New England Transcendentalism developed in part out of American Unitarianism, which was well established by 1825. It drew, in particular, upon the "liberal Christianity" of Dr. William Ellery Channing. Unitarianism spread from Massachusetts throughout New England, from church to church, primarily as dissatisfied members of Congregational parishes separated from conservative, Calvinistic parent churches. American Unitarianism had British and European antecedents traceable back to the Reformation.
Dr. Channing — described by Emerson in his "Historic Notes of Life and Letters in New England" as "one of those men who vindicate the power of the American race to produce greatness" — was the recognized leader of American Unitarianism. He proclaimed the major beliefs of the faith in 1819 in "Unitarian Christianity," a sermon delivered in Baltimore at the ordination of Jared Sparks. In 1820, Channing organized the Berry Street Conference, out of which the American Unitarian Association was established in 1825. In formulating his liberal Christianity, Channing looked to the Scriptures and to his own understanding, not to dogma handed down by preceding generations.
.Strictly speaking, the term Unitarian refers to the belief that God is one being instead of the Trinity of Father, Son, and Holy Spirit. (The Congregational parishes from which Unitarian churches broke off in the nineteenth century were Trinitarian.) New England Unitarianism, however, represented more than a rejection of the doctrine of the Trinity. It encompassed a range of liberal ideas. The Unitarians believed in God's goodness and loving kindness, in man's likeness to and ability to comprehend God, and in the human capacity for spiritual, moral, and intellectual improvement. In his "Unitarian Christianity," Channing had declared, "The idea of God, sublime . . . as it is, is the idea of our own spiritual nature, purified and enlarged to infinity. In ourselves are the elements of the Divinity." Self-culture was the means of understanding God and of bringing the individual closer to God's perfection. This idea contrasted sharply with the Calvinistic concept of innate depravity. The Unitarians also denied the notion of predestination, accepting instead free will and personal responsibility. They believed simultaneously and inconsistently in the rationality of faith and in revelation as presented in the Bible, particularly in the New Testament miracles. They reconciled this inconsistency by asserting that rationality itself was a form of revelation.
