Wow, I just came across this thread! LOL Yup Giovanni, this kind of discussion is "right up my alley!" I was, however, dealing with a lot of stuff and was spending very little time on the internet when this started. Thank you very much for your too kind compliments!
I only have a couple minutes, because I have to leave for work very soon, but I just can't leave this one alone! So I'll make a brief statement and maybe come back to this.
My opinion is that yes, it's impossible to actually RECREATE a performance of the past, and I actually think it's not very desirable to try. Even Bach himself probably changed his approach to his own pieces as his life progressed. We all do this, at least one would hope we change and grow as we progress through life. So to try to RECREATE a given performance is to take away the vitality and life of the music, and this is, I think, one path that leads away from the mark of true communication in performance. HOWEVER
HOWEVER
I believe very strongly that it is our job as performers to honor the intentions of the great composers of the past. To ignore what can be learned of the assumptions any composer made about how his music would have been performed is, to me, intolerable and gross misrepresentation of the work of great musicians. As an example, when I was younger, it was common for pianists to ignore the articulations in Mozart's piano sonatas, saying he didn't know what he was doing and got carried away with violin bowings. ?????!!!!!!! It was also common for conductors to ignore Beethoven's metronome markings, saying either his metronome was broken or he was just crazy. ??????!!!!!!! All I have time to say at the moment is that this is remarkably selfish.
In general, I agree with what Theodor says in his posting, that the idea should be to come up with a POSSIBLE performance that the composer would have recognized. As far as the Rifkin one-on-a-part performances of Bach, well, yes Bach may have been forced to perform his cantatas that way sometime, but we have hard evidence that he DID NOT like it. So I see no reason to keep doing something that we know Bach did not like. (I don't like the sound of one on a part, either. But I also don't like 20 on a part in Bach cantatas, or the B minor Mass for that matter. That's like teaching a hippopatamus to dance ballet.)
Unfortunately, I can't write more at the moment, but this is, to me, a very important subject (one that I get emotional about, obviously)
I have a some performances coming up in a couple weeks, so I will not be on all the time, but I definately want to continue with this topic.