Science fiction is often about amazing technology. Huge spaceships, amazing cities, holograms, antigravity…
Some of this futuristic tech, such as fusion reactors, direct neural implants, fullerene cable, and Hard AI, will certainly be here in the next few decades. Other tech, such as matter printing, vat grown meat, flying cars, rail guns, and smart glasses, are here now, and just have to catch on (matter printing is already mainstream), or be refined. And some futuristic tech, such as the Internet predicted by Vernor Vinge and William Gibson, is already so familiar we wonder how we could have lived without it.
On the other side is all manner of space opera tech like blasters, gravity plates, and matter teleportation above the quantum level, that is patently ridiculous. Or is it?
When it comes to super-advanced science fiction (whether SF or scifi) tech, there are four conditions that might determine whether it will one day be possible or not. These are handwavium, unobtanium, clarketech, and sillytech.
Unobtanium – sometimes confused with handwavium (for example on-line dictionaries, e.g. Wiktionary which I here quote), unobtanium is, as its name implies, any hypothetical but unobtainable material with desirable engineering properties. An example of Unobtanium is negative matter (also called Exotic Matter). If we had negative matter, we could make an Alcubierre warp drive engine. But we don’t, so we can’t.
Handwavium refers to any as yet undiscovered theory or law of physics, or an extension of known laws and the application thereof, that will make it possible to do amazing things. For example, graviton manipulation that makes it possible to build cheap and reliable gravity plates that would allow spaceships to exactly mimic surface-going vessels by making down perpendicular to the direction of travel, and that are so robust that they are always the last system to fail on a crippled spaceship). Or anything else in SF/scifi that is required to get the story happening. In the excellent TV Tropes website, it is known as Applied Phlebotinum and compared with Author Powers, Hand Wave, MacGuffin, Deus ex Machina, and A Wizard Did It.
Sillytech is similar, but differs from Handwavium in that there is no attempt to even explain things. The tech just works, as if by magic (or more precisely, by applied phlebotinum). For example, Iron Man’s rockets allow him to fly into outer space, or lift entire buildings, even through there is no explanation for where the reaction mass comes from, or how Tony Stark isn’t burnt to a crisp because of the heat from the rockets. Or, still on the subject of waste heat, how Star Wars can have 20 gigaton turbo lasers. Even if this operates at a hypothetically near perfect 99.9% thermal efficiency, the remaining 0.1% equals a 20 megatons of waste heat. A single shot of its own turbo laser would quite easily reduce the entire Star Destroyer to slag. This is why superheroes and cinematic space opera always tend to score so low on the Sliding Scale of Scientific Hardness. Munchkins tend to have a weakness for sillytech, since it allows for cartoonishly powerful weapons. I coined the neologism when I was involved in the Orion’s Arm Worldbuilding Group, back in 2000.
Clarketech I also came up with “Clarketech” at the same time as I coined Sillyetch, though I suspect in this case others may have done likewise, as its an obvious SFna; word. It’s based on Arthur C Clarke’s Third Law: “Any sufficiently advanced technology is indistinguishable from magic.” For example, the monoliths in 2001 act in an incomprehensible way. Or to a CroMagnon Man, a TV set is magic. Or electricity and telephones (Or as Catweazle called them “electrickery” and “telling bone“). Clarketech as I use it in my worldbuilding refers to tech and artifacts from inconceivably advanced alien races or trans-singularitan civilisations. A subset of Clarketech is Godtech, when the technology is so advanced and potent as to be godlike.
Although Clarketech and Sillytech may have similar capacities, in that both are equally “magic”, Clarketech is actually based on handwavium and unobtanium from an inconceivably more advanced civilisation, about the same degree above us as we are above bacteria. It is justified because it is created by beings that might as well be gods (or Gods). What makes sillytech silly is that it is ordinary humans that invented and use it. Rather than being a symbol of the miraculous and the numinous, it is just lazy writing, and it flattens the storytelling and worldbuilding by removing any sense of the imaginal, the uncanny and the numinous.