Why He Left The Civilized World
I believe that Thoreau chose the woods because the woods is a lonely place to one that is used to living in the company of other people. To truly live, in his opinion, is to be as self-sufficient as possible. I believe he chose to be alone because he was taking self-sufficiency to the utmost he could. I suppose that one could say that when living in the village, one gets so accustomed to a routine that it becomes akin to something done on autopilot, or simply by habit.
I do not believe that being alone is living life to the fullest. I believe humans are social creatures by nature, and to deprive one of those social interactions is murder on the soul. But, to each his own. I think he shied away from anything relating to village life in this experiment because it meant socializing with other people; people he believed to be beneath the ideals of his experiment, beneath his intellect, beneath the enlightened one in ten million.
Henry Thoreau needed some time to himself away from civilization because the very things that help others thrive seemed to be smothering him. He needed to focus on the facts of life. People need to sleep: He had an unfinished cabin that he slept in for quite a while. People need to eat: He had a small but sufficient garden to sustain himself. People need company: In whatever form it may come, whether it be the computer late at night, other humans, or in the case of Thoreau, simply the sounds and bustling activities of Nature herself and all of her creatures, people need the sense that there is something holding them to the life they live. I think that by retreating into the woods for this experiment, Thoeau had realized that the humans of any village in the world were not company enough in comparison to foreign and exotic Nature.