"Spring" brings the breaking up of the ice on Walden Pond and a celebration of the rebirth of both nature and the spirit. Thoreau again presents the pond as a microcosm, remarking, "The phenomena of the year take place every day in a pond on a small scale." He revels in listening and watching for evidence of spring, and describes in great detail the "sand foliage" (patterns made by thawing sand and clay flowing down a bank of earth in the railroad cut near Walden), an early sign of spring that presages the verdant foliage to come. In its similarity to real foliage, the sand foliage demonstrates that nothing is inorganic, and that the earth is not an artifact of dead history. It is, rather, living poetry, compared with which human art and institutions are insignificant. The chapter is rich with expressions of vitality, expansion, exhilaration, and joy. Thoreau focuses on the details of nature that mark the awakening of spring. He asks what meaning chronologies, traditions, and written revelations have at such a time. Rebirth after death suggests immortality. Walden has seemingly died, and yet now, in the spring, reasserts its vigor and endurance. The narrator, too, is reinvigorated, becomes "elastic" again. A man's thoughts improve in spring, and his ability to forgive and forget the shortcomings of his fellows — to start afresh — increases. Thoreau states the need for the "tonic of wildness," noting that life would stagnate without it. He comments also on the duality of our need to explore and explain things and our simultaneous longing for the mysterious. Taking either approach, we can never have enough of nature — it is a source of strength and proof of a more lasting life beyond our limited human span. Thoreau refers to the passage of time, to the seasons "rolling on into summer," and abruptly ends the narrative. He compresses his entire second year at the pond into the half-sentence, "and the second year was similar to it." The last sentence records his departure from the pond on September 6, 1847.
In his "Conclusion," Thoreau again exhorts his reader to begin a new, higher life. He points out that we restrict ourselves and our view of the universe by accepting externally imposed limits, and urges us to make life's journey deliberately, to look inward and to make the interior voyage of discovery. Evoking the great explorers Mungo Park, Lewis and Clark, Frobisher, and Columbus, he presents inner exploration as comparable to the exploration of the North American continent. Thoreau explains that he left the woods for the same reason that he went there, and that he must move on to new endeavors. There is danger even in a new enterprise of falling into a pattern of tradition and conformity. One must move forward optimistically toward his dream, leaving some things behind and gaining awareness of others. A man will replace his former thoughts and conventional common sense with a new, broader understanding, thereby putting a solid foundation under his aspirations. Thoreau expresses unqualified confidence that man's dreams are achievable, and that his experiment at Walden successfully demonstrates this. The experience and truth to which a man attains cannot be adequately conveyed in ordinary language, must be "translated" through a more expressive, suggestive, figurative language. Thoreau entreats his readers to accept and make the most of what we are, to "mind our business," not somebody else's idea of what our business should be. He presents the parable of the artist of Kouroo, who strove for perfection and whose singleness of purpose endowed him with perennial youth. Transcending time and the decay of civilization, the artist endures, creates true art, and achieves perfection. This parable demonstrates the endurance of truth. Thoreau again urges us to face life as it is, to reject materialism, to embrace simplicity, serenely to cultivate self, and to understand the difference between the temporal and the permanent. He ends Walden with an affirmation of resurrection and immortality through the quest for higher truth. One last time, he uses the morning imagery that throughout the book signifies new beginnings and heightened perception: "Only that day dawns to which we are awake. There is more day to dawn. The sun is but a morning star."
