Art is intended to create beauty and character.
And whatever his faults Saint-Saens did succeed in composing beautiful music (e.g. here and here).
By 1917 the tide of art had turned. In this year the French artist Marcel Duchamp exhibited a urinal as an artwork. Duchamp did not share Saint-Saens' elevated concept of art. He wrote instead that,
Art has absolutely no existence as veracity, as truth.
We still have much art today of the non-elevated kind. The latest example comes from Sweden. Sweden's University College of Arts approved as a project a student artist faking her own psychosis:
As a part of her final project before graduation, Odell pretended she was going to jump off a bridge to commit suicide. Horrified witnesses called police, who then tried to restrain the kicking and screaming Odell.
After arriving at the hospital’s psychiatric ward, Odell proceeded to scream at the medical staff who attempted to help her, even spitting in the faces of several nurses.
She was eventually restrained on a gurney and given drugs to calm her down, remaining in the hospital overnight as doctors attempted to diagnose her psychiatric condition.
Odell later revealed the whole episode was an act and part of a larger art project which won’t be completed until May.
Why did she do it?
Odell, who has a history of mental illness, explained that she was highlighting deficiencies in Sweden's psychiatric care:
"Closed psychiatric care is the most dictatorial part of society we have, through which a patient can have all their rights taken from them. [And] it certainly needs to be, as I have also been helped by it myself. But there also needs to be control; patients are sometimes not believed."
So closed psychiatric care has helped her but she was concerned that patients are sometimes not believed. And that's it. That's all it took to justify treating psychosis as a form of modern art.