How can art history be explained in terms of human consciousness? What is the link between the cave paintings of primitive man and the conceptual work of artists today? What does a skull adorned with jewels (For the Love of God by Damien Hirst) or a head made out of the artist´s blood (Self by Marc Quinn) have in common with a rough outline of a bison drawn on a cave wall? It comes down to a definition of art which involves the opening up of the human mind. We could say that art is simply about employing a range of media to produce an accurate representation of the world around us, and that is good enough in most cases, but that is only half the story.Art is inseparable from its social context. It is inspired by its political, religious and intellectual environment and can change it too. Good art will always encourage change. When the first caveman painted a bison on his cave wall it would have caused a sensation because no one had seen such a thing before. Crowds would have gathered to admire it and talk about it, no less so than when Michelangelo unveiled his first David or completed the ceiling of the Sistine Chapel. It is the originality of the work, the skill gone into producing it as well as the catalytic effect it creates in our minds which makes it art. Our first caveman artist, by taking something that his tribe were used to seeing alive and running around and placing it on the wall as a recognizable reproduction, had made something completely new in human terms. In doing so, he expanded the artistic consciousness of his fellow natives, a leap from known reality to imagined reality, a leap that separated his age from the ones that had gone before, and in this way opened up an infinite number of new possibilities for the future.Similarly, every new step forward in art history is exciting and challenging because it expands the cultural awareness of its audience. This can lead to change in political or religious views. When renaissance artists began with traditional religious symbols and then introduced realism into that sacred world they paved the way for a new type of art, art which did not simply illustrate bible stories and adorn churches, but which could portray the lives of ordinary people and comment on social values. This suggested that there was something else worth preserving other than religion. Realism in art urged people to look at themselves as individuals. Rembrandt and Leonardo da Vinci were such skilled masters of their art that their portraits were as much insights into the personality of the sitter as a representation of their features.As techniques for producing photographic levels of realism were improved the way to the great neo classical works of the seventeenth and eighteenth centuries was paved, which were not only technically brilliant pieces of art, but capable of passing as social commentaries on the political and cultural landscape of their time, influencing opinion and ideas. A skilled artist could paint a compelling portrait of a political leader and at the same time fill the work with telling symbols which either praised or criticized that person´s views. The French artist David is a brilliant example of political commentary in art.With the invention of photography, artists were encouraged to search for new ways of portraying their world, such as the Impressionists who interpreted light and colour in their work. Monet, Renoir and others, broke away from the realism of the past and produced works which attempted to portray feelings and emotions through an understanding of nature.The twentieth century saw a break with the past and the change the artistic geniuses of this age brought about did not (and still doesn’t´t!) sit easily with some people. The argument as to what constitutes real art goes on. Not everyone is open to a conscience expanding experience and even now modern art is seen by some as a con. It can be years before some artists are appreciated. Picasso, Dali, Warhol, Lichtenstein, and many others in the twentieth century experimented with new perspectives, notably Abstract, Surrealist, Cubist and Pop art, reflecting trends in new technology, science, psychology and manners, but these artists can stretch the comprehension of the ordinary viewer.Today´s artists in the twenty-first century have an even bigger challenge. Everything has already been done (hasn´t it?) so finding new ways of expanding our awareness through art is becoming harder. The Turner Prize specializes in sourcing original artistic concepts and often scandalizes by doing so. In the search for conscious expanding works, sometimes errors of judgment occur. But there is no limit to human creativity and no end to the story of art. Art will continue to evolve and real breaks with the past will continue to stun audiences into new ways of thinking about the present.