The paper will make two claims: first, that many constructivists embrace erroneous philosophical positions that are antithetical to the conduct of good science; and second, that Constructivism as a theory of learning promotes ineffective pedagogy and poor student learning. The philosophical errors identified are those associated with skepticism in epistemology and idealism in ontology. The pedagogical problem results from constructivism ignoring or minimising the basic point that learning is dependent upon guidance and instruction, the more so in a discipline such as physics. The paper will make some suggestions about why this unfortunate state of affairs has come to pass in science education research.

Key words: constructivism, idealism, ontology, realism

Ernst von Glasersfeld (1917–2010), a cyberneticist by training, was the creator and major exponent of the amalgam of psychological, philosophical, and educational positions known as radical constructivism (RC). Constructivism more generally has had enormous impact in science and mathematics research and pedagogy from the 1970s to the present time, with review after review saying it is the most influential theory in these fields. Within constructivism, von Glasersfeld’s RC has commanded a large following. Von Glasersfeld published well more than 100 papers, book chapters, and books in fields such as mathematics and science education, cybernetics, semantics, and epistemology. Two important books are Construction of Knowledge (1987) and Radical Constructivism: A Way of Knowing and Learning (1995); his major articles are gathered in Key Works in Radical Constructivism (2007). He was a philosophical autodidact who acknowledged Giambattista Vico (1668–1744) and Bishop George Berkeley (1685–1753) as the two major influences on the crafting of his own RC theory with Jean Piaget as the modern theorist from whom he took most inspiration.

Key words: radical constructivism, ernst von glasersfeld