The step from Webern to the post-war period seems indeed to be but a small one. Let us first summarise the achievements of Webern.

The causality and gravitational pull of tonality became things of the past. The concept of ‘musical space’ was introduced by Debussy (le temps ritmisé), Stravinsky and Schönberg, and the former two in particular departed also from development form. But it was not until Webern that the new concepts of form discussed in the previous chapter (section 1) evolved.

Two processes were evident which may seem contradictory at first sight. In the first place there was a tendency towards differentiation. In the expressionist period this had been expressed primarily in strong chromaticism, motivic fragmentation and subtle playing techniques. Differentiation was later pursued more consciously and extended to other elements, even including tempo. But at the same time there was a tendency towards reduction. This stemmed from Webern's sense of balance and comprehensibility (Fasslichkeit), and perhaps from a mystical trait which came to the fore at a later stage, a trait not unfamiliar to figures such as Schönberg and Hauer.

In Webern's early work the principle of constant variation was still prevalent. In op. 21, however, he already employed literal repetition, and thereafter the symmetrical blocks discussed previously. Although subtle shifting may occur in such mirrored structures, contrast is reduced to a minimum by reason of the fact that the primary factor is ultimately pitch. All this still gave the composer a broad margin between repetition and contrast. The influence of reduction is also felt in the series, which is mirrored in itself, limited to just a few intervals, or divided into analogous cells.

Through the pursuit of differentiation, elements that had once been secondary became autonomous. However, in Webern these remained functional, continuing to lend structure to a form that is primarily a matter of pitch organisation. The so-called punctual music of a later period was to abandon this bond too, subjecting various musical elements to coequal, serial organisation.

The pursuit of reduction brought about an attitude towards the series that was immanently present but not yet clearly manifest. The series lost its last ‘thematic’ character and became a regulating factor, creating quantitative distinctions and measurable proportions.