Instrument manufacture and design, playing techniques and the rest have developed immensely over decades since the 1840s, as have the ways in which and the means whereby we listen to music, whereas the scores remain more or less intact. As Robert Simpson once said, we cannot listen to the music of J S Bach as his contemporaries did because we have listened to Xenakis (and I don't imagine that Simpson referred to Xenakis very often!).
On that Xenakis matter I think Simpson was utterly wrong. When I listen to a Bach sonata I at every point try to understand what
Bach's intention was, what in its entirety was the musical effect he wanted to achieve. I have heard very little Xenakis (and I do not expect ever to hear much more!). But I have heard a great deal of Scryabine and Delius, and I do not find that that affects one iota the way I listen to Bach. . . . Well, except in one way perhaps: sometimes when listening to twentieth-century music I wonder what Bach would have thought of a particular effect, and what he might have made of such and such a possibility. But those are matters of speculation, not of fact.
It seems that you misunderstand what Simpson meant. It's not so different from a situation in which one cannot live as one might have done a century or more ago because two world wars and immense scientific, technological, social and political changes and uphevals have occurred since 1914 and impacted fundamentally on the lives of almost all humans. Simpson's intended meaning was not, of course, that one listens to Bach in the context of Xenakis or indeed any other later composer but the far more broad-brush one that all the changes in musical composition and performance - not to mention the establishment and development of traditions in performing the music of the past (which would have barely registered on Bach's own horizon) - have so coloured how we listen to music that we simply cannot respond to Bach's music in the way that Bach's contemporaries did.
Perhaps what you seem also to have overlooked is how Bach might have expected his music to be performed and received in the late 19th or early 21st centuries had he known at the time of writing that it would be. You might not think that your listening experiences with Scriabin and Delius would impact in any way upon your responses when listening to Bach, but listening to Bach in Bach's time when his was modern music and doing so today when there have been so many modern musics since is not something that can be done in such total isolation, even though the differences are usually subconscious.
conventional musical notation is only ever a guide to, rather than a precise blueprint for, the composer's intentions.
We might ask there how precise it has to be. Not mathematically accurate as in the case of the laws of physics. There are some aspects of performance which matter - the right note rather than the wrong note, a louder passage rather than softer, or a more or less correct speed. But other aspects of performance do
not matter: accuracy of intonation beyond a certain point, precise loudness levels, precise speeds. In a nut-shell, the composer's concern is with accuracy of spirit, not accuracy of measurable physical quantities, which merely have to fall within an acceptable range of variation.
One might indeed "ask", but comprehensive and conclusive answer will come there none; it is not an opinion but a fact that a composer can by no means fully convey his/her intentions merely by inputting symbols and performance instructions on and around five-line staves; I should know, although of course I am far from alone in so doing!...
Secondly, the composer's intentions are rarely if ever set completely in stone and, if they were, no composer would ever revise anything. [And] some composers have testified to ways in which performers, merely by playing their work, have even encouraged them to make such revisions.
Yes, that is all true. But it is not what happens in your average or ordinary concert. Bach for one was always tinkering with and improving his works. But this is different from the average or ordinary concert where the performer is
not expected to introduce his own alterations and suggestions.
But no two performances will ever be alike anyway, even when given by the performer him/herself; you'd have only to have heard the late great Shura Cherkassky reinventing both himself and the music every time yet without ever departing from what sounded convincingly like something of which the composer would have approved. Speaking as a composer, I am not "always right", either!
Thirdly, when composers make more than one "version" of one of their own works, the sense of the "definitive" loosens thereby.
Yes that too is true. And that too is not the average or ordinary concert situation.
Be that as it may or may not, it does mean that even the composer suggests that there's only one way to approach a performance of his/her work.
No two live performances of any work - even by its composer - will or even could be identical.
Indeed. But here it is important to distinguish between permissible variation and inadmissible variation. It is not acceptable to play a C sharp when clearly the composer specified a C natural. But the C naturals of two violinists may vary within a certain range - what is it? one
per centum? Similarly one person's
forte may differ from another person's
forte within a certain percentage; that will not matter, as long as it is clear that a
forte is played and the composer's intention is thus brought out. And yet again, the
tempi of different performances do not have to be identical, as long as they do not differ by more than a degree that is clearly acceptable to the composer. Much the same may be said of the objection about the different acoustics of different halls; what matters is not an identity of sound, rather an identity of musical contrast, intention and argument. We could even say: the music is not the sound.
The problem here is the extent to which who should decide what constitutes the permissible and the impermissible; obviously, wrong notes are one thing (as are the other examples that you cite), but as there's so much more than these various considerations in a perfomance that cannot be prescribed in a score, there will always be such variation (even between performances given by the same performer) and the lack of precise documentability (is that a word? - it is now!) of most of it is what makes for interpretative licence, some of which will be acceptable or unacceptable to some people but on which listener response and opinion will invariably be inconsistent.
Lastly, whilst certain interpretations can seem to be and indeed sometimes are less than acceptable, no two listeners will derive, or even expect to derive, the very same from a particular work with each listening.
I cannot bring myself to agree with this. I think the first duty of both the listener and the performer is to discover what exactly the composer was attempting to do.
Until the performer is satisfied that he knows that, he has no business playing the work (except in private practice of course). But in this sense all intelligent performers and listeners "
will derive, or even expect to derive, the very same from a particular work."
But all attempts on the part of listeners and performers to do that are - and indeed can in reality be no more than - journeys on a path to an uncertain and unspecific destination; one possible imminent danger in the seemingly fundamentalist way in which you appear to view this is in the misleading notion that the composer is always right, never changes his/her mind and would expect his/her music to be performed and to sound more or less the same and be responded to identically by its listeners both next week and in two centuries' time.
Of course certain modernist composers of the charlatan school direct the performer to "play whatever he likes" - but such are beneath our consideration are they not.
Aleatoric music and aleatory passages within a piece of otherwise fully notated music are somewhat outside the scope of your argument here, since different standards and expectations apply to these as one would reasonably expect to apply to fully notated music. What of improvisation in jazz - or in concerto cadenzas - for example?
