Explanation
The best answer to the question: What belief about life is being described in this excerpt, would be: That people who assiduously fight for their dreams, believing in them and working to build them, will eventually find them coming true.
Step-by-step explanation:
Henry David Thoreau was a man who strongly believed that humanity needed to go back to the most simple of lifestyles and that attaining dreams, when a person willingly fought hard to build them, was possible. In order to prove this, Thoreau became a living example and he decided to leave his old life behind to become almost a hermit inside a small cabin at Walden Pond. For a good while Thoreau cut himself off from his earlier lifestyle and decided to choose simplicity. From his experiences came one of his best known written works, "Walden". In this particular excerpt, from chapter 18, Thoreau is telling people that achieving dreams, when you fight assiduously for them, and without giving up, is possible and that all a person has to do, is seek to build those dreams to make them come true.