As ultimate truth or Brahman is beyond the physical experience, so is it beyond physical based knowledge.

Waves have temporary existence, but the sea is permanent. In the same way, the three states are passing and consciousness, the infinite and the endless is the substratum upon which the mind or universe appears.

Because of one’s inability to grasp the true nature of consciousness, only with the help of deeper inquiry, analysis and reasoning, whatever positive descriptions one develops about consciousness in the light of the discrimination will remain in the level of physical experience.   

As ultimate truth or Brahman is beyond the physical experience, so is it beyond physical based knowledge.

 At the same time the word `existence' cannot be attributed to consciousness and to the empirical world in the same way, for consciousness’s existence is of a different nature. The existence of consciousness is opposed to all empirical existence, so that in comparison with this it can just as well be considered as non-existence.

 Consciousness is the formless substance and witness of all the three states.  The nature of consciousness is so transcendent that it cannot be compared with anything in the world one knows. At the same time, consciousness is present in all its manifestations, for without the consciousness nothing can exist. Yet the empirical experience of consciousness is not possible. Thus, consciousness is that unalterable and absolute Being, which remains identical with itself in all its manifestations. 

It is the basis and ground of all experience, and is different from the space-time-cause world. Consciousness has nothing similar to it, nothing different from it, and no internal differentiation, for all these are objective distinctions. It is non-, non-objective and wholly other, but it is not non-being.