It is a well-established fact that our approach to music is generally twofold: this is the physicists' as well as the musicians' doing. One the one hand, music is considered to be based on acoustics, or even mathematics, which ought to give it the status of a science; on the other hand , it is acknowledged that it proceeds from psychological and sociological phenomena which, over the ages, have developed into an art, itself depending on various crafts. There is no longer any contradiction between the two approaches so long as one is prepared to accept them jointly, with enough insight to respect the methods proper to each end of the "chain."