A stone does not remember anything. The memory of a past experience, here, in this case, memory of sleep, should imply the presence of some sort of a consciousness. If the consciousness was completely obliterated in sleep. One would be like a stone, and a stone says nothing. There is a strange mystery within us.
Man is a miracle.
He is not an ordinary individual as he thinks he is. Man is not a Tom, Dick, or Harry, as he appears. Every human being is a wonder in himself, or herself, and it is the study of deep sleep that unravels the mysteries of man. In other conditions, man knows very little about himself. Most of the philosophers of the West confine themselves to the waking experience.