Thoreau expressed a clear vision of the unity of man, nature, and heaven. Following a description of moth cocoons resembling leaves suspended over the edge of the meadow and the river, he wrote in his journal entry for February 19, 1854:
. . . it is startling to think that the inference has in this case been drawn by some mind that, as most other plants retain some leaves, the walker will suspect these also to. Each and all such disguises . . . remind us that not some poor worm's instinct merely, as we call it, but the mind of the universe rather, which we share, has been intended upon each particular object. All the wit in the world was brought to bear on each case to secure its end. It was long ago, in a full senate of all intellects, determined how cocoons had best be suspended, — kindred mind with mine that admires and approves decided it so.
This leap from the particular to the universal, from the mundane to the divine, is found throughout Thoreau's work.
Nature — its meaning and value — comprises one of the most pervasive themes in Thoreau's writings, expressed through both painstaking detail and broad generalization. Like Emerson, Thoreau saw an intimate and specific familiarity with the reality of nature as vital to understanding higher truth. Thoreau's Transcendental quest toward the universal drew him to immerse himself in nature at Walden Pond from 1845 to 1847. It led him to observe the natural world closely in order ultimately to "look through and beyond" nature, as he wrote in his journal on March 23, 1853. Thoreau's attraction to nature went far beyond emotional appreciation of its beauty; he embraced its harshness as well. Nature was, as he wrote in his essay "Walking," "a personality so vast and universal that we have never seen one of her features." There could be no "great awakening light" of understanding without knowledge of the manifestations of the universal in the observable world.
Thoreau was aware, however, that there was a fine line between inspiration through concrete knowledge of nature and fruitless preoccupation with masses of scientific detail. He saw that there was a danger of becoming "dissipated by so many observations" (journal entry, March 23, 1853), and recognized his own tendency to lose sight of the ultimate goal of higher understanding. On August 19, 1851, Thoreau wrote in his journal:
I fear that the character of my knowledge is from year to year becoming more distinct and scientific; that, in exchange for views as wide as heaven's cope, I am being narrowed down to the field of the microscope. I see details, not wholes nor the shadow of the whole.
