". . . Genius or originality is, for the most part, some strong quality on the mind, answering to and bringing out some new and striking quality in nature.
Imagination is, more properly, the power of carrying on a given feeling into other situations, which must be done best according of the hold which the feeling itself has taken of the mind.
In new and unknown combinations, the impression must act by sympathy, and not by rule, but there can be no sympathy where there is no passion, no original interest. The personal interest may in some cases oppress and circumscribe the imaginative faculty, as in the instance of Rousseau: but in general the strength and consistency of the imagination will be in proportion to the strength and depth of feeling; and it is rarely that a man even of lofty genius will be able to do more than carry on his own feelings and character, or some prominent and ruling passion, into fictitious and uncommon situations. Milton has by allusion embodies a great part of his political and personal history in the chief characters and incidents of Paradise Lost. He has, no doubt, wonderfully adapted and heightened them, but the elements are the same; you trace the bias and opinions of the man in the creations of the poet.
Shakespeare (almost alone) seems to be a man of genius, raised above the definition of genius. "Born universal heir to all humanity," he was "as one, in suffering all who suffered nothing;" with a perfect sympathy with all things, yet alike indifferent to all: who did not tamper with nature or warp her to his own purposes; who "knew all qualities with a learned spirit, "instead of judging of them by his own predilections; and was rather "a pipe for the Muse's finger to play what stop she pleased," than anxious to set up any character or pretensions of his own.
His genius consisted in the faculty of transforming himself at will into whatever he chose: his originality was the power of seeing every object from the exact point of view in which others would see it. He was the Proteus of human intellect. Genius in ordinary is a more obstinate and less versatile thing. It is sufficiently exclusive and self-willed, quaint and peculiar. It does some one thing by virtue of doing nothing else: it excels in some one pursuit by being blind to all excellence but its own. It is just the reverse of the chameleon; for it does not borrow, but lends its colours to all about it: or like the glow-worm, discloses a little circle of gorgeous light in the twilight of obscurity, in the night of intellect that surrounds it.
So did Rembrandt. If ever there was a man of genius, he was one, in the proper sense of the term. He lived in and revealed to others a world of his own, and might be said to have invented a new view of nature. He did not discover things out of nature, in fiction or fairy land, or make a voyage to the moon "to descry new lands, rivers, or mountains in her spotty globe," but saw things in nature that every one had missed before him, and gave other eyes to see them with.
This is the test and triumph or originality, not to show us what has never been, and what we may therefore very easily never have dreamt of, but to point out to us what is before our eyes and under our feet, though we have had no suspicion of its existence, for want of sufficient strength of intuition, of determined grasp of mind to seize and retain it . . . ."
Excerpt from "On Genius and Common Sense"