What is art? A question without a sensible answer.

What is art? When does it differ from design?  Everyone is entitled to a completely different point of view and that helps the world to go round.
There are, however, a few constants.  Art usually provokes a reaction and is a sensory stimulus or sensory deprivation. Polish artist Miroslaw Balka's 'How It Is' (after Samuel Beckett's 1961 writing) a light less steel chamber, the tenth commission for the Tate Modern's Turbine Hall, forces the spectator to wander into a black void, an unusual experience especially considering the awkward social interactions (and intimacies) it forces.
Art can also be a means of conveying information.  Most early art was figurative and educational and produced at the behest of the very wealthy.  This was the case, in the Western world, up until the Industrial Revolution when wealth began to slowly filter through society, craftspeople were re-occupied with artisanship and the increased literacy rates among society meant that Religious art was not as important a tool as it had been.
For the artist, or the author of the piece, whether working freely or to a commission, the act of creativity can encompass many things.  Artistic endeavor can allow for the expression of opinions and emotions; a form of self-help in several ways.  For the artist and the viewer alike, art can allow for the experience of an altered or alternate reality.  The mundane, placed out of context, changes one's perception of it and this can inform other situations.  An improved or idealised reality can be a form of escapism or it can be a commentary on why the reality with which we are familiar needs to be improved.  This is how I interpret the phrase 'to hold a mirror up to reality'.

I have never heard anyone say that art is not a subjective or divisive experience; even if it is simply the financial bubble in which art exists.  This is mainly due to the baggage which all people carry about with themselves and rummage through when they are forming a judgement on something new. This links into the opinions of German philosopher Immanuel Kant (1724 - 1804) for whom the concepts and categories of the human experience are a product of the structure of the human brain/mind with again is shaped through learning and society.  He argued that a fundamental to all humans is freedom and this is evidenced by the variety of opinions and views which individuals are able to form.  French philosopher Rene Descartes (1596 - 1650) formulated the concept of Descartes Theatre, an imaginary locale in the brain where all sensory inputs are brought together to provide the 'viewer' or self with an illusion that they are viewing a real-time version of that which surrounds us, rather than a delayed synthesis of differently timed nervous impulses.  A lot of the experience of art is very context dependent.

Art is staged.  This gives it context, whether intentionally or not, and this determines the footfall past the piece.  In a gallery, the clientele are likely to have sought out the location,  possibly researched the exhibited works and to be people with an interest in art.  Public works, whether council commissioned or graffiti, will probably reach a larger and more varied audience, but the most vociferous of these will be those to whom the work has caused offense or those who simply dislike it.

What is Art? A question without a sensible answer.

It has been suggested that Damien Hirst (1965 - ), a former Young British Artist , in many of his works, although primarily about death, has attempted to remove the stimulating sense of art.  In his piece The Physical Impossibility of Death in the Mind of Someone Living, Hirst displays pure biology and invites the viewer to observe the work of nature and the skill of the preserver.  However in his piece The Golden Calf he adds gold horns and hooves to a cow in formaldehyde, he intentionally embellishes nature with something (gold) which has a long history of being attractive to the human eye and of association of value.  This seems to go against the idea removing stimuli. 

This leads to a further question as to what is modern art.  Historically classified by the French Academy into genre, landscape, portrait and also ranked in importance, art before photography was a simpler affair.  Modern art might be something new to a particular culture, but if it ancient elsewhere, in our global community, it is unlikely to be classed as such.  There are very blurred time constraints when defining modern art; something produced half a century ago may be considered just as modern as something produced ten minutes ago.  Money is driving force in today's market and the buyers and galleries are the ones with the power to force categorisation.  Money drives hype and marketing and the current market is controlled by these things, leading to the production of Shock Art of very little consequence.

For the most recently produced and least influenced art being produced it might be useful to look to art of the streets.  Graffiti, although heavily stylised by the 1990's New York Hip-Hop music scene, it is largely anonymous and not-for-profit and therefore egalitarian, even if not widely welcomed.  However, in recent years, in the wake of American Keith Haring (1958 - 1990) whose work is so commercial it decorates ceramics by Villeroy and Bosch, the interiors of Japanese shops and t-shirts, and Banksy, whose  stencil style social commentary graffiti has become internationally recognised and valuable, graffiti may be changing too.

There are no answers to what is art, just more questions.