It contains two opposing sides engaged in an unequivocal struggle between Good and Evil. The Good side is aligned with benevolent celestial spirits and its culture and morality is traditional (more or less...). The Evil side is aligned with malignant terrestrial spirits and its culture and morality is a parade of horrors intertwined with amoral science and unhinged progressiveness. By the way, neither side is committed to a convincing ethic of human equality or democracy; it seems both Good and Evil demand their underlings to know and follow their preassigned roles. I should point out that the start is slow and semi-realistic, yet the characters and the events are increasingly bizarre as the plot proceeds. The outrageous climax is a quite literal deus ex machina. In one scene, a character writes propaganda articles for newspapers. In another scene, the omniscient narrator peeks briefly into the perspective of a bear.
The Evil side takes the form of an impersonal juggernaut of unrestrained power called the National Institute of Coordinated Experiments. At its deepest level, it's steered by two remarkable antagonists whose surnames are Wither and Frost. Naturally, they're two of the most memorable characters. These portraits of villainy are prime starting-points for dissecting some of the favorite themes of Lewis. As much as possible, I'll try to digest his mere (ha!) theology into standalone nuggets of insight.
Wither is the Deputy Director, the top day-to-day authority of the organization (and one of his unwritten duties is to neutralize the clueless official chief!). However, he wields his power in an unexpected manner: his leadership and communication style is astonishingly vague. He's not openly tyrannical in the slightest. He explicitly instructs his inferiors to act with "elasticity", i.e. serve how they can without conforming to limited job descriptions. He's easily irritated if anyone coerces him to act or speak bluntly. He meanders with his voice, extending his conversations with excessive courtliness until the other participant is worn-down. He also meanders on foot, walking around the organization grounds with no warning of his approach and no planned destination. He's usually friendly and polite to someone's face. Nevertheless, he expects all of his euphemistic "requests" to be obeyed without hesitation in order to prevent him from demonstrating his "hurt" at being ignored.
Wither is an example of someone whose public face is so well-developed that his personality is virtually split into pieces. His habitual mimicry of courtesy is so complete that he feels no need to direct his entire attention to his job. His mask is himself. The disconnected part of him that runs the machine-like organization is itself machine-like. Therefore Wither exhibits two related problems of human nature that Lewis highlighted multiple times.
1) Wither's interactions with others are insincere. For Lewis, insincerity wasn't a harmless social game. It was an insidious path of temptation to the greater problem of self-delusion. Through self-delusion, humans avoid acknowledging their actual motives and thereby also avoid acknowledging their camouflaged innermost "evils". They convince themselves that they're virtuous when even their virtue is underpinned by their beloved flaws. Furthermore, insincerity in society leads to shallow relationships built on passive-aggressive pretenses. Lewis recognized that pride and hatred have as many subtle expressions as love. Regardless of whether someone is religious, these are valuable observations and warnings about human deceptiveness. Sincerity and honesty in communities, including the "community" within a single brain, are values that are tied to the earnest pursuit of truth—a universal humanistic value.
2) On the other hand, perhaps Wither's outward insincerity is a surprisingly accurate reflection of a worse root problem, namely self-disintegration. Perhaps Wither no longer maintains a coherent and unified self-concept, so his thoughts and actions are a mass of contradictions. In that case his blathering managerial persona isn't lying when it gives the false impression that Wither is compassionate; while it's active that persona is being truthful about its own sentiments. Lewis identified disorder as a major characteristic of the natural human state. He emphasized the inborn tendency to drift away from an established idea. Without sustained training and effort, humans lose control over their spontaneous competing impulses. They're prodded to rebel against their ideals, no matter what those ideals happen to be. According to Lewis, the long-term inability or unwillingness to assert self-control eventually produces a pitiful result, when the original tendency toward disorder culminates in full-blown self-disintegration. At that point of no return, the human has ceased to be a unified decision-maker in any meaningful sense. There isn't a brain "executive" that issues overriding directives, or if there is then the executive doesn't retain power of command.
Lewis' intent behind this theme was to claim, "If you refuse to accept the rule of Christianity then you cannot rule yourself successfully." Apart from this abominable non sequitur, his cautionary notion of self-disintegration is valid enough. The human brain is packed full of multitudes of parallel energy-expending neural networks that show subconscious activity. And habits have physical form in these networks. So it's not far-fetched to notice that the subjective experience of consciousness is torn by inner conflicts which demand considerable mediation—"cognitive dissonance" is the preferred label for it. Moreover, it's also not far-fetched to notice that frequency of activation affects the talkativeness of particular networks. Humans who don't "exercise" advanced brain functions, such as imagining future repercussions, certainly can't expect those functions to "win out" during decisions. Self-disintegration is a creeping danger to anyone who wants to live in consistent accordance with their chosen ideals, independent of how they choose to derive their ideals. Pragmatically speaking, cheap ideals without the verification of steady commitment barely deserve to be called "real".
Frost is more secretive. He mostly works in private, but he gains greater and greater prominence as the story unveils the sinister mainspring of the Institute. He's disciplined, direct, abrupt, and severe. Whereas Wither appears to be welcoming and harmless, Frost appears to be cold and menacing. When the two of them converse, he complains about Wither's roundabout speaking, emotional word-choice, and reliance on patient strategies. He's keen on stoic allegiance as opposed to camaraderie. Wither's face sometimes looks lifeless, while Frost's stony face (his eyes concealed by the light falling on his pince-nez glasses) sometimes looks empty of every shred of humanity. And his smile makes the effect worse.
Frost personifies an attempt by Lewis to create a reductio ad absurdum of one of his perennial grievances, "Subjectivism". Subjectivism, as described by Lewis, is the general belief that the qualities or values of objects arise from the observers but not the objects. That is, objects don't embody qualities. For example, when a diligent florist says, "My flower is beautiful," Lewis asserts that Subjectivism interprets the statement as a pure fact about the florist and nothing substantial about the flower. He argues for the opposite idea of object qualities which definitely exist, whether or not human judges agree. His frank concern is that if humans begins to think that these qualities are solely subjective, then they'll doubt the "real" existence of those qualities...with the dreaded final outcome of humans such as Frost who devalue those qualities altogether.
Subjectivism is Frost's philosophy and lifestyle, but it's implied that Frost was taught by a diabolical source. He in turn wishes to initiate others. Thus he gives several lectures on his beliefs. He insists that all emotions are "nothing more" than chemical/biological phenomena, so he encourages intentional rejection of the entire set of illusions. He preaches that feelings and the associated moral judgments are unnecessary impairments to clearheaded analysis and swift action. His ends always justify his means. In effect he's a Sociopath With A Cause, or an ideal pawn for his "dark masters". Part of his unforgettable training method is to systematically provoke revulsion in order to guide his initiates to ignore their instinctual biases.
Nowadays the entire topic puzzles me a little. Dramatizations aside, I don't feel threatened by Subjectivism. My response to it is analogous to my response to the charge of relativism. Subjectivism is a simpleminded caricature. Yes, I'm a heretic who believes that humane ideals are constructed by humans. At the same time, I reject the hasty conclusion that human-constructed ideals are defined without exception by the petty competitive interests of individuals or tribes (or voting blocs?). Given the human capability to develop and apply other sophisticated ideas, ideals could and do achieve the same sophistication. Ideals aren't constrained by originating and then existing within subjects.
But an objector may sputter, "You're missing the main point. Isn't this a blueprint for disaster? If things aren't inherently good or bad or pretty or ugly or prudent or foolish, then subjects could disagree!"
The pragmatist replies, "Yup." It's a pragmatic truth that subjects disagree often about countless objects. Perhaps they agree about the attractiveness of the proud florist's flower. Perhaps not. In either case, the subjectivity of the flower's attractiveness is inconsequential. Just as human subjects construct thoughts about objects, they select which subjective differences matter to them. (I suspect their reactions to the flower matter more to the florist.)
In more important cases like some behavioral ideals, humans feel that every subject should agree. They can accomplish that goal through the many methods that suffice for any sophisticated ideas. To start, they could explain, persuade, and debate. In cases of still-greater importance like bans of despicable acts, humans feel that every subject must agree. Hence they resort to enforcement and various deterrents.
Fortunately, a second pragmatic truth about real-world subjectivity intervenes. Since all humans are linked by common descent and the members of each cultural group are linked by common training during immaturity, most subjects agree about an interrelated collection of vital basics. Human subjectivity has a shared frame of reference, especially in the context of a homogeneous culture. This second truth is a clue for why the objectors to Subjectivism too readily assume that all of the subjective occurrences in their brains are "really" attributes of the objects. They're heavily adapted to their own frame of reference. (If they ever bother to refer to it they may use the unhelpful term "common sense".) Their ingrained subjectivity isn't distinguished from genuine objectivity.
I concede that, to his credit, Lewis sometimes alludes to the significant disparities among individuals and distinct cultures, although he repeatedly emphasizes every similarity he can find. Unlike me, he doesn't interpret these similarities as supporting evidence for a species-wide, deep-rooted evolutionary explanation. Indeed he jumps to the opposite explanation of a singular divine Moral Law imposed on every human soul; he opines that the discrepancies spring out of a universal urge to discard or replace portions of the Law.
Presumably, the threat of those possible rewrites of ideals are why Lewis thought that Subjectivism should be frightening. To the contrary, I now see that the refinement of ideals is a strength. Subjectivism is scary whenever subjects cannot be trusted, but humans have stumbled on effective pragmatic solutions to the problem of trustworthiness. The refinement of ideals can be treated carefully, i.e. democratically and peacefully and thoughtfully. In any case it's better than having ideals that never improve because of faux objectivity: "That's just the way it is."