I remember seeing a doco that was discussing the 'what is art' question. My favourite response was from an eccentric artist/rancher, who had made the three letters A R T in giant vinyl-covered foam blocks, and stacked them against a fence. His opinion on the definition question "What is 'art'?": 'art' is three letters up against a fence.
My favorite definition is in this footage of Gordon Pask speaking of the liberty to adventure, not limited to artists but also very common to sciences. Art and science are ways of questioning or proving asumptions about the world and that requires to asume risks. There is no risk in mastery.
https://youtu.be/fifSXXS8fU4
