What is the absence of light and darkness?

Life is an illuminated substance. 

It is a substance that gives off light. And the more highly developed a life is, the greater is the amount of light that the life gives off, and the more brilliant is this light until this light reaches a brilliancy that is unendurable to physical vision and, therefore, blinding to those of us who are of this earth plane.

A spirit in all the early stages of its development  is a mere speck of light, round or somewhat oval in shape and no larger than a pinpoint—usually not so large. 

And this is true even of at least some of the life that has attained to a considerable distance on its road to completion.

Fragments of Spiritual Knowledge Pertaining to the Spiritual World