For either all works of visual art have some common quality, or when we speak of "works of art" we gibber. Everyone speaks of "art," making a mental classification by which he distinguishes the class "works of art" from all other classes. What is the justification of this classification? What is the quality common and peculiar to all members of this class? Whatever it be, no doubt it is often found in company with other qualities; but they are adventitious--it is essential. There must be some one quality without which a work of art cannot exist; possessing which, in the least degree, no work is altogether worthless. What is this quality? What quality is shared by all objects that provoke our aesthetic emotions? What quality is common to Sta. Sophia and the windows at Chartres, Mexican sculpture, a Persian bowl, Chinese carpets, Giotto's frescoes at Padua, and the masterpieces of Poussin, Piero della Francesca, and Cezanne? Only one answer seems possible--significant form. In each, lines and colours combined in a particular way, certain forms and relations of forms, stir our aesthetic emotions. These relations and combinations of lines and colours, these aesthetically moving forms, I call "Significant Form"; and "Significant Form" is the one quality common to all works of visual art. At this point it may be objected that I am making aesthetics a purely subjective business, since my only data are personal experiences of a particular emotion. It will be said that the objects that provoke this emotion vary with each individual, and that therefore a system of aesthetics can have no objective validity. It must be replied that any system of aesthetics which pretends to be based on some objective truth is so palpably ridiculous as not to be worth discussing. We have no other means of recognising a work of art than our feeling for it. The objects that provoke aesthetic emotion vary with each individual. Aesthetic judgments are, as the saying goes, matters of taste; and about tastes, as everyone is proud to admit, there is no disputing. A good critic may be able to make me see in a picture that had left me cold things that I had overlooked, till at last, receiving the aesthetic emotion, I recognise it as a work of art. To be continually pointing out those parts, the sum, or rather the combination, of which unite to produce significant form, is the function of criticism. But it is useless for a critic to tell me that something is a work of art; he must make me feel it for myself. This he can do only by making me see; he must get at my emotions through my eyes. Unless he can make me see something that moves me, he cannot force my emotions. I have no right to consider anything a work of art to which I cannot react emotionally; and I have no right to look for the essential quality in anything that I have not _felt_ to be a work of art. The critic can affect my aesthetic theories only by affecting my aesthetic experience. All systems of