Dear Paolo, dear friends,
I have just come across this very serious discussion and I greatly appreciated the beautiful interview published.
My ideas stem from long ago and, in an attempt to explain them, I will start with an example A ): 2+3=3+2=5.
We all believe we know this, but how many would agree with me that B ): 2+3 not = 3+2 not = 5 ?
Well, if we are counting, A is true and B is false; but if we are walking first forward and then to the right, A is false and B is true; in fact, 2 steps forward and 3 to the right brings me to a different point than 3 steps forward and 2 to the right, and the distance I have moved away is not 5 (5 is the number of steps taken).
In short, the symbols in the absence of an interpretation mean absolutely nothing, because they do not transmit information, but only misunderstandings.
And interpretation means nothing other than communicating and evoking in others sensations and feelings that are hoped to be common, but which could also be quite different! (how many times is what we say misunderstood?).
Only in the presence of an interpretation that is considered reasonably shared can the meanings represented by symbols be discussed, never forgetting that (assuming there is a reality) reality is not the symbols, but only the meanings that the symbols attempt to make accessible.
This is why there is no technique outside of music and, anyway, symbols (durations, notes, dynamics, etc., up to the movement of hands on the keys) are only tools for a, hopefully, easier communication of reality (not the one we claim exists independently of us, but the one that is created in our so-called mind).
Simon rightly cites, referring to the hand, anatomical differences, but let us not forget that among these are also cerebral ones! We assume that brains (thought) are all equal, but perhaps it is only true that they perhaps resemble each other a little!
Therefore (starting from the basics), not only does everyone have their own training path and/or finds their own technical solutions, but everyone also has their own musical sensibilities!
Does this mean then that music is "relative"?
Well, yes, I confess, even music, like any form of human activity—artistic, humanistic, historical, economic, positivist, etc. etc.—is nothing more than the world that is in our personal perception of the intellect (be careful not to assume that it is real!).
But, so what? Why play? Why compose? Why express oneself?
Very simply, because this is how we tend to understand more and better and, ultimately, to improve our race.
Finally, regarding the wider dominance of music over other arts or human activities, I believe it is nothing more than a "beautiful illusion"", which I too love to share. It is worth remembering here Giambattista Vico, for whom Music belongs to the first stage of the evolution of human language; which then leads to its wider dominance.
Let us not forget that perhaps the only human activity without boundaries is the cerebral one, since each language (and therefore also musical, pictorial, poetic, mathematical, etc. languages) is just an attempt to define symbols and an interpretation to communicate.
And so? Nothing, just follow what makes us feel better day after day and do not be enchanted by false prophets!
In other words, seek oneself and be proud of who one is and what one does.
For me, this means that when I play, if I am moved it is music (mine) and if I move others it is music (others'); when I read a score enjoying it it is music (mine) and—listen, listen—one day a lovely lady, passing by me while I was reading a little something by Grieg, told me that I had a happy face (we had a music of our own).