Susanne Langer says

Art is the articulation, not the stimulation or catharsis, of feeling; and the height of technique is simply the highest power of this sensuous revelation and wordless abstraction.

The arts, like language, abstract from experience certain aspects for our contemplation. But such abstractions are not concepts that have names…. Artistic expression abstracts aspects of the life of feeling which have no names, which have to be presented to sense and intuition rather than to a word-bound, note-taking consciousness.

When we say that a work has a definite feeling about it, we do not mean that it either symptomizes this feeling, as weeping symptomizes an emotional disturbance in the weeper, nor that it stimulates us to feel a certain way. What we mean is that it presents a feeling for our contemplation… Nothing is so elusive as an unsymbolized conception. It pulsates and vanishes like the very faint stars, and inspires rather than fixes expression.

Whenever a feeling is conveyed by such an indirect rendering, it marks a height of artistic expression. Among the forthright and familiar conventions of imitation, a sensuous transformation acts much as a strong metaphor does among the well-understood conventions of literal speech: its feeling is more poignant and its meaning more impressive than the import of ordinary communication. It conveys a summation and an essence. Why?

For the same reason that a metaphor is apt to be more revealing than a literal statement… In the history of language, in the growth of human understanding, the principle of metaphorical expression plays a vastly greater role than most people realize. For it is the natural instrument of our greatest mental achievement -- abstract thinking.

Every work of art expresses, more or less purely, more or less subtly, not feelings and emotions which the artist has, but feelings and emotions which the artist knows; his insight into the nature of sentience, his pictures of vital experience, physical and emotive and fantastic.

Such knowledge is not expressible in ordinary discourse. The reason for this ineffability is not that the ideas to be expressed are too high, too spiritual, or too anything-else, but that the forms of feeling and the forms of discursive expression are logically incommensurate, so that any exact concepts of feeling and emotion cannot be projected into the logical form of literal language. Verbal statement, which is our normal and most reliable means of communication, is almost useless for conveying knowledge about the precise character of the affective life. Crude designations like “joy,” “sorrow,” “fear,” tell us as little about vital experience as general words like “thing,” “being,” or “place,” tell us about the world of our perceptions.

As soon as human conception finds an adequate symbol, it grows like Jack’s beanstalk, and outgrows the highest reaches of what seemed such an adequate form of expression. The better the symbolism, the faster it has to grow, to keep up with the thought it serves and fosters. That is clearly demonstrated by language. A child with ten words to its credit has certainly more than ten concepts at its command, because every word lends itself at once to generalization, transfer of meaning, suggestion of related ideas, all sorts of subtle shades and variations created in use. The same thing holds for artistic expression. Just as language grows in subtlety, in syntactical forms and idioms as well as in vocabulary, so the power of articulation through sensuous form grows with the needs of the conceiving mind.