This passage comes from the fourth section of Ralph Waldo Emerson’s major essay “Nature” (1836). This essay is one of the defining documents of the nineteenth-century American literary, intellectual, and spiritual movement known as Transcendentalism. Indeed, the quote you have selected demonstrates the essence of Transcendentalist ideas.

Transcendentalists believed that spiritual truths extend throughout all of creation, and that those truths can be grasped by an individual person’s intuition alone. That is, individuals can realize the truth simply by contemplating nature/creation, without the aid of anything else—independent of science, organized religion, etc. To put it another way that gets at the name of the movement, spiritual truth transcends creation.

With that in mind, we can turn back to the quote from “Nature.” The fourth section of “Nature” is titled “Language,” and in it, Emerson focuses on how the words we use everyday point to truth.

Let’s take the first part: “The use of natural history is to give us aid in supernatural history.” It’s perhaps surprising to say that natural history (another way of describing science) points to spiritual or super-natural ideas. But Emerson says this is absolutely clear from the language we use. He provides specific examples of words, looking at them etymologically. For instance, he says, the word “spirit” originally meant simply “wind,” and “transgression” originally meant “to cross a line” in a completely literal sense. All of the ideas we have about spiritual ideas like “spirit,” Emerson says, are rooted in our experience of the material world (phenomena like wind). Since observation of the material world is also key to science/natural history, this means that experiencing nature, no matter the reason, ultimately leads to spiritual truth.

To put it another way, this means, once again, that truth transcends the different ways we approach nature or purposes we have for observing it. The second half of the quote can now be understood to say essentially the same thing as the first half: “the use of the outer creation, to give us language for the beings and changes of the inward creation.” Experiencing and describing nature (a.k.a. “outer creation”) gives us, in a very literal sense, the words that in the end turn into the language we use to talk about the mind, soul, or spirit (a.k.a. “inward creation’).