My comments about performance and competitions on this forum have been consistent and I believe practical, and are meant to help those who have experienced bad luck at competitions or performances to learn to trust their own instincts and believe in what they are doing, rather than apologizing for their performances, their interpretations, their pedaling, their body/facial expression, their suit, etc. I have a great deal of experience with competitions, winning some and losing some. And I am just sharing with people what I wish someone had shared with me when I was still 12 years old.
But to quickly address your point:
I didn't say art, I said MY art. My art is playing an instrument and interpreting the music written by either myself or someone else before me. Sometimes I do this in front of an audience; this is called performing. But, performing is only a small part of what we do. Audience or not, I have sufficient judgment and experience to determine whether my playing at any given moment is art, whether it be in the practice room by myself, or in front of 2,000 people. The opinion of someone else is of incidental importance at this point in my life. At some point, an artist has to become convinced of his own artistry, and this confidence must be to the exclusion of everyone else. Whether an artist performs for an audience of music lovers or for a jury, the only opinion that can matter is the artist is his own. We all start off knowing nothing of art, we study for years and years, and hopefully, one day we become self-aware, so to speak, and we feel comfortable enough in our own shoes to brush off both criticism and praise. If your self-value at any given moment is determined by what others think of you at any given moment, then you are a very miserable person indeed. This is basic psychology.
The premise of your argument seems to require that art must always involve another person. If I were the last person on earth, walking through the forest, and decided to carve out a statue from a tree, it would be art - my art. Why do I need anyone else to tell their opinion of my carving, or to approve or disapprove? If I then dropped dead, thus leaving no one else alive, I believe my art would then mean nothing, because the most basic definition of art is to create something that can affect the senses. If no one were alive, there would obviously be no senses to affect, effectively disaffecting its effect, or something to that effect.

Of course, my definition of art is influenced by culture and those before me, and is a total of my experiences. You ask, "Do You exist, or are You just reflections from others?" as if these ideas cannot coexist. I am both, but to be an artist, we have to believe in ourselves first, and without qualification.
This is really an existentialistic line of thought that I am reluctant to spend much time on because were we to embark on this journey, it would take several lifetimes to discuss, because then we get into "what if X never existed" or "what if person A never heard that piece" and blah, blah blah. Again, you always bring up philosophical questions, and they are mostly interesting; they keep us on our toes. That is why we love you, Willcowskitz (except for the time when you, not having read the U.N. resolutions, formed an opinion anyway, then wanted me to do the work and summarize them for you. That was when
that conversation ended). But I am interested in the application, i.e. how does a person value their own artistic vision, how does this translate into their performances, and what are practical reasons to compete or not to compete.
You see, the very act of competing can be dangerous, because you are in a sense loaning your artistic value to the judges for the duration of the competition, and they render a verdict. But, this is the unhealthy way to compete. To compete healthily, we must hang on to our self-value regardless of the opinions of others or the outcome of the competition. When people become upset when they lose, they are admitting to themselves and everyone else that they have little self-worth. If they had artistic vision, that vision would sustain them through every obstacle they might face. How one handles defeat is a measure of one's self-value. Why do I need person A to tell me I played piece A well? I have artistic standards of my own; I either reached and/or surpassed them or I didn't. Who cares what they think?
In my opinion, the day a person can say and believe in their heart, "This is my art. It simply is," is the day they become an artist.
Robert Henry
(And above all, learn to be happy for the winner. If you can't do this then you should not compete just yet.)