Western art criticism is unique in that

The definition of art is open, subjective, debatable. There is no unanimous agreement between historians, philosophers, or artists.

Throughout time there have been numerous definitions of art, among them: "art is the correct ordering of reason" (Thomas Aquinas); "Art is that which establishes its own rule" (Schiller); "Art is style" (Max Dvořák); "Art is an expression of society" (John Ruskin); "Art is the freedom of genius" (Adolf Loos); "Art is the idea" (Marcel Duchamp); "Art is novelty" (Jean Dubuffet); "Art is action, life" (Joseph Beuys); "Art is everything that men call art" (Dino Formaggio), "art is life, life is art" (Wolf Vostell).

The concept has changed over time: until the Renaissance, art was only considered the liberal arts; architecture, sculpture and painting were "crafts".

Art has always been one of the main means of expression of the human being, through which he expresses his ideas and feelings, the way he relates to the world. Its function can vary from the most practical to the ornamental, it can have a religious or simply aesthetic content, it can be long-lasting or ephemeral.

In the 20th century, even the material substrate was lost: Beuys said that life is a means of artistic expression, highlighting the vital aspect, the action. Thus, everyone is capable of being an artist.

The term art comes from the Latin ars, and is the equivalent of the Greek term τέχυη (téchne, from which 'technique' comes). Originally it was applied to all the production carried out by man and to the disciplines of know-how. Thus, artists were as much the cook, the gardener or the builder, as the painter or the poet. Over time the Latin derivation (ars - > art) was used to designate the disciplines related to the arts of the aesthetic and the emotional; and the Greek derivation (téchne - > technique), for those disciplines that have to do with intellectual productions and articles of use. At present, it is difficult to find that both terms (art and technique) are confused or used as synonyms.

Within the history of Western art writing, however, is a distinct critical tradition characterized by the use of theory; theoretical analyses of art