Besides writing commandments I don't think C. S. Lewis and Robert Heinlein had much in common.
Ferinstance, I don't see Lewis ever really grokking Stranger In A Strange Land. Nor do I think Heinlein would get much out of Perelandra. Yet in these differences, we see commonalities: both fellows wrote well and knew how good writing works.
And here are C. S. Lewis' 5 Commandments for writing for the reader's edification.
- Always try to use the language so as to make quite clear what you mean and make sure your sentence couldn’t mean anything else.
- Always prefer the plain direct word to the long, vague one. Don’t implement promises, but keep them.
- Never use abstract nouns when concrete ones will do. If you mean “More people died” don’t say “Mortality rose.”
- In writing. Don’t use adjectives which merely tell us how you want us to feel about the thing you are describing. I mean, instead of telling us a thing was “terrible,” describe it so that we’ll be terrified. Don’t say it was “delightful”; make us say “delightful” when we’ve read the description. You see, all those words (horrifying, wonderful, hideous, exquisite) are only like saying to your readers, “Please will you do my job for me.”
- Don’t use words too big for the subject. Don’t say “infinitely” when you mean “very”; otherwise you’ll have no word left when you want to talk about something really infinite.
When Shakespeare wanted to show someone to be an ass he never did so as effectively as with his character Dogberry in Much Ado About Nothing. This character was prone to malapropisms. Don't be this guy. You want to be the anti-Dogberry.
I write poorly when I don't have a clear idea in my head of what I want to convey. This clear idea needs to get out of my noggin and into yours. Since you're not telepathic, I have to use words to express my ideas in a way that your thinking matches my clear idea.
1. Words can be slippy things. It's easy to write something that can be construed differently from what you intend. You can't just get each word's denotation correct, but you must string all the words together in a manner that straightforwardly conveys your intent. You can't just shrug when a sentence is unclear. Dammit. Rewrite it until it is clear. Or yank it out until you have not only clarity of thought and intent, but clarity of expression.
2. Words are pills. Dogberry is the ass because he doesn't know one pill from another. Shakespeare's genius is that he is able to give the theater-goer contextual clues to discern what Dogberry intended to say so that when he actually says something wildly inappropriate you get the joke. You discern from context that Dogberry wants to take the larger-pill, but instead he takes the small-pill and incongruity results in a hearty laugh at Dogberry's expense.
A plain, direct word as Lewis recommends in this case is a pill with minimal side-effects. It makes you big or small without making hair grow out of your ears. The long, vague words that Lewis warns us about invariably have side effects built into them. Sometimes you do need to grow ten foot tall with hair growing out of your ears, but those times are not as common as you might think. And instead of seeming smart and stylish, the unintended consequences of the long, vague word end up making you look foolish.
I don't think Lewis is saying never use the long, vague word. Just know all the baggage and side-effects it carries with it and gauge that against your intent. And prefer the simpler generic when it works as well.
3. Lewis advises that when choosing between two nouns, prefer the concrete to the abstract. This is a bigger problem for the academic who writes than for the rest of us. Experts tend to work in the abstract because they can bounce ideas around, manipulate them, and then apply the abstract to a broad spectrum of circumstances. Working in the abstract can be like swimming to the fish. Or it can be like being tossed into the deep end of the pool when you can't swim.
Writing and reading is communication. Whereas some can't work in the abstract, many more folks (if not everyone) can work in the concrete. People tend to remember concrete details better. In urban legend the details provide the touch points that lend internal consistency and believability. These are critical success criteria in writing.
4. Encompasses the old writer's proverb: Show, but don't tell. When I say that the girl is beautiful an event terrible or a song delightful it's a summary. There's nothing for the reader to interpret. The writer has to leave something for the reader to interpret. Otherwise, the prose is as appealing as pre-chewed food.
The writer has to think deeper about concept of beauty when writing about the girl who's as cute as a basket of kittens. OK, what made her so cute? What was the exact shade of hair? Orange highlights you say? How was it cut? Neat or messy? How about the shape of her face? Cheekbones? Large brown eyes? Anything distinctive about her breasts? Dancer's legs? Shy or aggressive?
The writer has to figure out what exactly the POV character will experience that creates in him the impression of beauty. Then select the best details to convey. Then string together the best words the reader will interpret as a depiction of beauty.
This is why Lewis characterizes this cheat as, "Please do my job for me."
5. When Lewis says, "Don’t use words too big for the subject," I hope he had in mind something like, "Superlatives are for children." When I was younger, I read Perry Rhodan novels. They were ripping yarns, but over time I noticed some inflation going on. Instead of two spaceships fighting a battle, there were two hundred ships engaging the enemy. The numbers got bigger and bigger. And if the numbers of dreadnaughts remained fixed, the size of the super-dreadnaughts they were going against were bigger and bigger. This cycle would go on for a few novels, and then they'd have to do something else.
I think Lewis' commandments are harder to keep than Heinlein's commandments. I understand them, but I find that I don't remember them. They're more tactical and mechanical, so it's harder for me to dredge up concrete examples in my own writing. They're safer because you won't get an argument like you might about Heinlein's 3rd commandment. Nevertheless, this writing process isn't something that's ever finished. We take whatever we can to improve from wherever we can.