are secondary to the Vedas and Upanishads themselves, each major `school` is presented not in the form of a long and rigorously argued treatise but as a series of terse statements, known as sutras. Sutras are the coded medium to convey knowledge in different ways. The traditions of interpretation, which are based upon these texts, are known as Darshanas. Sutras, like shruti are believed to be verbal expressions of truth or realization.

Darshana denotes a system of philosophy, or doctrine in the sense of a treatise or an enquiry into truth or reality. There exist a semantic distinction between darsana and darsana Shastra. The Indian philosophers consider philosophy both as darsana, the vision of truth; and darsana-shastra, the means to attain it. There are six principal Astika or Vaidika darsanas, which embody the firm conviction in Veda. Apart from that are Darsanas called Nastika (`non-orthodox`) or Vedavahya (`outside the Veda`), which do not explicitly align them with the belief that the Vedas are infallible, revealed documents. The Six Astika Darshanas are:
1. The Vaisesika darshana, founded upon the Vaisesika-Sutra of Kanda.
2. The Nyaya darsana, founded upon the Nyaya-Sutra of Gautama.
3. The Samkhya darsana, founded upon the Samkhya-Sutra of Kapila.
4. The Yoga Darshana, founded upon the Yoga-Sutra of Patanjali.
5. The Purva-mimansa Darshanas, founded upon the Mimamsa-Sutra of jaimini.
6. The Uttara-Mimansa or Vedanta darsana, founded upon the Vedanta-Sutra (or Brahma-Sutra) of Badarayana.

Hatha-yoga (a part of Saiva tradition) views itself as being thoroughly Vaidika. This fact is something, which is implicit within the general philosophy of the hatha treatises, and even more explicit in the codes of ethical conducts as prerequisite for the yoga. The interpretation of these Sutras is difficult task in itself due to the extremely complex format of sutras where by the maximum amount of meaning is condensed into the minimum number of words. Each word and phrase contains various possible interpretations. The Darshanas have a tremendous amount in common and they are all directed towards a "goal of human liberation or Self-realisation". The intra and inter conflicts between various Darshanas can be regarded as the subjective choice available for the person or seeker.

Indian philosophy is much deeper rather than "the knowledge for the knowledge sake." The philosophical enterprise here acts as a method for cultivating virtue and self-understanding. It is for this reason that, Indian philosophical systems or Darshanas may be referred as Moksha-shastra. Moksha means `deliverance`, `release` or liberation` and shastra is the `teaching` or `doctrine` for achieving that end.