Emerson is best known as leader of the "transcendentalist" movement in America.
HIS LIFE AND WORKS
He was born into a prominent Boston family, one characterized by generations of service to the church (his father, William, was the minister of the venerable First Church of Boston). He attended Harvard College and Divinity School and eventually became pastor of the 2nd church of Boston--where he soon achieved recognition as an excellent preacher.
But like his father before him, he found himself being drawn into new realms of thought that challenged his orthodox Christian beliefs. The writings of the English romantics, Carlyle and Coleridge, the philosophy of Swedenborg, the new biblical text-criticism coming out of Germany, plus his own cool intellectual rather than warm pastoral nature began to distance him emotionally from his work.
Soon after his wife died in 1831, he stepped down from the ministry (1832)--to freely pursue the question of the nature and purpose of human life--and its relation to the larger natural world around man. He traveled to Europe, visiting Coleridge, Wordsworth and Carlyle in the process. When he returned to the States in 1833, he began work on his small, but revolutionary book, Nature--which he published anonymously three years later. In this book he outlined the basic ideas that underpinned his Transcendalist philosophy.
Basically he took the ancient Idealist position of Plato--in strict opposition to the mechanistic-materialist philosophy of Newton and Locke which he saw as undergirding modern life (including the Unitarian theology that was so prevalent around him). He was in part a mystic (in keeping somewhat with the older Puritan tradition!)--seeking direct knowledge of God through divine revelation, rather than through systematic theology or rational philosophy.
He felt that Newton had imprisoned the human spirit within his model of life as a machine made up of bits of matter in motion in accordance to a fixed system of natural laws. Further, he felt that Locke had only added to this error by depicting the human mind as a similar machine, linked only to the outside world through the the bombardment of external sensations upon the receptors of the mind. This mechanistic-materialistic philosophy was all lacking the force of spirit, a transcending spirit--which was to Emerson the substance that gives rise to all life, human and otherwise. To Emerson, this transcending spirit unites all life into a single harmony which flows from God--and at the same time is God.
The moral implications of Emerson's philosophy were in the vast freedoms this spirit seemed to give man--freedoms to make choices about his own life. To Emerson man was not a machine, but part of the great flow of the power of God--and capable of fulfilling the most noble visions endowed by God to the active human mind/spirit. Indeed, the human spirit was potentially so powerful that it had a proper place in the on-going unfolding of all creation. The human mind was thus not the victim of a supposedly machine-like environment around it--but was instead its natural master, inasmuch as man acted in harmony with that environment.
The Unitarians responded with denunciations--especially when he brought his ideas before the Harvard Divinty School in an address to that body in 1838.
Emerson had built up such a faith in the natural attraction of the human mind to high-minded ideas that he was a bit taken aback when his ideas failed to persuade--but only stirred animosity. He learned the hard lesson that reform of human life was not going to take place just in the presenting of ideas. There was going to have to be concerted action that accompanied these ideas. Though Emerson himself would not become an activist-reformer, many of his close associates in the Transcendalist movement would--especially those closely involved in the Abolitionist movement (to end slavery in the United States).
He spent the rest of his life serving as a lecturer, philosopher and poet--in wide demand on the lecture circuit, even being called to Harvard to present his ideas. He was definitely a man of the times, philosopher of the young, optimistic American Republic which felt that it had a mandate to show the rest of the world the higher, more humane way to live.