What is that thing through which we see everything? Light.
What is that thing which in principle can never be seen? Light.
What is light? Light is the dark revealer; itself veiled, it unveils everything else.
And the light of this world is only the shadow of that Intelligible Light which shines in your dreamless sleep, the home to which you return every night after a day of surfing on the ocean of life. Though you can never describe the dreamless state you know for a fact that it is a state of your reality. You don’t know what it is but you know that it is. Like dreamless sleep, Truth too is beyond whatness: It is but It is free of being anything in particular.
Whoever claims that there is no consciousness in dreamless sleep is claiming two things that contradict one another: First, by saying so he/she admits that there is such a thing as dreamless state, as opposed to a dreaming or a waking state. But then he denies in it the very existence of a consciousness that must be there in order for him to know about such a dreamless state. Exactly how did you “know” that there isn’t consciousness in that state? You must have been there yourself in one form or another! And if you hadn’t, you wouldn’t even know about it, let alone talk about it.
In dreamless sleep there is certainly no cognition going on but consciousness is there ever present as it is in all other states of consciousness. So this state should be characterized with the absence of cognition rather than the absence of consciousness, the latter leading to contradiction.
If there is no experience in dreamless sleep it is because there is no cognition to be illumined by the ever shining light of consciousness. Cognition is entirely conditioned and determined by the psycho-physical constitution of the individual being while consciousness is universal and transcendent to the plane of nature cognition.
Experience arises when the Intelligible Light, i.e. consciousness, is reflected back to Itself off of a non-consciousness, matter or cognition. In the absence of a non-consciousness, of a duality, there is nothing to reflect the light of consciousness so that no experience arises; however, the light is still there.
Same is true of the light of this world: That the outer space is dark, as opposed to our sky, is because there is no air or matter to reflect the light. In fact, the empty space is filled with visible light. We cannot see it because light, Intelligible or worldly, is the dark revealer: It only manifests the face of the Other and not Its own.