18 Dream and Sleep
sutra 1.58 or on the knowledge of dream and of (dreamless) sleep
One commentator understands the first part of this sutra as meaning that when a man awakens from a dream of a god, he should remain as long as possible in the memory of that dream; the dreamless sleep he understands as the sleep of a man in whom the doshas are very attenuated. These meditations, made on awakening, are thought to give knowledge.
Shankara, however, though he does not necessarily deny such an interpretation, takes it to mean meditating on the subtle analysis of dream and sleep. ‘Knowledge of dream’ does not mean knowledge of any object in a dream; the mind meditates on its own essence, by means of consideration of dream. The yogiis to meditate on knowledge as it is in itself, apart from any objects. Knowledge in itself is illumination, and he is to meditate on the true nature of knowledge, but not on remembered dream objects, because that would involve being implicated in them.
Deep sleep consists of non-perception of any individual thing, and the meditation is on the idea of non-existence, namely peaceful, infinite, experienced, and unmoving. It is natural, concludes Shankara, that steadiness of the mind should come about by these meditations on dream and sleep.
To perform them requires a good deal of careful analysis first. The points are elaborately discussed in some of Shankara’s other commentaries, but here he just refers to them, and the arguments can only be outlined. In dream, there is a light. What is the light under which the objects of the dream are seen? It may be said that it is the memory of the sun and so on, but a memory is not a light. What is the light which brings the memory-impressions to clear manifestation as dream-objects? To do this meditation the yogisits in a stable posture, closes his eyes, and allows the mind to make pictures. Then he tries to isolate the light under which the pictures are known.
In the case of dreamless sleep, a crucial point in Shankara’s philosophy is that consciousness is not dissolved along with the sense-impressions and thoughts. In ordinary experience it is not distinguished from them.
It is accepted by the yogis that in dreamless sleep there is no perception of any individual thing, and Shankara says that fact must have been ‘experienced’. The absence of sense-perceptions, and of dream-objects, is known. On waking a man says, ‘I did not dream.’ (It is true that his memory may be at fault, but this applied to testimony about waking also, and does not invalidate the fact that he can make true statements about the past.) He may also say, ‘I was happy.’ The Indian psychology investigates this statement in great detail. It is not merely that the one going to sleep looks forward to cessation of anxiety; a man who has no anxiety still shows by his behaviour that he looks forward to sleep. In this commentary Shankara adds one more indication, namely that somehow a man asleep is aware of the passing of time. He instances a man in an inner room, shielded from all possible outside clues (like songs of birds, changes of light and so on), who nevertheless knows immediately on waking, ‘I have slept a long time’ or ‘I have slept a short time’.
Another commentator cites the cases of men who meditate before sleeping that they want to get up at a particular time, and who do awake at that time. That there are some people who can reliably do this, waking at particular times arbitrarily chosen by others, has been confirmed under laboratory conditions.
A central point is that many people suppose that the state-ments ‘I knew nothing’ and ‘I did not know’ are the same. However, parallel statements about sense-perception show that there is a difference. A blind man in a dark room does not see; a normal man with his eyes open sees nothing – he can make a statement ‘there was nothing visible there’. The blind man cannot make this statement.
Some snakes have organs sensitive to small changes in temperature; they can focus these to detect the location of even a very weak source of heat, for instance a mouse. If this snake is in a dark empty room, it ‘heat-senses’ nothing, and knows there is no mouse there; a man in that room does not.heat-sense, and does not know whether there is a mouse there or not.
To do this meditation the yogi consciously enters into deep sleep. Goethe was evidently aware of one form of it; he wrote in a letter to Humboldt that he had discovered a method of ‘entering unconsciousness consciously’, and he remarked that it is a secret of inspiration. There are many cases of scientists and artists who found inspiration in their minds on waking from sleep – Helmholtz and Hugo Wolf are examples. Shankara, commenting on a phrase of an Upanishad, says that in deep sleep the individual self is connected with the cosmic energy and is therefore potentially omniscient.