By reducing imagination to the power of forming images, and by insisting that no image can be formed except out of the elements furnished by experience, I do not mean to confound imagination with memory; indeed, the frequent occurrence of great strength of memory with comparative feebleness of imagination, would suffice to warn us against such a conclusion.

Its specific character, that which marks it off from simple memory, is its tendency to selection, abstraction, and recombination.  Memory, as passive, simply recalls previous experiences of objects and emotions; from these, imagination, as an active faculty, selects the elements which vividly symbolise the objects or emotions, and either by a process of abstraction allows these to do duty for the whole, or else by a process of recombination creates new objects and new relations in which the objects stand to us or to each other (invention), and the result is an image of great vividness, which has perhaps no corresponding reality in the external world.

Minds differ in the vividness with which they recall the elements of previous experience, and mentally see the absent objects; they differ also in the aptitudes for selection, abstraction, and recombination:  the fine selective instinct of the artist, which makes him fasten upon the details which will most powerfully affect us, without any disturbance of the harmony of the general impression, does not depend solely upon the vividness of his memory and the clearness with which the objects are seen, but depends also upon very complex and peculiar conditions of sympathy which we call genius.  Hence we find one man remembering a multitude of details, with a memory so vivid that it almost amounts at times to hallucination, yet without any artistic power; and we may find men—­Blake was one—­with an imagination of unusual activity, who are nevertheless incapable, from deficient sympathy, of seizing upon those symbols which will most affect us.  Our native susceptibilities and acquired tastes determine which of the many qualities in an object shall most impress us, and be most clearly recalled.  One man remembers the combustible properties of a substance, which to another is memorable for its polarising property; to one man a stream is so much water-power, to another a rendezveus for lovers.

In the close of the last paragraph we came face to face with the great difficulty which constantly arrests speculation on these matters—­the existence of special aptitudes vaguely characterised as genius.  These are obviously incommunicable.  No recipe can be given for genius.  No man can be taught how to exercise the power of imagination.  But he can be taught how to aid it, and how to assure himself whether he is using it or not.  Having once laid hold of the Principle of Vision as a fundamental principle of Art, he can always thus far apply it, that he can assure himself whether he does or does not distinctly see the cottage he is describing, the