Radical Constructivism

Radical constructivism is an approach to epistemology, formulated by Ernst von Glasersfeld drawing on Jean Piaget, Giambattista Vico and George Berkeley, that situates knowledge entirely within a knower's own experience rather than in any correspondence between that experience and a world beyond it. It treats verifying such a correspondence as impossible in principle, since a knower can never step outside experience to test the relation, and it redefines epistemology instead around the viability of knowledge within experience, a break sharp enough that the position has been described as post-epistemological. This distinguishes it from milder, trivial constructivist positions that still keep the traditional idea of knowledge as correspondence while granting the knower an active role in building it. Radical constructivism is closely related to second-order cybernetics and has been influential in both educational research and the philosophy of science.