"Matter + Cohesion + Energy + Gravity trying to restore equilibrium = Ripples." via Twitter @_Astro_Nerd_
She’s talking physics, but I’m seeing the same concept applied to writing fiction.
The undisturbed surface of a pond is at equilibrium, like a blank sheet of paper.
Add characters (matter) cohesion (what draws them together) energy (what the characters are doing) and gravity (the circumstances pulling them apart) and you get increasing/decreasing tension in waves, like ripples. You can move the variables around using mathematical principles to keep the story in balance.
I’m going to need to think about this a bit, but it makes more sense to me than a lot of "how to write" book advice.