By claiming that people can come to know nature "by degrees," Emerson now distinguishes which faculties people use in this process. He names these faculties Understanding and Reason, and he attempts to show the relationship between them.
Everything in nature offers lessons that we can learn. Understanding requires our perceiving how natural objects differ from — and resemble — each other. Included as natural objects are Debt and Property, which today would be distinguished as social or economic issues. Emerson suggests that an understanding of Debt and Property is needed most by those who suffer from them, in part because they both teach discipline to people. However, readers might consider Emerson's comments harsh and uncaring, especially given the inflated tone of his language, which bears quoting: "Debt, grinding debt, whose iron face the widow, the orphan, and the sons of genius fear and hate; — debt, which consumes so much time, which so cripples and disheartens a great spirit with cares that seem so base, is a preceptor whose lessens cannot be foregone." He holds Debt and Property equally valid for offering lessons and instruction in life.
Singling out the role of the Will for particular consideration, Emerson argues that exercising the Will teaches the meaning of power — power that we can use to dominate nature and make it a reflection of ourselves. Note that he continually argues for nature's being made to serve us — "It is made to serve" — an idea that is startling, given the generally accepted opinion that Emerson's key ideas include our metaphysically becoming one with nature, and nature's supremely ruling over us. But here he says that we shape nature, and that our wills can mold it into what is useful.
If Understanding is concerned with the knowledge of how objects function in the world, then Reason, the second major point under the heading of Discipline, is the intuition needed to understand those objects. Emerson's definition of Reason is markedly different than ours today. For us, Reason means the process by which we logically and rationally deduce different phenomena; for him, however, Reason is tied to intuiting how nature, which he believes is a moral teacher, offers ethical and spiritual insights. Reason is linked to intuition, Understanding to rationality. Every natural object offers a sermon on some spiritual or divine reality. For example, the fisherman learns firmness, which is morally good, from observing centuries-old, sea-beaten rocks: To be firm about something is a morally correct way of acting and shows to what extent a person will defend what he or she thinks is right.
Emerson then returns to the theme that all things in nature create a single whole. Analogies and resemblances between physical and spiritual realities cause the mind to perceive the universe as a single, organic whole, with each part significant and harmonious. This unity also encompasses relationships between people, whose bodies Emerson regards as nature's most perfect products and the objects that most eloquently embody spiritual truths.
Also important in this section is Emerson's tying together many of the other themes found throughout the essay. For example, the unity of all objects in nature is the single most important ordering mechanism defining our lives. To express this ordering, Emerson likens his belief that every universal truth recalls all other truths to the geometrical shape of a circle, which has no beginning, no end: "It is like a great circle on a sphere, comprising all possible circles; which, however, may be drawn, and comprise it, in like manner." The circle best represents nature's order because all circles have the same form, just as all of nature's truths recall one another.