For some ten centuries the European tradition has been particularly distinguished from other music cultures by the phenomenon of simultaneity. The eighteenth century in particular saw the erection of a magnificent edifice in which harmony undisputedly ruled over all other musical elements. The great romantics wielded harmony as an expressive means of the very finest sort. Even theoreticians were content, for here lay an open field allowing systematic excavation. Music could now be ‘explained’, and functions and cadences, modulations and alterations obediently joined ranks in a well-ordered and logical whole. Ever since, generations of musicians have been and indeed continue to be trained in what we call ‘the theory of harmony’. While new discoveries in this field would hardly seem likely, the reverse side of the medal is twofold:

• 1. The theory of harmony as it is understood today covers only a few centuries of the entire development of ‘simultaneity’ in the broad sense of the word;

• 2. Even more fatal to unimpeded rhythmic and/or melodic development than this restriction is the fact that simultaneity plays such a primary role in our experience. Here, music reacts like any other living organism: one-sided development of a single aspect can work to the detriment of other ones.

Only now are we able to view these matters more clearly. A deeper study of some Eastern cultures has made us aware of our inferiority in terms of melody and rhythm. But these are indeed cultures in which simultaneity is of only secondary significance! While it cannot be ruled out that we Westerners have a natural disposition for harmony, it is at the same time true that thoughtful musical training can protect us from one-sidedness and atrophy.

Once there was a time when we took care with our dosage of dissonances, and now we do likewise with our consonances. However the case may be, as long as we remain oversensitive to such phenomena, simultaneity will continue to form one of the main problems of Western music.

What did the twentieth century achieve in this field? By now we realise that there is no simple answer to this question, having experienced every aspect ranging from uncompromising counterpoint (Hindemith in the 1920s), in which simultaneity was an entirely random result of horizontal textures, to the most cautious, subtle expressiveness of Webern's chromaticism.