15. Ajatasatru said: "It is  contrary to usual practice that a brahmin should approach a kshatriya,  thinking: 'He will teach me about Brahman.' Nevertheless, I will instruct  you." So saying, he took Gargya by the hand and rose. They came to a  sleeping man. Ajatasatru called that sleeping man by using various words such  as O Great One, O White-robed One, O Radiant One, O Soma etc., which were used  by Balaki earlier when he was referring to Brahman. But that sleeping man did  not get up. The king pushed him again and again with his hand till he awoke.  Then he got up. This incident became an occasion for further instruction by  Ajatasatru on the nature of the Self. 
This is how  philosophy begins here with a new turn. This philosophy is the study of three  states – waking, dream and deep sleep – jagrat, svapna and susupti  avastha which is technically called “avasthatraya prakriya”,  methodology of three states to understand about the truth of the world and  human beings.  
16. Ajatasatru said to Gargya: "Do  you know this person was sleeping and would not get up when I called him by the  names of the Prana which is the reality, as you have mentioned to me?  But when I shook him, he woke up. Now, this intellectual self, who is the human  being, was not conscious of anything when it was asleep. Where was it when it  was sleeping? Where did this person go? There is an entity in the human  individual, called intellectual being, Vijnana maya-Purusha. This is the  highest endowment that you can think of in the human individual. As a matter of  fact, there is nothing in the human being except the intellect. This is the  highest property that one can have. Where has it gone during deep sleep? Where  was it buried, and where from has it come now when the body was being shaken by  me? What is the answer to this question?  Balaki, can you tell me where this was when  asleep?" 
Atman reflected  in the buddhi (intellect) or Atman limited by the upadhi of buddhi appears as the Jiva or individual soul. The question implies that the Jiva does  not experience the notions of action, agency and result during deep sleep. At  that time Atman remains in a transcendental state. When the Jiva awakes it  deviates from its true nature and becomes conscious of action, agency and  result.
Gargya had no  answer and replied “I do not know where it has gone or from where it has come.
The question  raised by Ajatasatru was answered by himself as Balaki did not know the answer.  The aim is to show that there is in Atman or Pure Consciousness, a total  absence of action, agency and experience of the result.
17. Ajatasatru continues his  instruction. It is difficult to understand what the true human being or the  true Self is. The true Self is not anything that is visible, not even something  intelligible, easily. The external form of the individual, which has an  apparent consciousness, intelligence and a capacity to act, is not the true  Self of the individual, because all these appurtenances of action, and the  so-called individuality of ours, cease to be self-conscious in sleep. The  energy is withdrawn; consciousness is withdrawn; the ability to perceive is  withdrawn. It appears as if life itself has gone. There is a practical  non-existence of the individual for all conceivable purposes. What happens is  that the central consciousness, which is the Self, draws forth into itself all  the energies of the external vestures, viz. the body, the Prana, the  senses, the mind, etc., and rests in itself without having the need to  communicate with anything else outside. It is only in the state of deep sleep  that the self goes back to its own pristine purity. 
It suggests why  Ajatasatru felt the need to go to a sleeping man, rather than to a waking  individual for the purpose of citing an example in instruction. The reason is that  in the waking state the self is entangled in object-consciousness whereas in  sleep it is withdrawn into itself. The analysis of the individual in the waking  condition is difficult. We are split into a thousand fragments in the waking  condition. We are not an integrated personality in waking. We are distracted  individuals and have no peace of mind when we are awake. We run here and there  in the waking state for the reason that we are already split into fragments. We  are cut into parts. We are never whole in the waking state. And, so, it is  difficult in the waking condition to analyze the true nature of the self. 
The waking one  may appear as good as the sleeping one. But, what is the difference? Both are  individuals, both are human beings; in both the self exists, no doubt. But the  difference is that consciousness is not centered in itself in the waking state.  It is, then, scattered outside among objects. It is meandering through all  sundry things, and, therefore, the teaching in the waking condition is more  difficult than in the context of sleep. What happens in sleep? Ajatasatru says  that the self is withdrawn in sleep. It is in the centre of itself. It is in  the cosmic space, the ether of consciousness. 
When everything  is withdrawn by the self into itself, that state is called Svapa, in  Sanskrit - tad  grhita eva prano bhavati, grhita vak, grhitam caksuh, grhitam srotram, grhitam  mana.: what happens in sleep? The Pranas are drawn back to the self.  They gravitate towards the self, rather than to objects of sense. Speech also  is withdrawn; you cannot express anything in language, during sleep. The eyes  are withdrawn; you cannot see anything there. The ears are withdrawn; you  cannot hear anything. The mind, too, is withdrawn, you cannot think, also. All  transaction with external things is put an end to and one remains what one  really is in the state of deep sleep. When the organs are absorbed or  restrained in deep sleep, the self rests in its true nature.
18. Now the dream state. We have our  own world in dream. We manufacture our own country, our own residence, our own  activity and everything else. This creation of a new world in dream is out of  the material of past experience in previous waking conditions. These are the  worlds which the dreamer creates. You become an emperor, or a learned man,  whatever you like, in dream, according to your own wish. You become high and  you can become low; you are rich and you are poor; you are happy or unhappy;  you are this and that. Like a lord do you wander in the world of dream. As an  emperor or a king may go for excursions in his own country, with a large  retinue, hither and thither, likewise is this intellectual or psychological  self moving in the world of dream with all the objects that it has created out  of its own desires; and it appears as if it is in a world of freedom which has  been created by its own imagination and will. 
From the  standpoint of Reality there is no difference between dream and waking  experience. The world experienced in the waking state is as unreal as the dream  world. Since the gross and subtle worlds in these two states are perceived by  the seer, the self, it goes without saying that self, the perceiver, is  different from the perceived and therefore it is always pure. – Sankaracharya.
19. What happens when the dream ceases  and there is a withdrawal of consciousness into sleep? One knows nothing. There  are various nerve currents within. They are called the Hita-Nadis. They  are supposed to be seventy-two thousand in number - dva-saptatih sahasrani.  They ramify themselves in every direction throughout the body, and it is through  these nerve currents that the mind travels in the waking and the dreaming  states drawing the consciousness of the self together with it, and so it  appears that we are conscious physically. They are all centered, as if in the  hub of a wheel, in the centre of the heart, which is called the Puritat where the mind sleeps when it is free from all activity. The Puritat is  also a central nerve current where the mind gets lodged in the state of deep  sleep. It withdraws itself from all these seventy-two thousand nerve channels,  when it is about to sleep.  
Our physical  consciousness, or bodily consciousness, the feeling that the body is conscious  in the waking state, is brought about by a mixture of properties affected by  the activity of the mind which is the medium between the physical body and the  self inside. The mind is not conscious by itself. It is something like a mirror  which is not self-luminous. A mirror is not light, for the light comes from  somewhere else. But, though the mirror has no light of its own, it can shine  through borrowed light to such an extent that we may see only the light there  and not the mirror. 
Likewise, the  mind is a kind of transparent substance, we may say, through which the light of  the self passes. And it completely absorbs the consciousness into itself. It  becomes apparently self-conscious. As the light of the sun may get absorbed  into the object, e.g., the glass pane, and the glass itself may appear shining,  as if it is itself the light, so the mind, the psychological being in us,  apparently assumes the role of consciousness for practical activity in daily  life, and it charges the nerve currents with consciousness when it moves  through them.
When it absorbs  itself into the centre and goes to the Puritat, it does not move outwardly  through the nerve currents and hence the body loses consciousness. The body had  no consciousness even before, and its real nature is exposed now in sleep. It  appeared to be conscious on account of the vibration of consciousness which was  communicated to it through the mind. The mind having been withdrawn in sleep,  consciousness also, automatically, withdraws itself, because the consciousness  we have is nothing but mental consciousness. And when the mind is thus  withdrawn, everything that is sustained by the mind also is put to sleep. 
You cannot know  that you are breathing; eyes cannot see; and so on.  They are able to discharge their functions because  they are charged with consciousness. As if a magnet is brought before an iron  rod which gets charged by the magnet on account of its proximity to it, the  sense-organs get charged with consciousness through their proximity to the  mind, and, so, they begin to act as if they are alive by themselves. But when  this withdrawal of the mind takes place in sleep when it goes back to get  itself lodged in the Puritat, the senses lose contact with  consciousness. Then the eyes cannot see; the ears cannot hear, etc.