Heinlein's books probe a range of ideas about a range of topics such as sex, race, politics, and the military. Many were seen as radical or as ahead of their time in their social criticism. His books have inspired considerable debate about the specifics, and the evolution, of Heinlein's own opinions, and have earned him both lavish praise and a degree of criticism. He has also been accused of contradicting himself on various philosophical questions.
Brian Doherty cites William Patterson, saying that the best way to gain an understanding of Heinlein is as a "full-service iconoclast, the unique individual who decides that things do not have to be, and won't continue, as they are." He says this vision is "at the heart of Heinlein, science fiction, libertarianism, and America. Heinlein imagined how everything about the human world, from our sexual mores to our religion to our automobiles to our government to our plans for cultural survival, might be flawed, even fatally so."
The critic Elizabeth Anne Hull, for her part, has praised Heinlein for his interest in exploring fundamental life questions, especially questions about "political power—our responsibilities to one another" and about "personal freedom, particularly sexual freedom."
Edward R. Murrow hosted a series on CBS Radio called This I Believe, which solicited an Entry from Heinlein that is probably the most enduring and popular of the title: Our Noble, Essential Decency. In it, Heinlein broke with the normal trends, stating that he believed in his neighbors (some of whom he named and described), community, and towns across America that share the same sense of good will and intentions as his own, going on to apply this same philosophy to the US, and humanity in general.
I believe in my fellow citizens. Our headlines are splashed with crime. Yet for every criminal, there are ten thousand honest, decent, kindly men. If it were not so, no child would live to grow up. Business could not go on from day to day. Decency is not news. It is buried in the obituaries, but it is a force stronger than crime.
At the time I wrote Methuselah's Children I was still politically quite naive and still had hopes that various libertarian notions could be put over by political processes ... It [now] seems to me that every time we manage to establish one freedom, they take another one away. Maybe two. And that seems to me characteristic of a society as it gets older, and more crowded, and higher taxes, and more laws.
Heinlein's fiction of the 1940s and 1950s, however, began to espouse conservative views. After 1945, he came to believe that a strong world government was the only way to avoid mutual nuclear annihilation. His 1949 novel Space Cadet describes a future scenario where a military-controlled global government enforces world peace. Heinlein ceased considering himself a Democrat in 1954.
When Robert A. Heinlein opened his Colorado Springs newspaper on April 5, 1958, he read a full-page ad demanding that the Eisenhower Administration stop testing nuclear weapons. The science fiction author was flabbergasted. He called for the formation of the Patrick Henry League and spent the next several weeks writing and publishing his own polemic that lambasted "Communist-line goals concealed in idealistic-sounding nonsense" and urged Americans not to become "soft-headed."
That ad was entitled Who Are the Heirs of Patrick Henry?. It started with the famous Henry quotation: "Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery? Forbid it, Almighty God! I know not what course others may take, but as for me, give me liberty, or give me death!!". It then went on to admit that there was some risk to nuclear testing (albeit less than the "willfully distorted" claims of the test ban advocates), and risk of nuclear war, but that "The alternative is surrender. We accept the risks." Heinlein was among those who in 1968 signed a pro-Vietnam War ad in Galaxy Science Fiction.
Heinlein always considered himself a libertarian; in a letter to Judith Merril in 1967 (never sent) he said, "As for libertarian, I've been one all my life, a radical one. You might use the term 'philosophical anarchist' or 'autarchist' about me, but 'libertarian' is easier to define and fits well enough."
Heinlein grew up in the era of racial segregation in the United States and wrote some of his most influential fiction at the height of the civil rights movement. He explicitly made the case for using his fiction not only to predict the future but to educate his readers about the value of racial equality and the importance of racial tolerance. His early novels were very much ahead of their time both in their explicit rejection of racism and in their inclusion of protagonists of color—in the context of science fiction before the 1960s, the mere existence of characters of color was a remarkable novelty, with green occurring more often than brown. For example, his 1948 novel Space Cadet explicitly uses aliens as a metaphor for minorities. In his novel Star Beast, the de facto foreign minister of the Terran government is an undersecretary, a Mr. Kiku, who is from Africa. Heinlein explicitly states his skin is "ebony black", and that Kiku is in an arranged marriage that is happy.
In a number of his stories, Heinlein challenges his readers' possible racial preconceptions by introducing a strong, sympathetic character, only to reveal much later that he or she is of African or other ancestry; in several cases, the covers of the books show characters as being light-skinned, when in fact the text states, or at least implies, that they are dark-skinned or of African ancestry. Heinlein repeatedly denounced racism in his non-fiction works, including numerous examples in Expanded Universe.
Heinlein reveals in Starship Troopers that the novel's protagonist and narrator, Johnny Rico, the formerly disaffected scion of a wealthy family, is Filipino, actually named "Juan Rico" and speaks Tagalog in addition to English.
Race was a central theme in some of Heinlein's fiction. The most prominent and controversial example is Farnham's Freehold, which casts a white family into a future in which white people are the slaves of cannibalistic black rulers. In the 1941 novel Sixth Column (also known as The Day After Tomorrow), a white resistance movement in the United States defends itself against an invasion by an Asian fascist state (the "Pan-Asians") using a "super-science" technology that allows ray weapons to be tuned to specific races. The book is sprinkled with racist slurs against Asian people, and black and Hispanic people are not mentioned at all. The idea for the story was pushed on Heinlein by editor John W. Campbell, and Heinlein wrote later that he had "had to re-slant it to remove racist aspects of the original story line" and that he did not "consider it to be an artistic success." However, the novel prompted a heated debate in the scientific community regarding the plausibility of developing ethnic bioweapons.
Individualism and self-determination
In keeping with his belief in individualism, his work for adults—and sometimes even his work for juveniles—often portrays both the oppressors and the oppressed with considerable ambiguity. Heinlein believed that individualism was incompatible with ignorance. He believed that an appropriate level of adult competence was achieved through a wide-ranging education, whether this occurred in a classroom or not. In his juvenile novels, more than once a character looks with disdain at a student's choice of classwork, saying, "Why didn't you study something useful?" In Time Enough for Love, Lazarus Long gives a long list of capabilities that anyone should have, concluding, "Specialization is for insects." The ability of the individual to create himself is explored in stories such as I Will Fear No Evil, "'—All You Zombies—'", and "By His Bootstraps".
Heinlein claimed to have written Starship Troopers in response to "calls for the unilateral ending of nuclear testing by the United States." Heinlein suggests in the book that the Bugs are a good example of Communism being something that humans cannot successfully adhere to, since humans are strongly defined individuals, whereas the Bugs, being a collective, can all contribute to the whole without consideration of individual desire.
For Heinlein, personal liberation included sexual liberation, and free love was a major subject of his writing starting in 1939, with For Us, The Living. During his early period, Heinlein's writing for younger readers needed to take account of both editorial perceptions of sexuality in his novels, and potential perceptions among the buying public; as critic William H. Patterson has put it, his dilemma was "to sort out what was really objectionable from what was only excessive over-sensitivity to imaginary librarians".
By his middle period, sexual freedom and the elimination of sexual jealousy became a major theme; for instance, in Stranger in a Strange Land (1961), the progressively minded but sexually conservative reporter, Ben Caxton, acts as a dramatic foil for the less parochial characters, Jubal Harshaw and Valentine Michael Smith (Mike). Another of the main characters, Jill, is homophobic.
According to Gary Westfahl,
"Heinlein is a problematic case for feminists; on the one hand, his works often feature strong female characters and vigorous statements that women are equal to or even superior to men; but these characters and statements often reflect hopelessly stereotypical attitudes about typical female attributes. It is disconcerting, for example, that in Expanded Universe Heinlein calls for a society where all lawyers and politicians are women, essentially on the grounds that they possess a mysterious feminine practicality that men cannot duplicate."
In books written as early as 1956, Heinlein dealt with incest and the sexual nature of children. Many of his books including Time for the Stars, Glory Road, Time Enough for Love, and The Number of the Beast dealt explicitly or implicitly with incest, sexual feelings and relations between adults and children, or both. The treatment of these themes include the romantic relationship and eventual marriage, once the girl becomes an adult via time-travel, of a 30-year-old engineer and an 11-year-old girl in The Door into Summer or the more overt intra-familial incest in To Sail Beyond the Sunset and Farnham's Freehold. Heinlein often posed situations where the nominal purpose of sexual taboos was irrelevant to a particular situation, due to future advances in technology. For example, in Time Enough for Love Heinlein describes a brother and sister (Joe and Llita) who were mirror twins, being complementary diploids with entirely disjoint genomes, and thus not at increased risk for unfavorable gene duplication due to consanguinity. In this instance, Llita and Joe were props used to explore the concept of incest, where the usual objection to incest — heightened risk of genetic defect in their children — was not a consideration. Peers such as L. Sprague de Camp and Damon Knight have commented critically on Heinlein's portrayal of incest and pedophilia in a lighthearted and even approving manner.
In To Sail Beyond the Sunset, Heinlein has the main character, Maureen, state that the purpose of metaphysics is to ask questions: "Why are we here?" "Where are we going after we die?" (and so on); and that you are not allowed to answer the questions. Asking the questions is the point of metaphysics, but answering them is not, because once you answer this kind of question, you cross the line into religion. Maureen does not state a reason for this; she simply remarks that such questions are "beautiful" but lack answers. Maureen's son/lover Lazarus Long makes a related remark in Time Enough for Love. In order for us to answer the "big questions" about the universe, Lazarus states at one point, it would be necessary to stand outside the universe.
During the 1930s and 1940s, Heinlein was deeply interested in Alfred Korzybski's general semantics and attended a number of seminars on the subject. His views on epistemology seem to have flowed from that interest, and his fictional characters continue to express Korzybskian views to the very end of his writing career. Many of his stories, such as Gulf, If This Goes On—, and Stranger in a Strange Land, depend strongly on the premise, related to the well-known Sapir–Whorf hypothesis, that by using a correctly designed language, one can change or improve oneself mentally, or even realize untapped potential (as in the case of Joe in Gulf – whose last name may be Greene, Gilead or Briggs).
The term "pay it forward", though it was already in occasional use as a quotation, was popularized by Robert A. Heinlein in his book Between Planets, published in 1951:
The banker reached into the folds of his gown, pulled out a single credit note. "But eat first—a full belly steadies the judgment. Do me the honor of accepting this as our welcome to the newcomer."
His pride said no; his stomach said YES! Don took it and said, "Uh, thanks! That's awfully kind of you. I'll pay it back, first chance."
"Instead, pay it forward to some other brother who needs it."
Heinlein was a mentor to Ray Bradbury, giving him help and quite possibly passing on the concept, made famous by the publication of a letter from him to Heinlein thanking him. In Bradbury's novel Dandelion Wine, published in 1957, when the main character Douglas Spaulding is reflecting on his life being saved by Mr. Jonas, the Junkman:
How do I thank Mr. Jonas, he wondered, for what he's done? How do I thank him, how pay him back? No way, no way at all. You just can't pay. What then? What? Pass it on somehow, he thought, pass it on to someone else. Keep the chain moving. Look around, find someone, and pass it on. That was the only way ...
Bradbury has also advised that writers he has helped thank him by helping other writers.
Heinlein both preached and practiced this philosophy; now the Heinlein Society, a humanitarian organization founded in his name, does so, attributing the philosophy to its various efforts, including Heinlein for Heroes, the Heinlein Society Scholarship Program, and Heinlein Society blood drives.
Author Spider Robinson made repeated reference to the doctrine, attributing it to his spiritual mentor Heinlein.