The physicist and historian and philosopher of science Stanley L. Jaki first notes that the word “pluralism” has become a euphemism or Trojan horse for relativism. Valid, sound pluralism ought to entail an education in the plurality of subject matters and a respect and understanding for their separate, irreducible integrities and also their rational relatedness to one another. A non-relativist epistemology of universal validity and scope underlies and relates all the great bodies of knowledge and learning—the natural sciences, the social sciences, the humanities, religion and theology, and philosophy itself. Unfortunately the term “pluralism” as now commonly used has confused or obscured this fundamental understanding, the invaluable legacy of rational thought since Plato. The misunderstanding of Einstein's conception of relativity is particularly damaging but typical of the misuse of modern scientific ideas by thinkers in other fields; Einstein's idea of relativity is unfortunately named, as it has nothing to do with epistemological or moral relativism, for neither of which it provides any warrant. All the subsets of rationality—the plurality of subject matters—comprise the universal set of rationality itself, a fact that Plato well understood and that needs to be understood today—perhaps now more than ever. Education need to safeguard and develop the invaluable common-sense human intuitions of the true and good as universal realities.