In these and other ways the principles of musical effect afford touchstones for the detection of prevalent but erroneous views--views which contain their element of truth, but are still fallacious because partial. But the same principles are also capable of yielding more positive and detailed insight into the nature of musical appreciation. They illuminate, for example, that perplexing problem of expression--why it is that from the same piece of music one person gets so much more than another. The fact is familiar to every one. Every one knows that of two persons equally sensitive to music on the sensuous and formal side, of good «ear,» and familiar with the effects of harmony, melody and rhythm, one will get far deeper meanings, will be far more elated and inspired, than the other. How can this be? Our theory of expression gives the clew. We have seen that bodily states set up by imitation are the basis of musical emotions. Hearing is always a sort of ideal performing. In listening to a melody we always feebly contract our throat muscles as if to sing, and the perception of rhythm is always accompanied by an incipient «keeping time.» These bodily acts, however faintly realized, set up their appropriate feelings, the feelings we associate with their actual performance. But now it should be noted that the richness, quality, and significance of these feelings will depend in the case of each man on his particular associations--that is to say, on his entire personal character. Evoked by similar bodily states, the mental emotions will be always as dissimilar as the men who feel them. «We cannot conceive,» says Thoreau, «of a greater difference than that between the life of one man and that of another.» He might truly have added that we cannot conceive of a greater difference than that between the feelings of one man and those of another in hearing the same piece of music, which excites in both the same tremors and thrills, but vistas of thought how utterly unlike! Musical appreciation is thus subject to the same variations which make the ordinary experiences of men so diverse. The prophet on fire with righteous indignation and the common scold undergo in anger the same suffusion of blood, the same boiling up of the organs; yet how different in dignity and value are their sentiments! And music, by setting up a certain sympathetic turmoil in the organs, will plunge one man into a selfish opium-dream and will fill another with the rarest, most magnanimous aspirations. It follows as a practical corollary that he who would get from music the best it has to offer must cultivate the best in himself. No fine sensibility in him, no large heroism, no generosity or dignity or profundity of character will be without its quiet, far-reaching effect on his appreciation of music.