The search for a definition of Art has been the subject of a complex philosophical reflection incorporated; however, within different themes, because the very idea of ​​Art is changeable because it is based on the culture and tradition of a particular era. Etymologically, the word Aesthetics derives from the Greek àisthesis, which means perception by the senses. It was formerly called the study of the world of perceptions, the doctrine aimed at discovering the complexity of perceptual knowledge. In ancient times the concept of art was closely linked to the practice of technique which, according to Plato, was certainly not positive. .According to the philosopher, Art and Tragedy are copies of copies, copies of the sensible world. He argues that there is a crisis on the moral level: art encourages and stimulates the passions inciting human beings to approach it. For Aristotle, on the contrary, the creation of a work of art allows the materialization of an idea and then its manifestation. According to the philosopher, beauty is order and symmetry and Art represents its imitation, without limiting itself to the reproduction of the sensible world. There was then a complete re-evaluation of the concept of Art that Plato despised, with new ideas explaining that Art represents not the imitation of the sensible world, but of ideas themselves. In other words, Art imitates the universal. Furthermore, Aristotle introduces the term "catharsis" or purification, showing how Art allowed the rationalization of the passions and their consequent control. It was not until the 18th century that the independent philosophical discipline related to the beauty of art, namely aesthetics, became an effective method of study.The German philosopher Baumgarten,...... middle from article......The Stanford Encyclopedia of Philosophy (Winter 2012 edition), Edward N. Zalta (ed.), URL http://plato.stanford.edu/archives/win2012/entries/art-definition /.Beardsley, M., An Aesthetic Definition of Art, in H. Curtler, ed., What is Art? (New York: Haven Publications, 1983) Reprinted in Lamarque and Olsen, eds. Aesthetics and Philosophy of Art (Oxford: Blackwell, 2004), pp.55-62. Dickie, G., What is Art? : An Institutional Analysis, in Its Art and Aesthetics (Ithaca, NY: Cornell University Press, 1974), ch.1. Gaut, B., Art as a Cluster Concept, in N. Carroll, ed., Theories of Art Today (Madison, WI: University of Wisconsin Press, 2000), pp.25-44. Levinson, J., Defining Art Historically, British Journal of Aesthetics, 19 (1979): 232-50. Reprinted in Lamarque and Olsen, ed. Aesthetics and Philosophy of Art (Oxford: Blackwell, 2004), pp..35-46.