Philosophy and Equal Temperament

It is with philosophy as with just intonation on a piano, if you get everything quite straight and on all fours in one department, in perfect tune, it is delightful so long as you keep well in the middle of the key; but as soon as you modulate you find the new key is out of tune and the more remotely you modulate the more out of tune you get. The only way is to distribute your error by equal temperament and leave common sense to make the correction in philosophy which the ear does instantaneously and involuntarily in music.