Although the narrative of Stranger in a Strange Land operates on many different levels, one obvious interpretation of Mike's story would be as a postmodern retelling of the Jesus story. Before the novel even begins, we see that the title of Part One is "His Maculate Conception," a satirical reference to the mythology of Christ's immaculate conception. Although Mike's biological parents are entirely human, hence his conception being "maculate" rather than immaculate, Mike's birth and childhood on Mars make his origin as unique on Earth as Christ's. Like Christ, Mike begins to preach a message of peace and love to mankind, attracts followers. Mike's "ninth circle" is roughly equivalent to Christ's disciples, and he is persecuted by the Earthling institutions that seek to preserve their status quo at any cost. Mike is aware of his parallels to Jesus, so when he allows himself to be murdered at the end of the novel, he quite self-consciously engineers his death to reference Christ's, even positioning himself to be struck by the light in such a way that it appears he has an angelic halo.
As soon as Mike is discovered on Mars, he is subjected to the wills of massive Earth institutions. He is brought back to Earth and put in a hospital where he is ostensibly being observed and cared for. In fact, he is a de facto prisoner of Secretary General Douglas and his administration, who know that Mike's political importance, as a celebrity, a man of enormous wealth, and arguably the owner of planet Mars, is too great for them to allow him freedom. At one point Douglas considers murdering Mike to preserve his own political power. Any institution has a tendency toward self-preservation, but Heinlein demonstrates here that that tendency is often allowed to override basic morality. This is just as true of the Fosterite church as it is of the government, and the Fosterites of course are supposed to be, at their root, upholders of morality and goodness. And yet, though Jubal teaches Mike to mistrust institutions, Mike discovers that he needs to build an institution of his own, the Church of All Worlds, modeled largely on the Fosterites, in order to reach the public.
In his time on Earth, Mike slowly learns about his own race, and what characteristics define humankind. The narrator tells us early on that the single most important difference between human beings and Martians is that Martians lack bipolar (male/female) sexuality. By the end of the novel Mike has come to believe that sexuality, and the sexual act, are the greatest gift that belongs to humanity. Mike's first notion of intimacy, learned on Mars, is the act of "water-sharing" or drinking from the same glass as another. From there, Mike learns the human act of kissing, its own sort of water-sharing. Soon enough Mike discovers sex, the ultimate "growing-closer." He believes that the mental bond shared between lovers during sex is the deepest "grokking" known to man.
Throughout the book, the narration often steps back from the daily concerns of its characters and plot mechanics to tell us about seemingly unrelated events on Earth and Mars. Sometimes this cosmic viewpoint takes in centuries of histories in a few sentences, other times it tells us of minor events. Almost always this viewpoint is employed at the beginnings of chapters. Narration that can shift so easily and nonchalantly from a massive historical perspective to focusing on minutiae strewn across the galaxy would seem to represent a perspective that only a God-like figure could have. By regularly telescoping out from the concerns of Mike's story to show us what is afoot throughout the cosmos, Heinlein gives us a sense that a higher power is observing events unfold. This notion is reinforced by the inclusion, in Chapter XXV, of Heaven amongst the novel's scheme of locales. Though omniscient narration is conventional in much fiction, Heinlein boosts omniscience to an absurd level by allowing his readers equally clear vision of Earth and Mars, history and trivia, the physical and the metaphysical. It is almost as if Heinlein had taken Mike's credo—"Thou art God!"—as an imperative for his narrative voice.
Most of the novel's story unfolds in dialogue, and the majority of its philosophical theses are proposed within conversations. Though most of these conversations occur between friends, and there is a good deal of kidding and friendliness interspersed throughout, the bulk of their discussion is about serious matters—politics, religion, individual responsibility, love, and the nature of man. Jubal Harshaw, particularly, has a tendency to engage in conversations wherein he posits a philosophy that surprises his companion, and then Jubal sets about steamrolling the companion with his wisdom. As a former lawyer, and practicing fiction writer, Jubal is adept at using rhetoric to advance his theories about life. Much of the entertainment value of the novel comes from the witty, compelling ways Jubal couches his arguments.
The Martian ways of thought, we are told, are entirely foreign to our own. Since we know that we could never truly understand them, the Martians remain extremely mysterious throughout the book. Nonetheless, a few Martian concepts do seem to be roughly translatable into English, and they become mantras for both Mike and his followers. First and foremost of course is "grok," the one genuinely Martian word that can be said and understood in English. The basic meaning is "understand deeply," though as Mahmoud explains in Chapter XXI, it has many applications and connotations in the original Martian. By giving us this foreign word and suggesting that it has deeper meanings than we can fully appreciate, Heinlein cleverly allows us to invest our own meaning into "grok," and by extension the Martian mindset. Other Martian-like phrases that Mike popularize include "I am just an egg," "waiting is," and the ubiquitous "Thou art God!"
"Grokking" has multiple meanings in the Martian language, but over the course of its usage in the novel, it tends to represent an understanding between two people, or a person and an object, or a person and an idea, so deep as to be equivalent to a psychic bond. When Mike groks that grass is meant to be walked on, he is not understanding an abstract concept but rather communing with the grass and feeling what it feels. Grokking soon comes to be synonymous with Mike's notion of God: a cosmic understanding that runs through all things and people and unifies the universe.
Jubal is an aficionado of sculpture, and in Chapter XXX he takes Ben on a tour of his sculpture garden. He is particularly fond of two Rodin sculptures and a sculpture of Hans Christian Andersen's "Little Mermaid." Rodin's "La Belle Heaulmière" represents to Jubal the bittersweet tragedy of female aging, and perhaps his own conflicted feelings about his own aging. Rodin's "Caryatid Who Has Fallen under Her Stone" represents courage and victory in ostensible defeat—a direct parallel to Mike's sacrifice at the end of the novel. Finally, "The Little Mermaid" is a mermaid who chooses to live on land, and thus a "stranger in a strange land" who nobly endures the pain her decision has brought, just like Mike's choice to immerse himself in human society.
Heinlein never makes it entirely clear whether his portrayal of Heaven—a humorous combination of traditional halo-and-wings angelic imagery with the structure of a corporation, with God as a boss expecting results from his employee angels—is meant to be taken literally or metaphorically. Heinlein implies that, like any religious assertion, it needs to be able to be understood both literally and metaphorically. So although it may seem counterintuitive that men like Foster and Digby, both of whom have committed multiple and grave sins in their lives on Earth, would be allowed into Heaven. On the other hand, the narrative suggests that it is their continuing influence on Earth among the many passionate Fosterites, that makes them as angels watching over the Earth. As angels, they literally influence Earth occurrences, and as deceased leaders who teachings continue to affect history, they metaphorically wield influence. When Mike joins their company at novel's end, we know that his impact on Earth culture will be lasting.
The summary incorrectly states that Apollo is the Greek "word" for Mars. Actually, Ares is the Greek name for the god known as Mars in Latin.
Apollo is one of the few classical gods known by nearly the same name in Greek and Latin. In English, he is called Apollo in both contexts.