It is not easy in words to point out how extremely large a factor in art-music is the operation of the unconscious. Instinct governed the operation of Bach and Beethoven almost as much as it does the swimming of the swan or the flying of the pigeon. For although the instinct of tonal relations is not one of those universal endowments shared by every individual to the same degree, there have appeared in the art of music a series of remarkable geniuses who seem to have had within themselves the power to turn all kinds of moods and experiences into musical expression. What part of this was due to fortunate heredity, and what to environment, and how much to original genius, pure and simple, it is impossible to say. The nature of genius always remains a mystery. At the same time, the currency which the music of these masters has gained in the world, and still maintains, goes to show that the instinct which governed them in putting together tonal forms for expressing delight, and for operating upon the feelings of the hearer, is not different in essence from that of the common listener; since experience shows that all this music affords gratification to the great majority of individuals who can be brought to listen to it a few times. Of course, it is not to be expected that a casual hearer, inattentive, it may be, and unaccustomed to remembering what he has heard, will be impressed by a long instrumental composition to the same degree as a practised hearer, and especially a hearer who has already followed the composition through several times before; but the longest symphony or sonata always contains a variety of moments which are intensely pleasing to the ordinary hearer listening seriously to them for the first time. The difference between the casual hearer and the more cultivated one is that with practice will come a perception of a larger number of these attractive moments, and finally, at last, the realization of the entire discourse as a one, having a central idea; in the same way as in a sermon a casual hearer notices here and there an idea which strikes him; then he goes off into reverie, and is only recalled by some other striking idea which attracts his attention, while the trained hearer may have followed the discourse entirely, and found it interesting from first to last.