Even though I disagree with the basic approach of Professor Evan Thompson in the trailer to his new book due out in the Autumn Waking, Dreaming, Being: Self and Consciousness in Neuroscience, Meditation, and Philosophy I found it stimulating dreamless sleep and I thought a summary of the advaitic position as I understand it from the writings of Sankara might be useful.
In the Upanisads the altering of the felt nature of consciousness as it moves through the various modalities of waking, dream, and deep dreamless sleep (sushupti) is central to the understanding of self-nature and self-identity. Deep Dreamless Sleep is what S.T.Coleridge would have called a protophaenomenon.
The naturalist, who cannot or will not see, that one fact isoften worth a thousand , as including them all in itself,and that it first makes all the others facts ; who has notthe head to comprehend, the soul to reverence, a centralexperiment or observation ( what the Greeks would perhaps have called a protophaenomenon ) ; will never receive an auspicious answer from the oracle of nature.From Essay VII on thePrinciples of Method.(The Friend)
That is to say D.S. (the knowledge that we have been in a state of dreamless sleep) is like an experiment of consciousness upon itself revealing its own structure. The core of the insight is simple and yet so profound, and so ordinary that it is overlooked. How do we know that we have slept soundly? In brief, that knowledge cannot be the result of an inference. We might infer as to how long we slept but as to the bare fact it is our experience that we are perfectly aware of it without any external aids. Might we not have been told 'you were asleep' upon waking up in our childhood and associated that experience with 'sleep'. That slow emerging into consciousness &c. In other words it is a learned language game. The assumption here is that D.S. is a state of pure blank nescience that has to be inferred in some way. It is obvious that we do not remember that we slept, for it must be an epistemic bedrock that we can only remember what we experienced. That would also apply to chemical traces left in the brain by the state of sleep which are 'read off' on waking. Those traces would be like the multitude of other somatic processes that we don't need to know about. In any case the trace if given as information is given now and is not 'about' then.
That this has never cropped up as a question in Western Philosophy barring a tangential reference by Thomas Reid in a rebuttal of Locke's theory of Identity and then not in the same sense is an indication of how deep the inner ravine of mental subject/mental objects is. The assumption is that if there is no consciousness in D.S. then how we know we were in it must be from an external source. If not, the knowledge should never have occurred at all. There would simply be sensations of tiredness, a blessed abatement of consciousness and that succeeded by the slow ascension to the waking state. In between there would be nothing.
Sankara and Ramana Maharshi stress this indication of the fact that - "the knowledge of the knower is never lost”.
That it does not know in that state is because, though knowing then, it does not know; for the knower's function of knowing can never be lost, because it is imperishable. But there is not that second thing separate from it which it can know.IV.iii.30 trans. Swami Madhavananda pub.Advaita Ashrama.
In the Commentary Sankara deals with some objections which he goes into in a more detailed way in Upadesasahasri untrammelled by linkage to a text. Remember he is approaching it from the objection to the eternal nature of knowledge and its identity with the self, his philosophic milieu was broadly nondualistic so the fact of the knowledge that we have been in a state of deep dreamless sleep is not in dispute.
#92: Disciple: -"But I have shown an exception, namely, I have(from Upadesa Sahasri tran.Swami Jagadananda pub.Sri Ramakrishna Math)
no consciousness in deep sleep."
#93. Teacher.-" No, you contradict yourself."
Disciple - "How is it a contradiction?"
Teacher.-" You contradict yourself by saying that you are
not conscious when , as a matter of fact, you are so."
Disciple. - "But Sir, I was never conscious of
consciousness or of anything else in deep sleep."
Teacher. - "You are then conscious in deep sleep. For you deny the existence of the objects of knowledge (in that state) but not
that of Knowledge. I have told you that what is your consciousness is nothing but absolute Knowledge. The Consciousness owing to whose presence you deny (the existence of things in deep sleep) by saying, `I was conscious of nothing is the Knowledge, the Consciousness which is your Self. As it never ceases to exist, Its eternal immutability is self-evident and does not depend on any evidence; for an object of Knowledge different from the self-evident Knower depends on an evidence in order to be known. Other than the object the eternal Knowledge that is indispensable in proving non-conscious things different from Itself, is immutable; for It is always of a self-evident nature. Just as iron, water, etc., which are not of the nature of light and heat, depend for them on the sun, fire and other things other than themselves, but the sun and fire, themselves always of the nature of light and heat, do not depend for them on anything else; so being of the nature of pure Knowledge, It does not depend on any evidence to prove that It exists or that It is the Knower."
In short we are conscious in deep sleep for we can say - 'I was conscious of nothing'. To throw this idea aside as a species of trifling sophistry is a temptation given that we are so much under the sway of the contents of consciousness picture of awareness - no contents, no awareness.
The significance of the bare fact as explained through an analogy struck me in the way that analogies often will. We feel their explanatory power more than we understand them in that they baffle the system of thought that we are at the moment using. It works like a wisdom virus unmaking our ignorance.
Tripura Rahasya or The Wisdom beyond the Trinity was where I encountered it. Though famous in Sanskrit; Bhagavan Ramana Maharshi regarded it as one of the greatest works expounding the Advaitic philosophy, it was not available in English, a fact which he regretted. A devotee translated it and the ashram have since taken over the copyright. It is a most peculiar work. Allegory is mixed with legend and deep reflection on the nature of reality and the sorts of samadhi. Scholars distinguish it from Advaita Vedanta and ally it to the system called the Tantric or the Sakta.
However in both systems the favourite example of the world being an image reflected in consciousness as images in a mirror is used.
-"Distinguish between the changeless truth and the changeful untruth and scrutinise the world comprised of these two factors, changeful phenomena and changeless subjective consciousness, like the unchanging light of the mirror and the changing images in it". pg. 86 Tr.Ra.
Further down page 124/5 in Tr.Ra. the mirror analogy is carried on into the state of Deep Sleep. It is given in the form of a dialogue between the sage King Janaka and a Brahmin interlocutor.
-"O King, if it is as you say that the mind made passive by elimination of thoughts is quite pure and capable of manifesting Supreme Consciousness, then sleep will do it by itself, since it satisfies your condition and there is no need for any kind of effort".(Pgs.124/5 Tripura Rahasya. tran. Swami Ramananda Saraswathi.publ.
Thus questioned by the Brahmin youth, the King replied,
-"I will satisfy you on this point. Listen carefully. The mind is truly abstracted in sleep. But then its light is screened by darkness, so how can it manifest its true nature? A mirror covered with tar does not reflect images but can it reflect space either? Is it enough, in that case, that images are eliminated in order to reveal the space reflected in the mirror? In the same manner, the mind is veiled by the darkness of sleep and rendered unfit for illumining thoughts. Would such eclipse of the mind reveal the glimmer of consciousness?.........
Moreover pursue the analogy of the tarred mirror. The tar may prevent the images from being seen, but the quality of the mirror is not affected, for the outer coating of tar must be reflected in the interior of the mirror. So also the mind, though diverted from dreams and wakefulness, is still in the grip of dark sleep and not free from qualities. This is evident by the recollection of the dark ignorance of sleep when one wakes".
The image of the tarred mirror was the crystallising one. The quiescence of the physical brings a natural darkness to the awareness of the individual but the nature of the pervading consciousness does not change.
I still hold to the view that 'recollection' is not correct for the immediate knowledge that we have on waking that we were asleep. It is that peculiar sort of knowledge that we cannot not know. It might be said that what we cannot not know we cannot know either. There is no coming or going in that awareness it always is.