In ancient India what we now call a philosophy was termed a view (skt darshan). This is in contrast to the western tradition where philosophy can be more doctrinaire in its approach. The Indian intellectual tradition is relativist, any philosophy is a point of view, correct only on the basis of a set of presuppositions. The six most important views were, according to one important text said to be:
Nyaya or the logical school;
Its close relative the school of Vaisheshika or Atomism;
Mimamsa, literally 'enquiry', a school dedicated to the defence of the authenticity of the Vedas;
The Vedanta non-dualist school;
The Samkhya or Reasoning School.
Samkhya is widely believed to be one of the oldest of the six and along with the Vaisheshika Atomic school the main influence on the medico-scientific (Ayurveda) tradition and Tantrism. Samkhya represents an extremely important philosophical tendency in Indian thought. All of the later philosophies defined themselves in relation to its theories, either for them or against.
In reality there were many more than six philosophies in India. One important view was preserved by the Raseshvara (mercury lords), ranked as about eighth in an imaginary league table of important views.(2) This system almost certainly comprises alchemical practitioners like Nagarjuna and is closely akin to the later Tantrik and Ayurvedic views. It is worth noting that ideas connected with medical science (Ayurveda) are also extremely pervasive and very authoritative. In fact, there is hardly any text in the Indian intellectual tradition from the Late Upanishads onwards that does not make some reference either directly or otherwise, to Ayurveda.
continued at samkhya