As you know, Indian Philosophy has six systems, which are called: ‘Orthodox systems of Indian Philosophy’. All the six systems of Indian Philosophy, which are ‘orthodox’ accept Veda as ‘pramāṇa’, they accept the authority of the Veda, they accept that whatever is in Veda is what we are expounding, each one, although each one is quarrelling with the other, but each one claims that it is expounding what is in the Veda and the Upanishads.
There are two other philosophies in India, which do not accept the authority of the Veda: these are Buddhism and Jainism. But both of them accept spiritual experience: in that sense these two systems are in agreement with the other six systems, which also believe in spiritual experience. These two are called ‘heretic’ philosophies. Heretic means: those which oppose the authority of the Veda. There is another system, one more system; it is called ‘Charvaka system’ (cārvāka): it is a materialistic philosophy; it does not accept spiritual experience at all. It believes that human body and Matter is the only reality, and after the body is burnt away, after death, what remains? Nothing remains. Therefore it says that while you live, you try to gain maximum pleasure in the world: “You avoid water and drink ghee: jalaṃ tyaktvā ghṛtaṃ piba”. Because after the world the whole body is finished, what remains? Nothing remains. Can you see anything? All is gone.
Indian philosophy has got basically nine systems: six philosophies are ‘orthodox’, which all accept the Veda; two are ‘heretic’ philosophies which do not accept the authority of the Veda: they are Jainism and Buddhism, but both of them accept spiritual experience; Charvarka is a purely materialistic philosophy. In the entire History of India, there have been so many philosophers; they have belonged to one or the other of these nine philosophies.
These six systems of Indian philosophies are known as follows: Nyaya (nyāya), Vaisheshika (vaiśeṣika), Sankhya (sāṁkhya), Yoga (yoga), Purva Mimansa (pūrva mīmāṁsā), and Uttara Mimansa (uttara mīmāṁsā), which is also known as Vedanta (vedānta), Uttara Mimansa is also known as Vedanta. These are the six systems of Indian philosophy. Now, you will find that in this enumeration, there is one word ‘Yoga’ there. So, today if you speak of Yoga, people mean by that word ‘Yoga’, that philosophy, which is one of these six systems.
What is this system? And what does it expound? Let us take it very briefly, some of the basic propositions of this philosophy. It is Patanjali who is supposed to have formulated the aphorisms of this philosophy. Just as Gautama is supposed to have formulated the aphorisms of Nyaya, Kanada of Vaisheshika, Kapila of Sankhya, Patanjali of Yoga, Jaimini for Purva Mimansa, and Bādarāyaṇa for Uttara Mimansa. These are the basic philosophers, you might say, who gave the formulation in aphoristic forms. It is a very peculiarity of Indian philosophy that basic texts of Indian philosophy are in aphoristic forms.