There are many definitions of art, rising and falling in popularity at different points in human history. The loosest definition of fine art today is artifice: the creation of a thing, not by nature itself, but by the will of a person or group. It can be visual, meant to be seen; it can be music or poetry, meant to be heard; it can be a novel to read, a play to watch or a dance to take part in; it can be buildings or clothing; digital or virtual; it can be the disciplined training of plants or animals. So broad is the possible definition of "art" that some say one can make an art out of living life itself. This definition, however, is not complete, because it includes many things people do and objects created that we do not consider art. So, what separates a painting from a carburator? Here again, people try to make a distinction through over-simplification: art is anything made, lacking useful purpose. This is also a fallacy, as fine art also serves many purposes, crucial to society. In more familiar terms, art is usually defined as that which was made in order to express feelings, communicate information, make a philosophical point, entertain someone, or beautify one's surroundings.
Art is differentiated from science in two ways. First, the definition of science and its branches are not widely debated, whereas art is. Second, scientific study relies on observation, experimentation, and peer revue, with one overarching goal - to increase human understanding of the universe. It's assumed that this will lead to a better way of life through better health, increased life span, more leisure time, etc. The effects of the scientific method are directly cumulative, with advances in different branches often coming together to form new insights and technology. While art also incorporates many of these same tenets and principles, it's much more chaotic, taking as many steps back as it does forward. While scientists look for puzzles to solve concretely, artists search for a way to leave a mark on the world, to comment on it, basing their work as much on intuition (or more so) as on fact. Artists often look to solve puzzles that can't be answered with science. Often times, the purpose of art making is less akin to problem solving than to a gut reaction of the artist to his/her environment, compelling one to create. In addition, while scientists share their findings in a wider community, working together to build consensus, artists often find themselves alone, ignoring vast amounts of art history and theory they find objectionable. Even so, the two may overlap: scientists sometimes feel that their work approaches the aesthetic dimension of art; artists sometimes feel that they have explored their subject matter with scientific precision.
Throughout time, art has not always been made by individual artists, or even by people who would dare to identify themselves as artists. Some of the most ancient and profound art is "folk art," created by anonymous people under unknown circumstances. Folk art may be religious in nature - perhaps even an attempt to create a magical object. It may have been made by itinerant or untrained artists. It may not have been considered art at all at the time of its creation. Art as we know it today, is a fairly modern concept.
In the twenty-first century, the question "what is art?" has been debated for so long that, in terms of creating an art survey text, we now tend to accept Marcel Duchamp's inclusive definition, "Art is whatever an artist says it is."
Today, we also accept that industrial and graphic design are forms of art. These forms, like the old folk art mentioned above, were once not considered art at all. But now they have taken their place alongside painting and poetry; the artisan, or skilled worker practicing a trade or handicraft, is an artist if he calls himself one. And that means art can be everywhere--from the shoes on your feet to the car you drive to the teacup you sip from. We have functional art (objects you use) and art pour l'art (art for its own sake). We have "high" art and "low" art (whatever you wish those divisions to signify), high street fashion and Haute Couture, "real" art and "kitsch".
Today's world is a world of possibility and freedom. Although it is (and perhaps has always been) fashionable to groan that "true art is dying out", such a thing can never happen. As long as there are people who want to create, there will be artists. If you look carefully around you, you will see that almost every tradition and genre of art making, ever begun, is still going strong today.