There is a branch of science fiction – some would say it’s the branch which actually defines the genre – known as “hard science fiction”. Like all the terms associated with sf, its meaning is confused, confusing, disputed and not always useful. Wikipedia, for instance, defines hard sf as science fiction which is “characterized by an emphasis on scientific or technical detail, or on scientific accuracy, or on both”. Yet this is not what I’ve always understood by the term.
To me, hard sf has always been that mode of science fiction which features, or emphasises, the “hard” sciences – physics, cosmology, chemistry, etc. This is in contrast to soft sf, which focuses on the “soft” sciences – anthropology, psychology, archaeology, etc. The fact that two such intersecting definitions for the same thing exist is not unusual in science fiction. Indeed, the genre itself has never been satisfactorily defined.
Yet I also believe that hard sf needs to be rigorous. And Wikipedia’s definition (taken from The Encyclopaedia of Science Fiction) does indeed focus on that. But some fictions which would be excluded from the label using Wikipedia’s definition I would still describe as hard sf. Indeed, the classic example given for the sub-genre is often Hal Clement’s Mission of Gravity. Which features aliens and, by implication, faster-than-light travel. Neither concept is “scientifically accurate” in the most rigorous sense of the phrase. Clearly, the definition is problematical.
Categorising a fiction by the sciences which feature in it, hard or soft, is no better. Both types may be present. And if they exist in equal measure, is the fiction hard or soft? And which science is hard and which soft? In order to define hard sf, you must first define the hard sciences. So that’s not going to work either.
And then I came across this…
There’s an interesting article here on the Cosmos Magazine website about humanity’s future in space – or rather, lack of a future. Much of the author’s discussion revolves around the limitations placed on rocketry by chemistry. Rocket engines have not substantially changed for almost a century, and that’s because there’s very little that can be done to improve what is, at its most basic, a chemical reaction. The laws of chemistry dictate how much energy that reaction can generate, and those laws are not something that can be changed. This seems counter-intuitive because in so many other areas of science and technology progress is rapid and effective – computing, for example. But, as the author of the piece writes, “In the case of electronics and information systems, we are dealing with soft rules, related to the limits of human ingenuity. In the case of space flight, we are dealing with hard rules, related to the limits of physics and chemistry.”
Science fiction often has to sidestep such “hard rules” in order to tell a story. The aforementioned faster-than-light travel is a good example. The laws of physics are quite clear that the speed of light cannot be exceeded. There are theoretical ways around this, but most are either impossible or unlikely – Alcubierre’s drive, for example, would require more energy than is available in the entire universe.
So perhaps we should consider sf which stays within the boundaries of these hard limits as hard science fiction. Any fiction which requires authorial invention to circumvent these limits would thus be “soft” sf – or whatever other sub-genre its characteristics identify it as, such as space opera.
Admittedly, it’s not as if a new, or more accurate, definition of hard sf is demanded. Most genre readers and commentators are quite happy with shifting, amorphous and evolving genre categories. Others insist that science fiction is resistant to taxonomy; or even that taxonomy itself is not useful in genre conversations. But taxonomy does indeed have its uses – it allows people to compare like with like, it sets the terms of reference for discussions, it allows for commentary on thematic similarities. And my new definition at least has the benefit of being “hard” itself: we know the hard limits imposed on us by the laws of the universe, and we can recognise those concepts and conceits invented by the author to circumvent those limits.
And it does seem fitting that hard sf should be definable, that it should operate within clearly-drawn boundaries, that its definition should be as rigorous as those fictions which comprise it.