I think the foundational assertion of a Modernist, and I am generalizing here, is that Truth is relative. That each individual has his or her own experience of truth and that each version is equally valid. As a Realist one would necessarily say that there are universal truths, which is the type of truth I think you were alluding to Jeffery. Modernism's attempt at expressing this belief through art has lead to the
rejection of a common symbolic language in art. This pursuit to eliminate any commonality lead to the inevitable nihilistic end. The art created by Modernists, again generalizing, yields a truth valid only to the individual who created it, and sometimes not even then. So what value would that art have to any other individual? By it's own definition, no value at all. Realists then ask why it is produced at all? (A good deal of what goes on here on this board.) A realist would believe that if a work is produced it should express something about universal truths. To touch on what Iian was saying.... That expression of universal truth would be derivative of a commonality of experience or belief between the individuals. To reference that commonality artists use symbols. These symbols can range from the primitive (cave paintings) to the complex (Mozart's Requiem). The conventions have changed throughout history but the idea remains the same. Artists are attempting to express truth through symbolism.