Art and Objectivity

What is good art? I found out today that I don't know. My friend, an art major is going to school essentially to find out what exactly good art is. Apparently, things like composition, lighting, technique, etc..., there are rules to art. Imagine. Art has rules! I shouldn't be surprised. Music has rules. (something I am lot more familiar with)I use the term art in reference to the works you would find in any art museum, so I am not including any type of writing or music in my use of the word art, although everything I am saying probably applies to the loose usage of the word art.
My friend claimed that professional art critics know what constitutes as good art in the same way that your mechanic knows how your car works. I had several questions.
1)Who made the rules? The car works how the car works? What is the standard of good art?
2)How does everyone enjoy art if only the experts know if its good or not? If it is true that only experts know, how much do they have to study before they're experts? Who decides that the experts are experts? If it is true that only the experts know then what the novice calls good, is different then what the expert calls good. They mean different things.
Conclusion: Art is inherently subjective.
Facts are facts and opinions are opinions. Opinions can be wrong. Facts cannot. This is obvious but at least it' stated. So to put this on simple terms. My friend's hypothesis is that there such a thing as good and bad art as an objective fact. This means that if a person who knows nothing about art likes a piece and shows it to another person who is an art expert who discredits the piece that the former person likes a bad piece of art. But this cannot be.
The earlier questions apply. Who said it was good art? Why should we believe them even if we know who they are? How does an expert become an expert? Any value we assign, or reason we come up with will not be based on anything absolute, and therefore will fall short of "fact".
You ask, "what is based on anything absolute".
Let me say this. All reason is based on possibility and probability. The best way to arrive at the probability of something is through experience and repeated experimentation. But probability is not absolute. It is not by definition. To say that something is probable is to say that something is possibly improbable. If probable is as good as reason can come up with, then absolute is yet elusive. In other words, what we mean when we say that a piece of artwork is good, is that there is good reason to for us to assume that trained artists know what they are talking about. Of course this can be disputed and no doubt has been, but the point of what I'm saying is in the case of artwork, good is based on pure ideas, and ideas however improbable that they be wrong, can still possibly be wrong, which must mean that ideas however improbable to be right can still possibly be right.
So the next question is: Is there any link between ideas and fact? There is a relationship, but not a link. If a fact is only arrived at by reason, then it cannot be arrived at by reason because reason can only go so far as probability will allow it and probable opens the door for "possibility of not being". But perhaps there is another kind of thinking that gives us access to the absolute. It is this kind of thinking that ought to be of interest to us. Reason tells us the function. "This kind of thinking" tells us the form. Let's call it faith. But faith is a confusing word. Shall we call it derb?
So we have learned that when you make judgment value about anything, be it art, or anything else, that the words you use are used within a system based on probability. And if someone corrects you, they are not correcting the correctness of your opinion, but your ability to use reason. If someone says that death is an illusion, that no one has ever died. Our experience tells us that this is such a poor use of reason that this person ought to be locked up, but it does not mean that they are wrong. It just means that they probably are.