Emerson uses the following metaphor to illustrate the transcendence he feels in nature:
In the woods, [...] I become a transparent eye-ball; I am nothing. I see all.
As he becomes this "transparent" eyeball, Emerson is filled with a spiritual feeling of not being a mere individual, saying that "all mean egotism vanishes." In such a state, he is able to simply experience the world without judgment instead of worrying about his commonplace life.
The word “transparent” in this context suggests that someone who is in this state is empty. Emerson, throughout this essay and his intellectual career, bemoans the damage that dogma and tradition have wrought upon people. Individuals who have been taught to revere traditional sources of knowledge—like church, government, and culture—will defer to those sources for understanding rather than looking to their own experiences. Being "transparent," on the other hand, means emptying oneself of these external attachments, allowing oneself to perceive the world without the burden of others' thoughts.
This seeing without prejudice elevates man to a state of divinity. Emerson thinks that, in nature, when one loses oneself, they gain the ability to feel divine energy flowing through them and become a part of God. What Emerson describes as the ability to "see all" is a form of omniscience. Omniscience, in Christian theology, is a property of God. Emerson uses the language of omniscience to convey how he feels divine, transcendent, and enlightened in nature.
Emerson, throughout Nature, acknowledges that human subjectivity affects one's view of nature. He points out that a beautiful landscape can appear somber to one who just experienced loss and that an already majestic landscape can become even more majestic if one is in a joyful mood.
Since perception has the ability to change the entire mood of a landscape, later in the essay, Emerson calls eyes (all eyes, not just the transparent eyeball) "the best of artists." How one sees the world changes how one thinks about it. The self is like the eye because both the internal state of a person and the physics of optics affect the judgments of one's mind. For example, a happy person might look out at a sunset and think about its pure beauty, while a sad person might look out at a sunset and think about the nature of the dying day.
Emerson, unlike other philosophers, does not bemoan that the subjectivity of eyes or emotional states is a barrier to knowledge. In fact, he often praises the human ability to see one's own mood reflected in nature, since this reflection allows nature to show people parts of themselves from another perspective. To that end, Emerson praises the eye as an artist because a difference of perception has the ability to make the world more beautiful.
However, there is a suggestion in this metaphor that, in order to be a transparent eye, one has to give up a little bit of that subjectivity. One must give up their internal prejudices and tendency to project their own feelings onto the world to get the complete transcendent feeling of divinity. The ability to see oneself in nature is human, but the ability to see all as a transparent eyeball is divine.
Emerson metaphorically categorizes each time of day as a kingdom in order to emphasize their unique virtues:
The dawn is my Assyria; the sun-set and moon-rise my Paphos, and unimaginable realms of faerie, broad noon shall be my England of the senses and the understanding; the night shall be my Germany of mystic philosophy and dreams.
The language shows that all aspects of nature are beautiful and interconnected. All are compared to gorgeous and mighty places.
Emerson compares the dawn to Assyria, which was an ancient Mesopotamian kingdom known for its splendor and strength. He makes this comparison in order to emphasize the glorious appearance of the sunrise.
Paphos—Emerson’s sunset—is a town in Cyprus that is associated with the Greek Goddess of love and beauty, Aphrodite. By invoking such a metaphor, Emerson continues his trend of using classical beauty as an image to elevate nature. Particularly, by using Paphos as a reference, he shows that nature has a divine beauty to it.
Broad noon is categorized as "England of the senses and the understanding," likely because the light, since it is the brightest, is best for clearly seeing natural phenomena. England was associated with Empiricism, that is, the philosophical school that believed observation and sense perception are key to scientific understanding.
Emerson casting the night in the role of Germany and saying that it is full of "philosophy and dreams" demonstrates that night is a time for creation. Everything looks different in the darkness, and to Emerson, that inspires thought. He chose to compare the night to Germany because much of the philosophy that inspired Emerson was German. He particularly was interested in Idealists like Immanuel Kant and Romanticists like Friedrich Schleiermacher.
Emerson invokes several common metaphors involving nature to substantiate his theory that nature teaches us conceptual language:
An enraged man is a lion, a cunning man is a fox, a firm man is a rock, a learned man is a torch. A lamb is innocence; a snake is subtle spite; flowers express to us the delicate affections. Light and darkness are our familiar expression for knowledge and ignorance; and heat for love. Visible distance behind and before us, is respectively our image of memory and hope.
Emerson, through using these examples, roots his readers' understanding of lofty concepts (like innocence and knowledge) in physical facts of the natural world. He therefore shows that the phenomena in the natural world are not shallow, for every natural fact gives rise to abstract ideas. In turn, someone can understand abstract ideas better by looking at the natural fact that is equivalent to them. In other words, we can understand ourselves better by looking at the natural world.
For example, in the paragraph after the metaphor, Emerson points out that many people come to realize the interconnectedness of the world by looking at the ripples upon a stream. Seeing how one small stone can create large disturbances on the water’s surface reveals how interconnected the world is. One small stone can set off a ripple that sends rings out to the far edges of the stream. Emerson thinks that anyone looking at such a phenomenon will be inclined to think about the interconnectedness of all things and the universal soul, while the river itself leads to thoughts of time passing. In turn, Emerson's use of metaphor helps readers grasp some of the essay's more abstract concepts.
In the following metaphor, Emerson compares pith (the spinal tissue or the central material in the stem of a plant) and bone marrow to the moral law in order to convey how central ethics are to life and existence:
The moral law lies at the center of nature and radiates to the circumference. It is the pith and marrow of every substance, every relation, and every process.
Emerson writes that nature has four purposes: commodity, beauty, language, and discipline. These four things are what nature is meant to supply to humanity—a commodity is to be used, beauty is to be perceived, language is to be learned, and discipline is to be studied. But, even though those are the uses, or “ends” of nature, Emerson needs to establish what properties allow nature to be used for these ends. So he turns to the concept of the moral law.
At the center of all nature, Emerson argues, is the moral law. The moral law is the way to live ethically. It contains all correct dictates about right and wrong. Those who believe in the moral law consider it to be objective, and many religious people believe that moral law is equivalent to God’s will.
Calling it the "pith" or "marrow" of nature leads one to understand that themoral law is an essential part of nature. Therefore, all properties of nature contain within them the moral law. The moral law is not something that can be taken out of nature and confined in the minds of humans. Emerson points out that different men who are exposed to different landscapes have similar moral conclusions, and he takes this as evidence that the same moral law exists in all natural surroundings.
Compare this quotation from an Idealist philosopher Emerson was inspired by, Immanuel Kant: "Two things fill the mind with ever new and increasing admiration and awe, the more often and steadily we reflect upon them: the starry heavens above me and the moral law within me." Emerson would push back against this quotation because, for him, there is moral law within the starry sky, existing there just as much as it exists within the individual.