At first sight, the question "what is art?" seems so daunting, high-flown and beleaguered by personal opinion and academic speculation that it hardly seems worth asking, let alone trying to answer.
The truth, happily, is much simpler. The major cause of our confusion is mixing up art with what art does. Art actually isn't any particular thing - it is the way things are made.
We talk, and correctly, about the art of cooking, the art of boat-building, flower-arranging and even the art of politics.
We say things were "done artfully" when we admire the skill with which something is done or achieved.
We talk about the "dark arts" - nowadays mainly when we talk about PR or political spin, and only sometimes about Harry Potter.
A great cake, flower arrangement, dashing yacht, piece of music or a painting is not art - they are works of art.
The clue is in the word "works". A claggy piece of half-cooked dough is not a cake; a yacht that swamps and sinks when it is launched is not going anywhere.
Both are failed products of the art their success would have represented.
Of course, we know what cakes and boats are about. What paintings, sculpture and symphonies are made for is a bit more complicated and impossible to explain in any other way than our personal experience of them - which is what they are for.
The painter, sculptor or composer, from their experience or an experience had on behalf of an entire culture, uses art to make an object which communicates that in a way beyond words.
There is a marvellous word in te reo for the moment when we feel the awe and wonder of a great object or a great song: "wehi".
Once we have had that unique experience, our lives will have been added to or changed in large ways or small.
Our experience of works of art is personal. We have them collectively - in a concert hall or theatre - but in the end it is us and the work.
An engagement between us and a work of art - and through that an engagement with the artist or the artist's culture - is how the work does its work.
If nothing happens, it might not always be our fault: the work of art might have had nothing to say or, at least, nothing to say to us.
• Hamish Keith is an art commentator