Transcendentalism was a philosophical and literary movement that flourished in New England as a reaction against 18th century rationalism, the skeptical philosophy of John Locke, and the confining religious orthodoxy of New England Calvinism.
Its beliefs were idealistic, mystical, eclectic and individualistic, shaped by the ideas of Plato, Plotinus, as well as the teachings of Confucious, the sufis, and the writers of the Upanishads and the Bhagavad Gita.
At its fundamental base was a monism holding to the unity of the world and god, and the immanence of god in the world. Because of this indwelling of divinity, everything in the world is a microcosm containing within itself all the laws and the meaning of existence. Likewise, the soul of each individual is identical with the soul of the world and latently contains all that the world contains.
Man may fulfill his diviine potentialities through rapt mystical states into which the divine is infused into the human, or through coming in contact with the truth, beauty, and goodness embodied in nature and originating in the over-soul.
Thus occurs the correspondence between the tangible world and the human mind and the identity of moral and physical laws through the belief in the divine authority of the soul's intuitions and impulses.
Based on the identification of the individual soul with god, there developed the doctrine of self-reliance and individualism, the disregard of external authority, tradition and logical demonstration and the absolute optimism of the movement.
For more info read:Thoreau, Emerson, A.M. Alcott, Goethe, Richter, Novalis, Coleridge, Carlyle, Wordsworth and Dickinson.