The Transcendentalist movement occurred from the latter end of the 18th to the beginning and middle of the 19th century. It was characterized by moving away from the heretofore accepted ideas of religion and society, and focused on the idea that mankind can and must "transcend," and discover the meaning of life based on the merits of individual intuition rather than canonical dictations. This movement, as with many others, does not only refer to poetry, but to many topics- literature, philosophy, religion, etc.
The movement is said to be based on principles found in the writings of philosopher Immanuel Kant.
Nature was of extreme importance to transcendentalists, who desired to strip away the excesses of the world and get back to the simple truths of life. Those who worked with the land- farmers and foresters- were thought to be the best of men, and not to have lost sight of true worth (as opposed to city dwellers, who are cut off from nature). This very idea, supposedly, is what induced Thoreau to hole up in the cabin beside Walden Pond to write his famous book.
Though nature was the goal of the physical world, transcendentalists also placed great importance on intelligence. Roughness of body should not induce roughness of mind, but rather lift it out of its constraints by putting it in contact with the great power of nature. Philosophy was to be cultivated, along with general knowledge.
The transcendentalists wished to separate the ideas of of 'religion' and 'spirituality.' They saw religion as being an institution, almost like a government, with laws and constraints. They cherished their own spirituality, which they saw best as a connection to nature, and with the living spirits or life force within all natural things. This is not to say that they were anti-religion, or atheists. However, they felt that there was more to be cultivated, spiritually speaking, than could be done through the church and religious community (namely: internally).
Let's take a look at the poems of some famous Transcendentalists.
Walt Whitman: "When I Heard the Learn'd Astronomer"
Whitman's transcendentalist enthusiasm abounds in this poem. It begins with the image of an astronomer, and all his technical information: "proofs and figures," "charts and diagrams", etc. The astronomer is received in a grand hall, "with much applause", and begins his lecture. However, the speaker of the poem is not impressed, and feels rather oppressed in this unnatural atmosphere. Finally it becomes too much and the listener, "rising and gliding out" goes outside into the darkness and into "the mystical moist night-air" where he "look'd up in solemn silence at the stars." It is only outside, surrounded by nature, away from the trappings and posings of society, that the speaker makes a real connection with the stars, which are the astronomer's subjects. The stars and the outdoors represent nature, with its internal wisdom and knowledge, while the astronomer and audience indoors represent the repression (of society, of modernity) that disconnects mankind from its true roots and, therefore, from important self-knowledge.
Ralph Waldo Emerson: "The River"
One of several of his poems treating on the subject of the Concord River, Emerson's "The River" reveals his transcendentalist leanings. Returning to the river bank that he loved as a child, the speaker feels a strong connection between himself and his natural surroundings. "These are the same" he says of the rocks, trees and flowing water, "but I am not the same, / but wiser than I was." Next comes the anthropomorphization (humanization, essentially) of these very same surroundings. "Call not Nature dumb," the speaker exhorts ("dumb" in this case meaning mute or silent), "These trees and stones are audible to me." The natural surroundings have a special language to which the speaker feels in tune- "faery syllables." Everything- stones, trees, water, wind and flowers- all have a voice. Though the speaker is not an essential part of this scene, not of the same "race" as the natural things, there is no enmity between them, but rather sympathy and paternal love. The landscape welcomes the speaker back, as a family would welcome a returning son. Thus Emerson reveals his transcendentalist tendencies, giving nature emotions that are sympathetic to those of man.
Other famous Transcendentalist poets include: Henry David Thoreau, Emily Dickinson, and Margaret Fuller.