2. Consciousness in Sleeping and Waking States

In the preceding lectures, I have been calling attention to the fact that there will still be a great deal to say about a certain problem or question, even though it has already been the subject of discussion here from a great variety of viewpoints. That is the question of the alternating states of waking and sleeping in human beings. I have repeatedly spoken in public lectures of how this problem of sleep has occupied a more materialistically oriented science also, and how it is being handled. On several occasions I have referred to some of the various attempts that have been made to solve it. There is the so-called exhaustion theory, which is only one of the many that have been advanced in recent decades. This theory holds that we secrete substances resulting from the wear and tear of work and of our other activities during waking life, and that the sleeping state somehow eliminates these exhaustion products, which are then formed anew in the following period of waking consciousness.