How important is the pulse in performance?

[paxxx17]

The way I perceive classical music in general is without a strong sense of pulse. For example, Fur Elise is written in 3/8 and the first measure is upbeat (last 8th note), but I hear the first measure as 4/8 (starting regularly on a downbeat) which then shifts to 3/8 for two measures, one measure of 2/8, then repeat (back to 4/8, etc)

When performing, how important is to paint the pulse exactly as written? With Bach and Mozart I assume it's very much so, but with later composers it gets quite a bit fuzzier.

One can hear that even the professional pianists sometimes disregard the pulse.* Let's take Cziffra's performance of Feux follets as an example:

If one analyzes the score, it will be quite evident that Cziffra doesn't respect the pulse (he even skips some rests and adds them where they're not supposed to be). The most notable example of his disregard of the pulse is at 3:58 where this four-note descending group is repeated 5 times. He plays it 6 times instead. Such a mistake can only happen when the performer doesn't take pulse into account

So, how important is the pulse? Did the composers sometimes write the bar lines just as a formal necessity while the music isn't really supposed to have indicated pulse? Or should the performer always try to portray the pulse as the written bar lines suggest?

*Note that playing rubato isn't the same as disregarding the pulse. One can play a lot of rubato but still follow the pulse as written

[themeandvariation]

I think you are confusing the pulse with the bar line.
In Fur Elise, the pulse stays the same, but the sense of phrasing sometimes carries over the bar line, thus obfuscating where the downbeat of a measure begins. This is done deliberately by the composer to create some complexity in this regard.
Like as you said, one perceives it "For example, Fur Elise is written in 3/8 and the first measure is upbeat (last 8th note), but I hear the first measure as 4/8 (starting regularly on a downbeat) which then shifts to 3/8 for two measures, one measure of 2/8, then repeat (back to 4/8, etc)".

Then you say "With Bach and Mozart I assume it's very much so, but with later composers it gets quite a bit fuzzier." Yes, Mozart doesn't 'hide' the bar line so much, but in Bach's fugues, the bar line is suspended or lost - to the ear.


 

[lelle]

The pulse is very important, but you can still sculpt phrases with a natural rise and fall of the pulse, take an extra micro moment before landing on an important chord, marking the start of a new section, etc. One interesting rubato tip I have been given is that you always play strictly in time, it's just that you change the beats per minute, for example from motivic fragment to motivic fragment. So the pulse is strict, but can vary.

[jamienc]

It’s one of the most important aspects of communicating the intent of the composer. Fur Elise is a great example of how disorienting (and incorrect) it is to begin the piece as if the first two notes are the downbeat. If interpreted and performed as an anacrusis, the true downbeat (the third and fourth sixteenths of the right hand) will properly orient the listener to the triple meter and will avoid causing the 4/8 feel that “changes” to 3/8 in the next bar. In other words, don’t stress the first sixteenth and you’ll have the pulse correctly placed.

[lelle]

It’s one of the most important aspects of communicating the intent of the composer. Fur Elise is a great example of how disorienting (and incorrect) it is to begin the piece as if the first two notes are the downbeat. If interpreted and performed as an anacrusis, the true downbeat (the third and fourth sixteenths of the right hand) will properly orient the listener to the triple meter and will avoid causing the 4/8 feel that “changes” to 3/8 in the next bar. In other words, don’t stress the first sixteenth and you’ll have the pulse correctly placed.

Good point regarding OP:s question on Fur Elise. @OP If the opening to Fur Elise sounds like 4/8 when they play it, it's because the pianist is not showing the pulse properly, not an inherent issue with how classical music handles pulse. Sadly, there are some pretty big pianists today who do not show the pulse correctly (you can do that even in very lyrical music that demands rubato and anything but mechanical playing even with very subtle stresses and shaping of the phrase).