The poet is not content with this description. The swiftness and silentness of those passing hours remind him of the flight of birds along the sky. The resemblance strikes him as beautiful. He embodies it in his description. It is an ideal conception. He goes further. He sees in the water, not the reflection merely of the stars, but the stars themselves, as many in the sea as in the sky. Here is a departure from the truth, from the actual, an advance into the region of the ideal. Imagination, thus set free, takes still further liberties: attributes to the inanimate wave the _dimpled cheek_ of beauty, ascribes its restlessness not to the laws of gravitation, but to the force of a strictly human passion, under the influence of which it leaps into the air toward the object of its affection, seizes it, and holds it, trembling, in its embrace. § XI.--HISTORICAL SKETCH. VARIOUS DEFINITIONS, AND THEORIES OF IMAGINATION BY DIFFERENT WRITERS. _Definition of Dr. Reid._--_Reid_ makes it nearly synonymous with simple apprehension. "I take imagination, in its most proper sense, to signify a lively conception of _objects of sight_," the conception of things as they appear to the eye. _Addison_ employs the term with the same limitation, that is, as confined to objects of sight. _Of Stewart._--_Stewart_ regards this as incorrect, holds that imagination is not confined to _visible_ or even _sensible_ objects. He regards it as a complex, not a simple power, including simple apprehension, abstraction, judgment, or taste, and association of ideas; its province being to select, from different objects, a variety of qualities and circumstances, and combine and arrange them so as to form a new creation of its own. _Of Brown._--_Brown_ differs not essentially from the view of Stewart. He also makes imagination a complex operation, involving conception, abstraction, judgment, association. He distinguishes between the _spontaneous_ and the _voluntary_ operation of the imaginative power; in the former case, there is no voluntary effort of selection, combination, etc., but images arise independently of any desire or choice of ours, by the laws of suggestion; and this he holds to be the most frequent operation of the faculty. In the case of voluntary imagination, which is attended with desire, this desire is the prominent thing, and serves to keep the conception of the subject before the mind, in consequence of which, a variety of associated conceptions follow, by the laws of suggestion, in regular train. Of these suggested conceptions and images, some, we approve, others, we do not; the former, by virtue of our approval, become more lively and permanent, while the latter pass away. Thus, without any direct effort or power of the will to combine and separate these various conceptions, they shape themselves according to our approval and desire, in obedience to the ordinary laws of suggestion.