The viewing screen in the conference room in which Stormgren and Karellen periodically meet functions as a minor symbol of the Overlords’ rule: it is opaque and deceptive, based on illusion and the inclination of humanity to not question its own assumptions.
Stormgren simply assumes that the viewing screen is in fact a display of some sort. He has never questioned that assumption in the five years that he has been meeting with Karellen, until he finally comes to discover that it is simply a sheet of one-way glass through which Karellen watches him. Despite the Overlords’ vast technological capacity, the illusion is simple, merely a trick of the light. This is representative of the Overlords’ use of their power to rule in general—like the trick with the viewing screen, much of the Overlords’ perceived power is similarly an illusion. For example, the threatening Overlord ships that hover over humanity for fifty years are really just mirages.
Despite Stormgren’s friendship with Karellen and despite the Overlords’ displayed affection for humanity, the Overlords keep their plans as opaque as the viewing screen, never being fully honest about their own nature, their intentions, or what is transpiring around them. The Overlords base their entire rule on such deceptions, which are often comparatively simple, and their refusal to be honest or open with their subjects only reinforces their role as authoritarians, regardless of how friendly or benevolent they may appear to be.
Karellen’s One-Way Screen Quotes in Childhood’s End
“All of our sojourn here has been based on a vast deception, a concealment of truths which you were not ready to face.”