Beethoven's piano notation: 'dim.' vs. 'decresc.', some considerations about the agogics

Unlike both his predecessors (Mozart's generation) and successors (Chopin et al.), Beethoven lived in a moment of significant evolution both in and outside the musical world. The sudden rise of the middle class, together with rapid developments in piano construction, technique, and musical aesthetics, had clear repercussions in piano notation. As Czerny remarks in his Pianoforte-Schule (1839): «Jn den neueren Compositionen werden die Zeichen des Vortrags von den Autoren meistens so ausführlich angewendet, dass der Spieler im Allgemeinen selten über den Willen des Compositeurs in Zweifel sein kann». This trend toward more complete notational instructions occurred between the 18th and early 19th century, completely coincidental with Beethoven's compositional period. Indeed, by looking at the composer's piano sonatas, one observes a gradual and constant increase in performance indications of all kinds: dynamics, articulations, phrasing, and pedalling, among others. Agogics are no exception.
Concerning in particular the use of the marks diminuendo and decrescendo, one notices an inconsistent attitude: among the 32 printed piano sonatas, Beethoven often alternates between these two indications without an apparent difference in expressive meaning. A closer look at the last sonatas, however, will reveal some important clues that might suggest that the composer was in fact searching for a more refined way to communicate performance indications – in this case, imparting agogic implications to some marks that ordinarily pertain only to dynamics. This hypothesis is supported by an examination of the notation of his contemporaries, including Schubert, who also used these marks as performance indications for both dynamics and time.