Samuel Taylor Coleridge - Biographia Literaria, published 1817
In Biographia Literaria Coleridge sets out his theory of the central importance of imagination which he divides into two parts, primary and secondary.
Primary imagination is necessary to all acts of human perception. The secondary imagination is the vital poetic power, dissolving, diffusing, dissipating, "in order to recreate" or "to idealize and unify".
This imagination is the God-like faculty the poet brings to bear upon the materials of life; it is a "magical power" through which the poet expresses the ideal unity of the human soul, bringing into "balance or reconciliation" all "opposite or discordant qualities".