In much of his fiction, Arthur C. Clarke supports the idea that knowledge, particularly knowledge of technology, equals power—and not just physical power, but psychological power as well. One of Clarke's three "Laws" is the idea that "any sufficiently advanced technology is indistinguishable from magic." In Childhood's End, the Overlords use their technology to achieve both these ends. The vast technological superiority of the Overlords apparently knows no bounds. They can spy on anything that happens on the surface; they can project artificial copies of their ships so convincing that they even make a sound as they enter the atmosphere; they can inflict pain without causing a wound; they can block out the sun over specific geographic areas; and they can alter a planet's gravity, to list just a few of their powers. They also have the Stardrive, which lets them fly their ships at the speed of light.
On Earth, the Overlords use this technological power to exert benevolent but totalitarian rule. They create a utopia on Earth through what Karellen calls a "correct use of power." "Correct" in his idea means "efficient"; rather than destroying a rebellious country, Karellen destroys its power by driving its leaders mad, or with a simple—but harmless—show of power, such as blotting out the sun. But Karellen's use of the term "correct" does not include a value judgment on whether the action being taken is the "right" one. Stormgren's objection to this claim is that it sounds like "might makes right," to which Karellen replies with his argument about efficient and inefficient uses of power. Karellen does not address Stormgren's true objection: that regardless of how efficient the Overlords' use of their "might" is, they are still determining what is "right." As the existence of groups such as the Freedom League reveals, not everyone on Earth believes that the Overlords' efforts to create a utopia are what is right for humanity.
Of course, another aspect of this theme is the limitations of technology. In Childhood's End, knowledge and technology is a dead-end. The Overlords have mastered technology, but they are unable to make the transcendental leap to the next stage, that of the Overmind. This idea is unique among most of Clarke's works, which generally espouse the idea that knowledge and technology represents the future of mankind. In order for it to surpass technology, Clarke is forced to make the Overmind a vague, mystical, and perhaps even mythological entity.
While the main concepts of Childhood's End revolve around the irony of the Overlords as benevolent masters that look like "devils" and the division between technological and evolutionary achievement, the book also deals heavily with the possible problems of a utopian society. Before we are even aware that the Overlords have started making beneficial changes to the Earth's economic and political systems, we are introduced to the Freedom League, composed of humans who object to the Overlords' meddling in human affairs. The Freedom League does not object to the policies of the Overlords, it objects to the Overlords' very presence. To a degree, Wainwright is correct; the Overlords remove all of humanity's dreams, goals, aspirations, and struggles. In eliminating conflict, the Overlords put humans in a position where they have only once choice: begin educating themselves and exploring, or decline into stagnation. Since the Overlords refuse to allow mankind to enter space, there is no choice but stagnation. For a time, people attempt to fight off boredom through education and entertainment. Eventually, and perhaps inevitably, people like Jan Rodricks became restless. As the narrator notes, "no utopia can ever give satisfaction to everyone." As a utopia progresses, the more dissatisfied or degraded its people will become. Boredom will give way to violence and moral depravity. This often happens whenever things are going well for a large number of people and often represents the self-destructive downfall of many a government.
Moral depravity is not the only problem that utopias eventually face. There is also the problem of artistic stagnation, which is addressed in the novel by the creation of New Athens. Without discontentment, without strife or struggle, artistry will necessarily suffer. As more people have more leisure time, there is more art, and thus humanity begins to drown in so much art that there is no clear way of determining "good" from "bad." The New Athens colony was doomed from the start; it was merely an attempt to create a utopia within a utopia.
But aside from addressing the practical—and perhaps rather obvious—problems of utopian society, Childhood's End also presents a rather problematic situation. Evolution works primarily by isolating those more fit to survive; the weak die, leaving the strong and the adaptable. But as the standard of living is raised across the globe, as even the lazy are allowed to live out their lives with the basic necessities, there is none of this weeding out process going on. Therefore, when the children begin their strange transformation into the Overmind, the process cannot be considered "evolution." In order for it to be considered so, one must alter the definition of "adversity": in the face of utopian stagnation, the children must mutate into the Overmind in order to fight off their complete degradation into animals.