Mike Austin: Can you describe what type of mental phenomena dreaming is?
Dalai Latma: There are techniques for causing dreams to become non-mistaken as to the ultimate nature of reality. Otherwise, dreams, though there are unusual ones, are of little value in developing the mind.
Mike Austin: Is it just because the mind is so restless that even when the body sleeps, it continues to function?
Dalai Latma: When one is sleeping without dreams - in a dreamless state there is less conceptuality. When dreams appear, one generates desire, hatred and so forth; and then of course, there is a lot of conceptuality. A dream consciousness is easier to change or transform. The experience of pleasure and pain in it can influence the same experience by a coarser consciousness when awake. Because a dream consciousness is more subtle than a waking consciousness, it is more effective.
But now, a special dream body is a case of the coarse body actually being left. There are cases of this due to one’s former actions or karma, like a gift at birth, a talent. These people can experience what is actually going on at this time externally - beyond their bodies.
There are also cases of people who train in making use of the special dream body. Not to lose time in their religious practice, they often spread the pages of a book out before going to sleep. During sleep they then depart from their bodies and spend that time reading. The pages would be separated before because the dream body is incapable of moving coarse physical matter.