Is Art Art?

There was a pianist who just sat behind a piano for 4minutes and 30 seconds and called it an art. Some people may say this can't be an art, but I thik this can be an art for 3 reasons: art is free from a form; silence can be an art; art is not for money.
First of all, art dosen't have to keep the form. If the art is a standardized form, there would be no need for an artist because every one can be an artist only if they learned what art is. The style and form totally depends on the artist and piaist is an artist. So if the piaist considered the performance as an art, it's an art.
Secondly, silence can be an art. As I mentioned before, art has no form and, in my opinion, if a person can feel something from it, it can be an art. Also sometimes silence can give a person inspiration and impression more than any other things. So if someone felt something during the performance, it can be an art.
lastly, some people won't pay for the pianist's performance. Then soon the pianist won't be able to earn any money. If the pianist worried about the finencial problem, he won't be able to perform the 4 minutes and 30 seconds. But art is not a money making and may be this is the reason the pianist performed although he knew that he won't get money from it.
Now to conclude, art can be whatever the artist think and want to show other people without considering the money the artist can get from it and silence can be something that the artist wanted to express. So I think the 4 minutes and 30 seconds as an art.