In this essay Clarence Joldersma explores radical constructivism through the work of its most well-known advocate, Ernst von Glasersfeld, who combines a sophisticated philosophical discussion of knowledge and truth with educational practices. Joldersma uses Joseph Rouse's work in philosophy of science to criticize the antirealism inherent in radical constructivism, emphasizing that Rouse's Heideggerian critique differs from the standard realist defense of modernist epistemology. Next, Joldersma develops an alternative conception of truth, in terms of disclosure, based on Lambert Zuidervaart's work in aesthetics. Joldersma concludes by arguing that this notion of truth avoids the pitfalls of both realism and antirealism, giving educational theorists a way forward to accept some of the major insights of constructivism with respect to learning and teaching without having to relinquish a robust notion of truth.