Vonnegut's works have, at various times, been labeled science fiction, satire and postmodern. He also resisted such labels, but his works do contain Common tropes that are often associated with those genres. In several of his books, Vonnegut imagines alien societies and civilizations, as is Common in works of science fiction. Vonnegut does this to emphasize or exaggerate absurdities and idiosyncrasies in our own world. Furthermore, Vonnegut often humorizes the problems that plague societies, as is done in satirical works. However, literary theorist Robert Scholes noted in Fabulation and Metafiction that Vonnegut "reject[s] the traditional satirist's faith in the efficacy of satire as a reforming instrument. [He has] a more subtle faith in the humanizing value of laughter." Examples of postmodernism may also be found in Vonnegut's works. Postmodernism often entails a response to the theory that the truths of the world will be discovered through science. Postmodernists contend that truth is subjective, rather than objective, as it is biased towards each individual's beliefs and outlook on the world. They often use unreliable, first-person narration, and narrative fragmentation. One critic has argued that Vonnegut's most famous novel, Slaughterhouse-Five, features a metafictional, Janus-headed outlook as it seeks both to represent actual historical events while problematizing the very notion of doing exactly that. This is encapsulated in the opening lines of the novel: "All this happened, more or less. The war parts, anyway, are pretty much true." This bombastic opening – "All this happened" – "reads like a declaration of complete mimesis" which is radically called into question in the rest of the quote and “[t]his creates an integrated perspective that seeks out extratextual themes [like war and traumra] while thematizing the novel's textuality and inherent constructedness at one and the same time.” While Vonnegut does use elements as fragmentation and metafictional elements, in some of his works, he more distinctly focuses on the peril posed by individuals who find subjective truths, mistake them for objective truths, then proceed to impose these truths on others.