Aaron J. Rabushka wrote:

>This thread marks the first time that I noticed the similarity in rhythm
>between the opening themes of the Eroica and Brahms' 2nd.  In all other
>respects (including melody, instrumentation, harmony, Beethoven's head-on
>lead attack vs.  Brahms oblique approach) they are so different that it's
>almost impossible to associate the two.

This resemblance was noted at least as far back as Sir George Grove,
in the 1890s, who believed that it was more than coincidence.  Given
that Brahms was steeped in Beethoven, and he presumably knew the Eroica
backwards and forwards, it seems likely (admittedly not certain) that an
identical distinctive rhythm through 9 notes is at the least an unconscious
reminiscence.  Of course, as has been pointed out, it's what you do with
the melody/rhythm that counts, and Brahms' theme is indeed quite different
from Beethoven's in character.

But this raises the interesting question: what elements of music are
most likely to suggest resemblance to our ears? My guess is that in most
cases rhythm is in fact more important than pitch and intervals.  Here's
a remarkable example.  Consider these two musical phrases: 1) the first
eight notes of the Scherzo to Beethoven's 5th and 2) the first eight notes
of the finale of Mozart's Symphony No. 40.  My guess is that 100 out of
100 listeners would say that these phrases had very little in common.
In fact, allowing for transposition of key, they are--believe it or
not--identical.  Rhythm makes the difference (tempo and orchestration
probably count here too).  Beethoven's sketchbook shows that he was aware
of the resemblance.  On the adjoining page of the sketchbook of the
Scherzo, Beethoven copied out the first 29 bars of the melody of Mozart's
finale.  It's even possible that Beethoven took the phrase from Mozart.

Peter