Development of the Existence
From lifelessness came life, from dead matter came spirit. With life came perception: the perception of beauty and ugliness, serenity and fear. The Force grew strong as life grew stronger. Life is the universe's way of perceiving itself, the Force is the strength of its perception. As life grew, evolved, became more sophisticated, there came intelligence - and with it, the capacity of understanding. Intelligent beings questioned the universe, and when they were clever enough to ask the questions in the right way, the universe answered. The Force became stronger, more sophisticated, as intelligence spread and sapient's knowledge of the universe deepened.
Yet the nature of the Force is hidden and subtle. Questions about the nature of matter and energy are more easily answered. Intelligent beings developed a high technology by understanding of physical law - yet understanding of the universe's mystical nature lagging behind. Intelligent beings built advanced cultures which were cold, cruel, ignorant of the beat of reality's heart.
So stood the galaxy, until the rise of the Jedi. They studied the Force, they took first few steps on the road to universal harmony. As their mastery deepened, as their fame spread, and as their works began to bring harmony and freedom to the galaxy, they were betrayed. For the Force is not itself good or evil, it is a reflection of nature, and nature itself can be cold and cruel. Evil ones can harness the force to their will - and, by doing so, lose something of their humanity, becoming virtual avatars of the Dark Side of the Force. For the Master of the Dark Side, as for a Master of the Light, it cannot be said whether one controls the Force, or the Force the Master, to ask which is the actor and which the acted upon is a question of no meaning. It was inevitable that some would use the Force to slake their base lust for wealth and power. The Dark Side is easy and seductive, the first successes brought thirst for more. These evil ones brought the great Jedi low, hunting down and killing all of their ancient order. All - or almost all.
...Jedi Master Yoda and Jedi Mitth'raw'nurida