From what has been said of the scale, it may easily be seen that its function is to furnish a stable basis for musical construction. It repre sents the results of ;esthetic instincts and judg ments which ha cc been accumulating for cen turies, and it is, at the same time, the embodi ment of the principle consciously or unconscious ly underlying every mansion] composition.
A second factor of psychological importance in the history of musie is the growth of polyphony and harmony (qq.v.). It has often been said that the earliest form of musical expression was melodic. It is certainly true that there are great racial as well as temporal differences in the apprehension of harmonie relations. Hottentots, e.g. have shown a keen native appreciation for European harmonies which have failed to move the Chinese and other Orientals. But, at the same time, it may be laid down as probable that the same tonal peculiarities which had led to the development of melody have led also to the prodnction of harmony, whether these peculiari ties rest, ultimately. in the fusion of simple tones (Stumpf) or depend upon clang-relation ship (Helmholtz). It must, however, be admitted that there are periods in wide]] either melody or harmony seems to have an almost independent development. The history of European music furnishes a good illustration. Western music was essentially melodic in ancient Greece. The early Christians borrowed the melodic Greek modes in mutilated form. To these was added, sery gradually, a new element. Ecclesiastical tunes were sung with the intervals of the fifth and the fourth, and attempts were made to sing different tunes together. Then came a long era of development of polyphonic music. Contra puntal arrangement reached a high degree of per fection in the service of the Church. But the
movement away from simple melody was des tined to extend much further than the perfec tion of counterpoint. Choral singing had already laid the basis for the elaborate system of har mony which now began to he formulated. By the cud of the sixteenth century the independent sig nificance of chords and their artistic connection, apart from the progression of 'voices,' came to be recognized. This was the real opening of the modern era of harmonic music. There are two chief factors which contributed to its estab lishment: ( 1 ) the Church's demand for intel ligible chorus and congregational singing, for which the complicated polyphonic forms were not suitable; and (2) the rise of the opera, which in its revival of ancient tragedy called for solo singing with harmonic accompaniment. The wealth of harmony has been greatly augmented by the development of instrumentation, whieh has readied its climax in the modern orchestra.
In making a survey of the achievements of Western music, it is important to keep in mind the fact that our system is largely a product of taste and by no means the only possible way of utilizing the tonal elements at man's disposal. Other races and other epochs have solved their musical problems in other ways. These, if not so agreeable to us as our own. have been satisfac tory to their inventors. Neither can our canons of taste be regarded as more fixed than are others. They are. on the contrary, extremely variable. Even since medireval times so radical a change has been effected in :esthetic preference as the substitution of first the fifth and the fourth. and later the major third, for the oc tatT as the most agreeable interval. What further changes will take place it is unsafe to predict.