In the twentieth century, the visual arts have embarked on major experimentation, from cubism to expressionism. While tastes always vary, there are certainly some people who find beautiful objects of each of the art movements of the first half of the twentieth century. In the latter half of the twentieth century, though, most works are so abstract or shocking that neither the critic nor the general public uses the word "beautiful" to describe them: indeed, sometimes late twentieth-century artists have, as one of their expressed goals, the creation of a work that no one could find beautiful. Whatever these artists are creating may be intellectually engaging at some level, but it is no longer art.
Which of the following is an assumption that supports drawing the conclusion above from the reasons given for that conclusion?