Rediscovering Hard Science Fiction — and Why Science Fantasy Scratches a Different Itch

For a long time, I drifted away from hard science fiction—or, more precisely, from the kind of science fiction in which a speculative idea is not merely part of the scenery but the engine of the story.

Then, in 2024, I picked up Greg Egan’s Permutation City, and something clicked back into place. The same part of my brain that lit up when I was young and reading Arthur C. Clarke’s 2001: A Space Odyssey or Rendezvous with Rama suddenly woke up again.

There is nothing quite like that particular flavour of science fiction: big ideas, unnerving thought experiments and stories in which the central engine of wonder is thought itself. Charles Stross’s Glasshouse gave me that feeling. So did Hannu Rajaniemi’s The Quantum Thief.

Plenty of other books marketed as science fiction were enjoyable, but they were asking something different of me. They offered space wizards, interstellar empires or fantasy tropes wearing chrome-plated armour. There is nothing inherently wrong with any of that. It simply does not scratch the same itch.

Cover images: Glasshouse by Charles Stross, published by Ace; Permutation City by Greg Egan, published by HarperPrism; and The Quantum Thief by Hannu Rajaniemi, published by Tor Books. Used here for purposes of review and commentary.

Hard Science Fiction and Idea-Driven Science Fiction

Hard science fiction and idea-driven science fiction are not quite the same thing. Hard SF generally promises particular attention to scientific or technical plausibility. Idea-driven SF may begin with a more speculative assumption, but then treat that assumption seriously and pursue its consequences.

The books I had been missing tend to occupy the overlap. Their science may be speculative, sometimes extremely so, but it is not merely decorative. Remove the central idea and the story collapses.

Permutation City, for example, is not simply a thriller that happens to contain uploaded minds. Its questions about copied consciousness, simulated worlds and the relationship between computation and reality are the story. The characters exist partly to test those ideas, and the ideas become unsettling because the book refuses to stop at their most convenient implications.

I later returned to one related question—the possibility that the future might be shaped not by alien artificial intelligences but by the social consequences of copied human minds.

Science Fantasy Is Not Failed Science Fiction

A great deal of modern speculative fiction combines technological settings with magical or metaphysical systems. The usual term is science fantasy, although the boundary is porous.

Tamsyn Muir’s Locked Tomb series is a good example. Its necromantic empire, planetary houses and decaying space civilisation are inseparable from one another. The books could not simply lose the interplanetary setting and remain unchanged. Yet their central causal machinery is magical, theological and mythic rather than an extrapolation from known science.

C. S. Friedman’s Coldfire Trilogy sits differently on the same border. Its world began as a human colony, but the force that shapes reality responds to thought, fear and belief. The science-fictional origin matters, while the stories that emerge from it often behave like dark fantasy.

This is not criticism. Some of my favourite books belong somewhere in this territory. The distinction matters because the works establish different expectations. Hard SF invites the reader to examine how an idea might work. Science fantasy may be more interested in what an impossible power means.

Where the Combination Loses Me

My difficulty begins when a story wants scientific credibility and magical freedom at the same time, without establishing any shared logic between them.

I do not require every speculative mechanism to be possible. I do want to understand what kind of scrutiny the story expects me to apply. If propulsion, biology and computation are treated as systems with constraints, while a neighbouring magical power can solve problems whenever the plot requires it, the asymmetry becomes difficult to ignore.

Arthur C. Clarke’s Third Law tells us that “any sufficiently advanced technology is indistinguishable from magic.” But this is an observation about perspective. A person who does not understand a technology may interpret it as supernatural.

It does not follow that anything described as magic automatically becomes plausible technology. The unknown mechanism still needs to behave like a mechanism: it must have limits, consequences or at least enough consistency that the reader can form expectations.

When the Uncertainty Is the Point

Some books make the uncertainty between science and magic part of their atmosphere. Gene Wolfe’s The Book of the New Sun initially resembles fantasy, but its apparently medieval world contains remnants of a technological past so remote that neither the characters nor the reader can always interpret them correctly.

Jack Vance’s Dying Earth stories also combine forgotten science, elaborate magic and civilisations living among the ruins of knowledge they no longer fully command. They do not reduce every wonder to a concealed machine. Instead, they make the inability to draw a clean boundary part of the world’s decay.

That works for me because the ambiguity is consistent. The characters inhabit a reality in which knowledge has fragmented, and the reader shares their uncertainty. The books do not switch opportunistically between scientific explanation and magical exception; they build worlds where the distinction itself has become unreliable.

Why I Still Prefer Star Wars to Star Trek

Given all this, it may seem contradictory that I generally prefer Star Wars to Star Trek. Neither is hard science fiction, and both rely on impossible technologies. Yet I approach them differently because they make different promises.

Star Wars presents itself openly as mythic adventure. The Force is spiritual and magical. Its planets, ships and empires provide the setting for a story built from archetypes, family conflict, temptation and redemption. I do not expect hyperspace to survive technical examination because the films rarely ask me to examine it that way.

Star Trek, by contrast, often speaks in the language of science, explanation and problem-solving. Its speculative machinery is equally fictional, but the programme frequently invites the audience to think about how systems operate. When the explanation becomes convenient hand-waving, I notice it more because the story has encouraged me to care.

The difference is not really that films ask for fast feeling while books invite slow thought. Films can be intellectually rigorous, and novels can run entirely on momentum. The difference is the contract established by the individual work.

Returning to the Big Ideas

That may be why Permutation City affected me so strongly. It reminded me how powerful science fiction can be when it chooses a premise and follows it all the way down—past the technological novelty and into questions about identity, reality and what counts as a human life.

It also reminded me that there is room—pun unavoidable—for all of it: hard SF that bends the brain, fantasy hidden inside a spacesuit and space opera that has no interest in obeying physics.

The categories are not rankings. They are signals about where a story expects the reader to look closely. Some stories ask whether a technology could work. Others ask what a miracle would do to the people who possess it.

Every once in a while, however, I want to return to the books in which the thought experiment is not merely a source of atmosphere. It is the true protagonist.