NOTATIO

The following passage occurs at the end of the first movement of Beethoven’s piano sonata op. 101: "What’s up" with the down-stem on the high E? Plenty of room up there for an up-stemmed note.

Here is the first edition which, as usual, follows the original notation:
But a later edition of the time corrected this passage to the more expected notation, which has persisted ever since:
But don’t the A and B really lead to the C sharp, not the E? Casella attempted to show this in his edition:
While this voice-leading might explain why Beethoven didn’t beam the A-B-E together, it doesn’t explain why he didn’t just make the E a single up-stemmed flagged eighth note. In other circumstances, this would probably have been sufficient alert for thoughtful players.
The diagram above shows why I think Beethoven choose the notation he did. The E has been an important arrival point in the movement and is destined to move scale-wise up to the A to end the movement. But before it does, it makes a two-octave journey that threads its way upward through other melodies. At point X just before it jumps up the final octave, it must be written as a down-stem note because a middle melody crosses over it, the A-B-C sharp just discussed. When the E then jumps up an octave, Beethoven continues for a moment to write a down-stem E in an attempt to show this voice-leading path. An immediate up-stemmed E would have signaled the entrance of a new still higher voice, rather than the continuation of a previous one.

That is some sharp analysis, John!

Thanks so much, JJP. I really appreciate the feedback and the compliment!