The Transcendentalists emerged from a small group of New England intellectuals in the first half of the nineteenth century. Influenced by European Romantics, they argued that there were certain truths that transcended logic, and that could best be understood through intuition rather than rational thought. They rejected, in short, the Enlightenment focus on reason, observation, and calculation. They were especially critical of the form of Unitarianism espoused by William Ellery Channing, which Emerson derided as "corpse-cold."
Transcendentalists also celebrated the individual, pointing out that God had created man in his own image, and endowed him with an intellect and spirit that was divine.For transcendentalists, especially Emerson, people, and indeed everything on Earth, was inseperable from God. For Emerson, in particular, this led to a radical celebration of the individual. Other transcendentalists, notably Henry David Thoreau, took this individualism into the sphere of social action, criticizing many of the social ills of his day, especially slavery and what Thoreau perceived as the acquisitiveness and shallowness of modern society.
Transcendentalism can thus be understood as not only a reaction to the rigidly rational traditions of the Enlightenment and the conventions of European philosophy and art, but also as a protest against early nineteenth century society, rapidly changing in the face of the Market Revolution, Manifest Destiny, the Second Great Awakening, and the expansion of slavery.