The Well-tempered Clavichord is one of those works by which we can measure the progress of artistic culture from one generation to another. When Rochlitz met with these preludes and fugues at the beginning of the nineteenth century, only a few of them really appealed to him. He placed a tick against these, and was astonished to find how the number of these ticks increased as he played the works. If some one had told this first of Bach prophets that in another hundred years every musically-minded man would have regarded each piece in the collection as perfectly easy to comprehend, he would hardly have believed it.
The fact that the work today has become common property may console us for the other fact that an analysis of it is almost as impossible as it is to depict a wood by enumerating the trees and describing their appearance. We can only repeat again and again -- take them and play them and penetrate into this world for yourself. Aesthetic elucidation of any kind must necessarily be superficial here. What so fascinates us in the work is not the form or the build of the piece, but the world-view that is mirrored in it. It is not so much that we enjoy the Well-tempered Clavichord as that we are edified by it. Joy, sorrow, tears, lamentation, laughter -- to all these it gives voice, but in such a way that we are transported from the world of unrest to a world of peace, and see reality in a new way, as if we were sitting by a mountain lake and contemplating hills and woods and clouds in the tranquil and fathomless water.
Nowhere so well as in the Well-tempered Clavichord are we made to realize that art was Bach's religion. He does not depict natural soul-states, like Beethoven in his sonatas, no striving and struggling towards a goal, but the reality of life felt by a spirit always conscious of being superior to life, a spirit in which the most contradictory emotions, wildest grief and exuberant cheerfulness, are simply phases of a fundamental superiority of soul. It is this that gives the same transfigured air to the sorrow-laden E flat minor prelude of the First Part and the care-free, volatile prelude in G major in the Second Part. Whoever has once felt this wonderful tranquility has comprehended the mysterious spirit that has here expressed all it knew and felt of life in the secret language of tone, and will render Bach the thanks we render only to the the great souls to whom it is given to reconcile men with life and bring them peace.