What is consciousness: physical or non-physical?

The following is an excerpt from a samvaad (dialogue) session with Acharya Prashant.

Questioner : Acharya Ji, whenever you have been asked what is consciousness, you have simply said that, “All that is mind, mind-stuff is consciousness.” The question that’s not relevant personally to me but still l thought like– ‘Material stuff is visible, it can be touched, so that is one thing. The other thing is the Atman which is beyond knowledge. This consciousness thing is somewhere in between.’ So I mean, many people have asked this foolish question, “Where does consciousness resides and everything.” I’m not trying to ask that but still – ‘What is it? What constitutes it? How does it work?’

Acharya Prashant: How does this material body come to be conscious is a great mystery. There is no answer to that. You cannot similarly answer to the question, “How does this material body come to become unconscious? Or how does Prana leave the body?”

Ramana Maharshi used to explain this by saying that, “There is a ‘Jada-Chetan Granthi’ somewhere in the body, where the ‘Jadata’ which is the ‘material body’ meets ‘consciousness–pure consciousness.’ And he used to say that, “That Granthi, that knot is the cause of all human suffering. So you have to severe this knot, you have to cut that knot somewhere.”