If we are clear that during the whole of a man’s waking life he is wearing out his physical body and that life in the daytime has fundamentally a destructive effect — as indeed we realise when we get tired — it will be evident that since in the morning we are able to go on consciously with our work, the destruction can be made good during the night.
So, whereas in our waking state we are working all the time destructively on our bodily organism, at night, on the contrary, we are engaged in repairing the damage by replenishing our bodily vigour. We are then carrying out an activity beyond the range of consciousness. Directly we revert to any degree of consciousness, there arise those strange dream pictures that are so closely related to life in the body. We need remember only how bodily ailments may sometimes find expression in these pictures, showing where consciousness is involved.
Since after death the physical body disappears, no effects of exhaustion have to be made good. Hence the forces expended during sleep on the physical body withdraw again into the soul after death, enabling it, free of the physical body, to use them for itself; and between death and a new birth they become the soul’s consciousness. In proportion as the soul is freed from the physical and etheric bodies, with everything belonging to them, so does another consciousness arise, one that is not engaged in work on the physical body and for that reason unable to be aware of itself.
Source: Rudolf Steiner – GA 61 – The Nature of Eternity – Berlin, March 21st, 1912
Franziska Steiner – mother of Rudolf