Constructivism as a Referent for Teaching and Learning
Kenneth Tobin and Deborah Tippins
Von Glasersfeld ( 1992, 5) noted that from the beginning of the 5th century B.C., the skeptics have shown that it is logically impossible to establish the "truth" of any particular piece of knowledge. The necessary comparison of the piece of knowledge with the "reality" it is supposed to represent cannot be made, because the only rational access to that reality is through yet another act of knowing.
Von Glasersfeld ( 1992, 6) wrote that constructivists, unlike the skeptics, endeavored to break away from the perennial paradox associated with the requirement that knowledge represent an independent world
and admit instead that knowledge represents something that is far more important to us, namely what we can do in our experiential world, the successful ways of dealing with the objects we call physical and the unsuccessful ways of thinking with abstract concepts.
Critics of constructivism (e.g., Matthews 1992) often make the accusation that constructivists deny the existence of a reality. Whereas some constructivists might do this, we see constructivism as a form of realism in the sense that the existence of a reality is acknowledged from the outset. What constructivism has to say about that reality, however, is that we can only know about it in a personal and subjective way. To take the example of gravity, a constructivist position is that gravity exists and through our experiences we come to know about gravity. Our knowledge of gravity is both individual and social, and through negotiation, agreement is reached within our social system that the concept of gravity has numerous verifiable properties. We construct a model of gravity that is viable in that the model fits experience, but no matter