Imagination is not the exclusive appanage of artists, but belongs in varying degrees to all men.  It is simply the power of forming images.  Supplying the energy of Sense where Sense cannot reach, it brings into distinctness the facts, obscure or occult, which are grouped round an object or an idea, but which are not actually present to Sense.  Thus, at the aspect of a windmill, the mind forms images of many characteristic facts relating to it; and the kind of images will depend very much on the general disposition, or particular mood, of the mind affected by the object:  the painter, the poet, and the moralist will have different images suggested by the presence of the windmill or its symbol.  There are indeed sluggish minds so incapable of self-evolved activity, and so dependent on the immediate suggestions of Sense, as to be almost destitute of the power of forming distinct images beyond the immediate circle of sensuous associations; and these are rightly named unimaginative minds; but in all minds of energetic activity, groups and clusters of images, many of them representing remote relations, spontaneously present themselves in conjunction with objects or their symbols.  It should, however, be borne in mind that Imagination can only recall what Sense has previously impressed.  No man imagines any detail of which he has not previously had direct or indirect experience.  Objects as fictitious as mermaids and hippogriffs are made up from the gatherings of Sense.

“Made up from the gatherings of Sense” is a phrase which may seem to imply some peculiar plastic power such as is claimed exclusively for artists:  a power not of simple recollection, but of recollection and recombination.  Yet this power belongs also to philosophers.  To combine the half of a woman with the half of a fish,—­to imagine the union as an existing organism,—­is not really a different process from that of combining the experience of a chemical action with an electric action, and seeing that the two are one existing fact.  When the poet hears the storm-cloud muttering, and sees the moonlight sleeping on the bank, he transfers his experience of human phenomena to the cloud and the moonlight:  he personifies, draws Nature within the circle of emotion, and is called a poet.  When the philosopher sees electricity in the storm-cloud, and sees the sunlight stimulating vegetable growth, he transfers his experience of physical phenomena to these objects, and draws within the circle of Law phenomena which hitherto have been unclassified.  Obviously the imagination has been as active in the one case as in the other; the differentia lying in the purposes of the two, and in the general constltution of the two minds.

It has been noted that there is less strain on the imagination of the poet; but even his greater freedom is not altogether disengaged from the necessity of verification; his images must have at least subjective truth; if they do not accurately correspond with objective realities, they must correspond with our sense of congruity.  No poet is allowed the licence of creating images inconsistent with our conceptions.  If he said the moonlight burnt the bank, we should reject the image as untrue, inconsistent with our conceptions of moonlight; whereas the gentle repose of the moonlight on the bank readily associates itself with images of sleep.