Have you ever sat in a lighted room at night, reading or talking, and suddenly the lights go out? What's the first thing you say? Usually everyone says, "Who turned out the light?"
In this age of electricity, light is something we take for granted. Few of us ever experience total darkness. In the city, we have street lights which come on automatically as soon as it begins to get dark. In the country, most farms have a mercury vapor light that stays on all night for security reasons. Consequently, most of us never get a good look at the stars as we used to when all the lights went out at night.
If you ever get the chance to go out in the desert at night do it. The darkness on nights with no moon or star light is so total someone could be standing right next to you and you wouldn't know it.
This text from John's gospel is about darkness and light: "And this is the judgment," John says, "that the light has come into the world and people loved darkness rather than light because their deeds were evil."