Because I thought it would be a fun and geeky thing to do, here are the laws of motion and friction, as applied to fiction. The cool thing is that the laws of physics totally apply–if you give them a little twist.
Every plot continues in its state of rest, or of uniform motion in a straight line, unless compelled to change that state by external forces acted upon it.
All plots begin at rest. It needs that external force to get it moving. That force is conflict. Conflict is the energy (or fuel) that powers your novel. Even in a scene between two people who get along well, there must be some conflict, possibly in the form of an outside goal or problem, or a disagreement on how to solve it.
Forces must not only move it it a straight line, but other forces must provide those intriguing twists and turns necessary to keep the story going. The reader should not be able to see the ending from the beginning.
And just as in the real world, your novel does not float in a vacuum. There is a force acting upon it that will drag it to a halt unless you apply more conflict. For that, we have the second law:
A plot will grind to a halt unless additional force is applied to it.
The time that it takes to read your novel acts as friction. Just as your car will roll to a stop when you run out of gas, your story needs fuel to keep it going. You can rely on momentum for moments of backstory, but only make it a moment here and there, like bumps in the road, in order to maintain momentum.
For that reason, you cannot have backstory in the opening pages of your novel. At that point, we don’t yet have momentum, and the backstory will just keep the story at rest and make your reader set it aside.
If you decide you do need a hill of backstory, you must provide even more conflict to get us over that hill. So make your backstory count, and make it worth the fuel.
For every plot action, there must be an equal and opposite plot reaction.
Everything you do in the story must not only have a good reason for being done, but it must have a result. If someone does something, there must be a consequence. It is OK if that consequence does not occur immediately, but it must occur. And if it does not occur immediately, give a clue that it will happen. Otherwise the reader may stop reading.
When I was reading the 2nd book in The Deed of Paksenarrion, there was a spell placed on Paks that caused her to change her goals. For the reader, it was a rather abrupt change, and I didn’t know that she had a spell placed upon her. However, there was also an intriguing encounter with the elves, and it was enough to make me suspicious. I kept reading, and many chapters later, when I had put that encounter out of my mind, it came back, with a full explanation.
Here’s a twist on that law, as applied to revisions:
For every revision, there must be an equal and complementary re-revision.
If you change something in one place, you almost certainly will have to change something else in another place. When I make a tweak, I almost never make it in one place only. It always affects something else. So if you change something, go ahead and think about what it changes elsewhere. I usually plop a bookmark in my story (in the form of a special word style that shows up in the Navigation pane), find the other thing to change it, and change it right then and there. If I don’t change both places right then, I will forget to do it later.
If it changes nothing, then the scene is probably unnecessary. Consider scrapping it.
Just for fun, can you think of any laws of science that can apply to fiction?