"The study of the way in which the arts mirror developments in mathematics is a fascinating one. Lipman Bers began a memorable lecture on non-Euclidian geometry by comparing the Declaration of Independence with Lincoln's Gettysburg Address. "We hold these truths to be self-evident," he rumbled in his Russian-accented English, quoting the Delcaration, "that all men are created equal." And then he cited Licoln's enormously cagy address: "... conceived in liberty and dedicated to the proposition that all men are created equal." The class of native-born Americans realized with a shock that Bers had discerned something we had never seen: Lincoln's frank unwillingness to commit himelf unequivocally to the propositions he was citing. Why the difference? Bers would ask. The discovery of non-Euclidean geometries in the early part of the nineteenth century, he would rumble on, an interesting if playful and irresponsible answer."