What motivates Jonas to run away from the community with Gabriel in The Giver?
One of the great thinkers of America, Ralph Waldo Emerson, who was as popular as movie stars and musicians, wrote an essay entitled, "Self-Reliance." In this essay, he observes,
Society everywhere is in conspiracy against the manhood of every one of its members. Society is a joint-stock company in which the members agree for the better securing of his bread to each shareholder to surrender the liberty and culture of the eater. The virtue in most request is conformity self-reliance. Self-reliance is its aversion. It loves not realities and creators, but names and customs.
In the society in which Jonas lives, the members have clearly surrendered their liberty and individuality. Conformity is de rigeur; that is, it is the way of life dictated to people. Children are given certain things at certain ages, their hair is worn a certain way at particular ages, and when they are older, their way of life is chosen for them in a nameless, timeless community. However, after Jonas is chosen to become a Giver who is the storehouse of memories of the former imperfect world, he begins to realize what has been sacrificed in the lives of the citizens for their comfort and safety. For, while he now experiences pain, he also knows beauty and delight. Moreover, he is different from others, an individual with his own thoughts and feelings, not those that are shared. All superficiality has been shed from his life; Jonas feels for the first time that he is truly alive, and he is appalled at others who are
satisfied with their lives which had none of the vibrance his own was taking on.
Now that Jonas knows "reality and creators"--all that has been real in the other world with its possibility for creativity--he abhors (hates) the idea of having to live in the dull, sterile, colorless, world of conformity. Therefore, he saves Gabriel from being discarded as inferior and flees his artificial community. They hide from the search planes until they reach the real world of birds and deer and wind and snow and color and vibrant life with all its possibilities.
All of it was new to him. After a life os Sameness and predictability, he was awed by the surprises that lay beyond each curve of the road....he had never felt such simple moments of exquisite happiness.
In order to truly live, a person must experience pain and happiness; he/she must have choices and free will. Without these basic elements of life, a person is no more than a mere automaton. So, when Jonas flees with Gabriel, they choose to leave the "conspiracy of society" of which Emerson writes because they discover a world in which they can control their own destinies and they can truly live as free human beings.