It is generally agreed among philosophers that there is an important distinction between the aesthetic qualities of objects, especially art objects, and their nonaesthetic qualities. For example, there is a quality difference between being serene, stunning, or elegant and being square or weighing three pounds. The concept of an aesthetic quality is a philosophical one, not in general use, but aestheticians appeal to it in clarifying the practise of art criticism, justifying aesthetic judgments, and evaluating artworks.