I started my academic career in literature, specifically post–World War II American science fiction. In the literature departments I traveled through, SF was a curiosity, a genre that everyone seemed to accept the presence of, but that not many scholars took seriously. Sure, Mary Shelley might be the mother of SF, and, yes, Edgar Allan Poe’s article “The Balloon-Hoax” may have represented the earliest example of speculative fiction, but SF as a serious object of analysis seemed like pure fantasy.

It came as a surprise when I moved into anthropology and was surrounded by people who took SF very seriously. Anthropologists struck me as deeply interested in the kinds of counterfactuals and sheer flights of fancy that SF made possible. Everyone wanted to tell me that Ursula Le Guin was the daughter of anthropologists, yet no one wanted to talk about Doris Lessing’s postcolonial Canopus in Argos sequence of novels. What was going on here? Why, in literary studies, was SF so trivial, while in anthropology it seemed so vital? The answer, I suggest, lies in the project of anthropology and its methodological insufficiency to answer the questions it poses. In the context of literary studies, SF is just another genre—and, like all genre literature, is tarred with its history of being popular. But for anthropologists, SF provides a natural laboratory that has long been the basis of the cross-cultural ethnographic project.

Consider Hal Clement’s quasi-canonical essay “Whirligig World,” in which he lays out his development of the world for his 1953 novel Mission of Gravity. Clement describes the physical properties of Mesklin, a supergiant planet with a fast rotation. The result is gravity three times that of Earth’s, which is no problem for the indigenous life forms but a real problem for the human spacefarers who find themselves stranded there. What kind of life could live in a setting like that? That speculative question is at the heart of Clement’s project and arguably all conjectural fiction, whether fantastic, scientific, or speculative. Anthropologists, similarly, ask what kinds of life do exist in a setting like that—cross-culturally, historically, and at various scales—thereby providing the basis for the anthropological imagination.

But SF and anthropology part ways when we consider that conjectural fictions are unfettered from the historical conditions in which ethnography finds itself mired. Where ethnography—and anthropology more generally—is descriptive and diagnostic, SF operates in three idioms: extrapolation, intensification, and mutation. There are particular powers to each of these approaches, and contributors to this series have used each in particular ways.

Extrapolation imagines what would happen if a present thing—some institution, practice, or people—were to survive into the future relatively unchanged. Octavia Butler’s Parables series, discussed by Priya Chandrasekaran and David Colón-Cabrera, is a prime example of this. Butler extrapolates from the racist, patriarchal neoliberal order of the United States in the 1990s to imagine what will happen if this continues. The results are terrible, and the strength of Butler’s speculative powers lies in her ability to extrapolate a United States that accords with readers’ sensibilities (not to mention time-proven accuracy).

Extrapolation can also work in reverse, as SF writers imagine what will happen in the future, depict it, and in so doing provide intellectual blueprints for the development of modern technologies. This is the well-wrought case of Robert Heinlein’s “pocketphone” in his 1948 novel Space Cadet, which seemingly laid the basis for smartphones and tablets like Sally Applin’s tricorders. When extrapolations are predictive, they can be illuminating and exciting; when they fail, we ignore them.

Intensification takes present forces and magnifies them to imagine their possible effects. J. G. Ballard’s 1962 novel The Drowned World is an exemplary case, in which Ballard imagines what would happen as a result of global warming. With temperatures at the equator reaching 120°F, ice caps fully melt, tundra thaws, oceans rise, cities flood, and populations are displaced to circumpolar communities. Ryan Anderson and Nandita Badami provide examples of these ways of conjectural thinking, particularly in the context of policy development and implementation. What if green technologies lay the basis for new state formations? What if climate change continues apace? Because intensifications rely on familiarity, they provide ways to tinker with the future and its forces.

Mutation is always the most surprising conjectural form, as it attempts to radically unsettle the suppositions of reality with an unconventional “what if?” Alien invasion narratives, such as William Lempert’s, are a prime example of such an approach. They try to imagine what conditions would prevail if something radical happened. This something might be historical, as in Robert Sawyer’s Neanderthal Parallax series where Neanderthals do not go extinct, or it might unfold in the present or near future, resulting in a break from history and its apparent trajectories. Michael Oman-Reagan, Elizabeth Reddy, and Patricia Markert and Jeremy Trombley all provide examples of authors and interlocutors who are thinking through mutation: catastrophic natural disasters, dramatic societal reorganizations, alien worlds, and Twilight Zone experiences. These estrange audiences through their reliance on both deeply felt realities and speculative disruptions, thereby offering a way to deterritorialize the present and bring new futures into being.

The necessary tension between SF and anthropology, much like David Valentine’s discussion of the use of SF as evidence for Elon Musk and his detractors, is that anthropologists want SF to serve as evidence of other forms of life and alternative everyday orders. A friend told me that she was using Le Guin’s The Left Hand of Darkness in a class on the cross-cultural study of gender. I was a little stumped. “Why?” I asked, knowing that a week or two of talking about Le Guin’s novel would cut into the time that could otherwise be spent reading actual evidence of alternative gender structures in real societies on Earth. We agreed that SF can serve as a way into otherwise difficult topics, and yet that doesn’t quite resolve the question for me.

Maybe I’m a prude, but it strikes me that as a social science, anthropology should be wary of SF precisely because it is science fiction and not social science. This is not to deny the powers of speculation, but to warn against them. Speculation can be seductive, can provide different ways of seeing (as Taylor Nelms suggests), but anthropologists should never—even tacitly—accept fiction as evidence of ethnographic realities.