The most important idea in "Self-Reliance" is that of individualism. Emerson emphasizes that it is one's primary duty to trust one's own instincts, express oneself, and give to the world the gifts and perspective that one is unique in possessing.

Emerson supports this idea with numerous principles and examples. He says that the great men of history who are widely imitated were never themselves imitators. Moses, Plato, and Milton were not guided by tradition nor by the opinions of those around them; instead, they relied on themselves and said exactly what they thought.

One of Emerson's guiding principles in the essay is that individuals should look after their own development rather than embarking on programs of social reform. Virtue resides in the individual, and individuals should draw it out of themselves.

Emerson also warns against wanting to be—or be seen to be—consistent. He believes this desire will lead to conformity. One should refuse to be influenced by what others think and what one used to think oneself. The famous phrase "a foolish consistency is the hobgoblin of little minds" expresses Emerson's view that consistency is the enemy of development and improvement.

Finally, Emerson says that one should not pay much attention to external events but should always remain true to one's own conscience and principles.