What is the Force? What motivates the Light AND the Dark?
"To turn from the light is to see your own shadow." -- ancient proverb.
What motivates a villain is very hard to describe, but what motivates the dark side is not so hard to understand, but it is greatly misunderstood.
Certainly power and control are motivations on the surface, they are projections of internal conflict and are later manifestations of something we all relate to, that is, to control one's own passions and emotions.
The force sensitive is born into a world with great attachment to things, to their mother most of all. The force user might find their power disturbing, they can choke those that anger them, manipulate those that resist their will. To stand in the light is to see your own shadow. The evil that can be done by the force causes anyone not a psychopath to question their own goodness.
Their attachment to things causes them to fear loss, to fear mistakes, to feel guilt for the accumulation of their failures, their impulses, their desires.
The dark side is motivated, truly motivated, by controlling these things. From there it fractures down many paths, control leads to totalitarianism, control of power allows more manipulation of others, more power over those that might hurt you, more fear that you will never be strong enough to save the ones you love even from the one thing that cannot be defeated.
Death.
The darksider, before they even realize they are being seduced by the dark side, is seeking a strong man, someone who has walked the path before, to teach them, or discipline them to control their passions, to suppress them, to repress their emotions which cause them such pain over the loss of the things they are attached to.
Luke Skywalker felt this conflict, Obi Wan admits it to Yoda when Yoda says he will not train the boy, Obi Wan asks Yoda was he any different at first?
Luke Skywalker is doubtful of his own goodness, how will he know the light from the dark? "When you are Passive, calm", Yoda replies.
The Light offers the only true answer to a Jedi, but it is an answer all confront and few can truly accept.
What did the Emperor tempt Luke with at the end? He tempted Luke with the threat of the loss of things Luke held most dear, imagine that one thing you are attached to, that one thing you cannot do with out!
Imagine a creature you hate, threatens you, that you want to destroy, threatens to destroy everything you love, but promises to spare them if you submit, if you surrender yourself to the same submission that all the darksiders seek.
Can you let go of that one thing you hold most dear? Can you really?
Can you truly let go?
This is the answer you must give to walk in the Light.
To be a Jedi is to let go of all things!
So what motivates the light? The exact same thing as the dark, to control their passions, only their answers differ.
The dark controls it with force, with power, and from there loses any control over it at all.
The light lets it go, gives it up, ceases to struggle to try and control it and only by losing everything do they gain everything and are no longer ruled by their emotions, dominated by their desires, and so they can never be ruled or dominated by others.
So then what is the Force? Is it light? Is it dark? Or both?
It is neither. It is like art, a person is a filter, and though the painting is the same intrinsic thing no matter who gazes upon it, the person takes it in, filters it from their own perspectives, and visualizes it differently.
A person takes in the force, and if they cannot accept the answer the light requires, they inevitably find themselves walking the path of the dark side.
They may not all become Sith Lords, or evil villains.
But so long as they remain attached, they are vulnerable to the seductions of those creatures.
So long as they remain attached, they have something to lose, something to fear, something to hate.
They turn from the answer the light provides, and are consumed in their own shadow until all that surrounds them is the darkness.
But I feel the movies elloquently show, that you can at any time surrender, at any time you can let go of all attachment to things, to hopes and desires, and in doing so you turn from the darkness to find it was only your own shadow blocking out all the light, you turn and face the light and in there you dwell.