The Self is the one Reality that always exists, and it is by the light of the Self that all other things are seen. We forget it and concentrate on the appearance. The light in the hall burns both when persons are present and when they are absent, both when persons are enacting something, as in a theatre, and when nothing is being enacted.
It is the light which enables us to see the hall, the persons and the acting. We are so engrossed with the objects or appearances revealed by the light, that we pay no attention to the light.
In the waking or dream state in which things appear, and in the sleep state in which we see nothing, there is always the light of Consciousness or Self, like the hall lamp which is always burning.
The thing to do is to concentrate on the seer and not on the seen, not on the objects, but on the Light which reveals them.