Imagination is the basic and most important creative faculty in a poet. No poet can write poetry without the faculty of imagination. Imagination is the faculty by which a poet observes different forms and objects in human life and nature, and unifies them into one whole which is more beautiful and more sublime than the original ones. With its "plastic stress" it dissolves and diffuses different objects in to one 'Sweet Solution'. Therefore imagination is called 'shaping and unifying power.'
Coleridge divides imagination into two forms or stages:
(a)the Primary, and,
The primary form of imagination is natural and involuntary. It uses only one sense-the sense of perception-and observes the tangible forms of persons, places, things and subjects of nature. Then this primary imagination fuses them into one whole, but only in the tangible form.
The more important form of imagination is the secondary form. It is a conscious form of imagination. It is a composite faculty of the soul, using all faculties; perception, intellect, will, emotions and spirituality. As such, it is more active and more comprehensive faculty than the primary imagination. In its 'shaping and modifying' process the mind and nature act and react on each other. The mind acting on nature becomes one with nature; and nature acting on the mind become one with the mind. Thus mind and nature get identified. Thus, the primary and secondary forms of imagination have the same faculty of 're-creation' with a difference of only 'degrees' or 'range of comprehension' and not in essentials.