In the fifth verse, Śankarācārya enumerated various systems of philosophy, in which there are varieties of confusion regarding the real nature of “I”; and in this sixth verse, Śankarācārya wants to refute the main system, known as mādhyamika bauddisam; or śūnyavādaḥ; which is one of the main pūrvapakṣis of vedāntaḥ. And Śankarācārya does not refute the other systems, because this shoonya vadi has already refuted others and therefore he becomes the main challenger; and therefore Śankarācārya refutes the śūnyavādaḥ in the 6th verse.
The śūnyavādi points out that the essential nature of me; or the I, is nothingness or emptiness. Not only the individual, even the essential nature of the world is nothingness or emptiness. And in support of this conclusion, he takes our sleep experience as the pramāṇam or truth. In sleep we do not experience anything; there is no objective world. In sleep we do not experience the subject also; so neither ‘seen’ is there; nor is there the ‘seer’; neither the ‘heard’ nor the ‘hearer’. Therefore the subject as well as the object, both of them are not there; and therefore śūnyam is the tatvam is their conclusion.
Now Śankarācārya shows in this verse; that in deep sleep state, it is not śūnyam or emptiness. In deep sleep state, there is pure existence; but it is an unqualified existence; which is not available for any transaction. Only qualified existence is available for transaction; unqualified existence is not available for transaction. And therefore we make a mistake that it is emptiness; because we have a general misconception, whatever is not available for transaction is non-existent. This is one of the intellectual confusions. We think the space is nothingness; because space is not available for transaction. But the truth is that, space is not emptiness or nothingness, it is a positive entity. But generally we mistake space as emptiness, because it is not avialable for seeing, touching or any other local view. The same mistake is extended to the pure existence also; because it is not available for vyavahara. And therefore, in sleep, non-transactional existence is available which is my nature. This is the essence of this verse.
To highlight the mistake or the illusion that Sunyavadis have about “existence or otherwise” Adi Sankara brings out an incident that happened during the “Samudra Manthan” (churning of the ocean) as told in the Puranas.
The story of Rahu & Ketu and Maya
According to Puranas, the birth of Rahu and Ketu dates back to the earliest of times.‘Samudra Manthan’ is regarded as one of the most important events in the history of Hindu civilization. The Solar and Lunar eclipse is also associated with ‘Samudra Manthan’. When the ocean was churned by the Asuras and Devas, ‘Amrit’ was produced. This Amrit was stolen by Asuras and to obtain the Amrit, Lord Vishnu took incarnation in the form of a beautiful damsel ‘Mohini’ and tried to please and distract the demons. On receiving the Amrit, Mohini came to Devas to distribute it to them. ‘Svarbhanu’, one of the asuras changed his appearance to a deva to obtain some portion of the Amrit. However, Surya (Sun) and the Chandra (Moon) realized that Svarbhanu was an Asura and not one of the devas. Knowing this, Lord Vishnu severed Svarbhanu’s head with his discus, the Sudarshan Charka. However, even though his head and body became separated, they still remained immortal as the separate entity because before his head was served, he managed to drink a drop of the nectar from the Amrit. The Head is known as Rahu and the headless body is the Ketu. Since then Rahu and Ketu constantly chase the Sun and the Moon for revenge as they are the cause of separating the head and body of the Asura Rahu. It is a popular belief that when they succeed in catching Sun and Moon they swallow them causing Solar or Lunar eclipse but they can’t hold them for long and Sun and Moon emerge again intact as they also had nectar and are immortal.