Modernism, a movement dominating the early twentieth century, is characterized by a revolutionary rejection of traditional forms in arts like music, literature, and architecture, with features such as fragmented forms and a tone of nostalgia or lament for lost authority. Conversely, the text explains that Postmodernism, current since the 1980s, shares fragmentation but celebrates it as liberation, rejecting the modernist distinction between high and popular art and favoring excess and irony.