Walden has an earnest, optimistic mood that encourages the reader to see the potential in Thoreau's ideas. In "Economy" he acknowledges the challenge of getting people to accept a simpler way of life, but he embarks on his project with enthusiasm:
All change is a miracle to contemplate; but it is a miracle which is taking place every instant. Confucius said, “To know that we know what we know, and that we do not know what we do not know, that is true knowledge.” When one man has reduced a fact of the imagination to be a fact to his understanding, I foresee that all men will at length establish their lives on that basis.
The idea of a "miracle [...] taking place every instant" seems unlikely, but Thoreau insists that through just such a process, people will transition back to an agrarian way of life. Phrases like "all change is a miracle to contemplate" reveal his sense of wonderment and hope. Later, the mood takes a slight downturn; at the beginning of "The Pond in Winter," Thoreau awakens in a state of anxiety, filled with vague questions like "how–when–where." However, the initially-anxious mood quickly resolves into one of tranquility, determination, and optimism as he realizes that Nature has "no question on her lips." For the remainder of that section, he uses work to focus his mind and divests himself of worry.
Another interesting aspect of this work is the relationship between moods and seasons. Walden is structured around the cycle of the seasons; it begins in the spring as the author prepares to build his house, and it ends with the return of spring as he reflects on his experiment. This cyclical structure creates a sense of hope, renewal, and optimism that resolves the anxiety of "The Pond in Winter." Overall, Walden tends toward a mood of earnestness, optimism, and hope for the betterment of humanity. Brief moments of doubt lend a believable human aspect but never overshadow the positive mood.