Sample of granite. © 2024 Raymund Eich

A Science Fiction Hardness Scale

Some thoughts on a science fiction hardness scale, including numerous examples drawn from the work of Larry Niven. Plus, is Niven as hard a science fiction writer as we tend to think?

One of my strongest memories of junior high school is of failing a science test.

Good grades were my norm. In particular, good grades in science were my norm. Especially because I was a hardcore science fiction fan by eighth grade, and if you love science fiction you should love science.

What happened on the test I failed? Unlike a normal test, which involved decoding input symbols, performing mental processes on those symbols, and outputting other symbols, the inputs were completely different. The test was on the geology unit in science class. For this, Mr. Page set up samples of different minerals. Our task: identify them.

I totally bombed it. Not just below D tier, but below 50% right. Ouch!

(Which was my first indication that bench science was not where my strengths lay and I would only prosper in a career that manipulated symbols instead of objects. Unfortunately, it took me another ten years to figure that out).

What we most remember

But, as we all know, we more likely remember the one thing that went wrong instead of the hundred things that went right. Same here. I remember that geology test more than almost any other test in middle school. Not just the shock of the low grade, but also the frustration. I followed the rules for determining where minerals landed on the Mohs scale! I always used my fingernail to scratch the mineral and not the other way around!

Thus, for the longest time, I exiled geology in general, and the Mohs scale in particular, from my mind. (Hey, even if you love science, there must be some science you love the least. Geology was it for me).

But the Mohs scale is a useful metaphor for thinking about the hardness of something much more important than minerals.

A science fiction hardness scale

One of the perennial debates in science fiction is between advocates of hard science fiction and soft science fiction. How does the Mohs scale help us think about the hardness of sci fi stories and novels?

The Mohs scale assigns hardness to minerals, not elements

Consider carbon. One of its solid forms, graphite, has a Mohs hardness of 1-2. Another solid form, diamond, has a Mohs hardness of 10 and was the hardest substance known when Friedrich Mohs introduced his scale over two centuries ago.

By analogy, a science fiction hardness scale assigns hardness to stories and novels, not to authors as a whole. Larry Niven’s work ranges from the Bussard ramjet STL setting of The State (as seen in the opening chapters of A World Out of Time and in the backstory to The Integral Trees), to the hyperdrives-plus-stasis-fields-plus-reactionless-drives-plus-psi of Known Space, to the time travel/fantasy humor of the Svetz stories in Flight of the Horse, and the pure fantasy of The Magic Goes Away series.

Ranking those Niven works from hardest to softest on 1 to 10 scale, we could put A World Out of Time/Integral Trees at 9, Known Space at 6, Svetz at 2, and the Magic Goes Away at 1. You other Niven fans out there might quibble with the exact numbers, but you’ll agree I’m in the ballpark.

The Mohs scale assigns hardness to minerals, not rocks

Consider granite. It’s a rock made of several minerals, as you can see in the photo of a granite sample. Those minerals can vary in hardness.

Sample of granite. © 2024 Raymund Eich

Perhaps a better approach is a science fiction hardness scale that assigns hardness to aspects of stories and novels instead of novels as a whole.

Go back to A World Out of Time. Niven sticks to the known rules of STL, particularly time dilation, to send Jaybee Corbell on a journey of multiple millions of years (Earth reference frame). Even if the interstellar medium near Sol lacks enough hydrogen for Bussard ramjets to work, what Niven did with the concept is a pretty solid 10.

Of course, in Niven’s novel, Corbell was trained to pilot the relativistic ramjet after receiving injections of memory RNA. Though memory RNA hasn’t been conclusively disproved, Niven’s use of it was highly speculative. Do we call that a 6? an 8?

On top of that, in A World Out of Time, Niven postulated a couple of different forms of indefinite life extension, including one dependent on machinery that had been idle for thousands of years. This seems really implausible. (Imagine a car that sat in a garage for a decade. Would it start up in seconds and be ready to drive?). Where does the life extension in A World Out of Time land on our scale? A 3? A 4?

The reverse is true, too

Flipping the concept, you can have nuggets of hardness in the softest of fantasy. The premise of The Magic Goes Away is that magic requires mana, which is a substantially non-renewable resource. (At least on the timescale of average human lifespan). The et in Arcadia ego feeling of The Magic Goes Away stories, and the hopefulness of The Magic May Return stories (such as Roger Zelazny’s entry, “Mana From Heaven”), both depend on the premise Niven laid down in the late ’60s and never violated.

That said, no one reads just the memory RNA or the life extension aspects of A World Out of Time in isolation. Just like no one expects a granite countertop to be a single mineral with no grain or texture. Thus, while a science fiction hardness scale might conceptually be applied to particular aspects of a story, it makes more sense to apply it to a story as a whole.

Which ties into how the Mohs scale is used today, as a rough-and-ready, in-the-field guide to mineral identification, not a detailed materials science analysis of all the subcomponents of an aggregated material.

The Mohs scale describes what is, not what ought to be

Let’s go back to carbon. Diamond is better than graphite, right?

It depends. If you’re about to propose to your girlfriend or you’re manufacturing a bit to drill for oil, diamond might be your best friend.

But if you need to write a note on a piece of paper, only graphite will take care of you. Diamond will leave you with shreds of formed dehydrated wood pulp.

Similar thinking applies with any kind of science fiction hardness scale.

Some people want stories where the science fiction content is in the background. We came out of FTL near Alpha Centauri B III and landed at the spaceport ten minutes later followed by the actual story.

Some people want detailed descriptions. Not just of the laser sails, but getting down to cost/benefit analysis of throwaway mirrors vs. tractor beams for interstellar travel.

The problem for any reader is not that thousands of sf titles are in regions of the science fiction hardness scale they don’t enjoy. The only problem is finding stories in the regions they do enjoy.

To sum up, a science fiction hardness scale’s primary purpose is to help readers find the books they want. Nothing else matters.

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