A partial examination only of the Imagination is to be attempted

We have hitherto been exclusively occupied with those sources of pleasure which exist in the external creation, and which in any faithful copy of it must to a certain extent exist also.

These sources of beauty, however, are not presented by any very great work of art in a form of pure transcript. They invariably receive the reflection of the mind under whose influence they have passed, and are modified or coloured by its image.

This modification is the Work of Imagination.

As, in the course of our succeeding investigation, we shall be called upon constantly to compare sources of beauty existing in nature with the images of them received by the human mind, it is very necessary for us shortly to review the conditions and limits of the Imaginative faculty, and to ascertain by what tests we may distinguish its sane, healthy, and profitable operation, from that which is erratic, diseased, and dangerous.

It is neither desirable nor possible here to examine or illustrate in full the essence of this mighty faculty.