The mental power of image-making is one thing, or aspect; and it should appropriately be called Imagination. The perception of the image, the grasp of its implications, and the control, which are necessary to a successful expression, may vary in vividness and strength: but this is a difference of degree in Imagination, not a difference in kind. The achievement of the expression, which gives (or seems to give) “the inner consistency of reality,” is indeed another thing, or aspect, needing another name: Art, the operative link between Imagination and the final result, Sub-creation.

      — J.R.R. Tolkien, On Fairy-Stories


Subcreation.net