Art is a piece of work that visually evokes wonder, beauty, or thought.
My brother is a photographer in South Carolina and works in an art studio owned by an older man, Jon Beksham. When I toured the studio this summer there was one piece of art that caught my eye; it was a black-and-white picture of a young girl starring up at a huge tree. I must have spent a half hour looking at this picture because I felt dejavew (don’t know how to spell it) when I first laid eyes on it, and it continued to make me wonder as I stood in front of the canvas. The picture was immediately recognizable, but for the life of me I couldn't determine from where in my past the recognition had come from. The photograph, which stood out to me more than anything else in the studio, wasn't necessarily the most beautiful piece of art I had ever seen, but the sensation of remembrance that it created when I first laid eyes upon it was palpable.
I don't think Mr. Beksham was planning on anyone making such an attachment to that particular picture, but that personal experiences can change what a person thinks is beautiful or not.
From what I understand (which could be totally wrong), Thierry de Duve is saying that anyone can be a critic of art, and that criticisms are based on personal backgrounds. He also says that art has been judged based on a critics liking or disliking (i.e. "I think the Mona Lisa is beautiful, therefore everyone should think it's beautiful) instead of a society's acceptance of certain art works. De Duve disagrees with this method of judgment, and I think he is right. One person should not decide what id beautiful, or what is art, but societies and the various people of the world should decide for themselves.