Constructivism claims to be a postepistemology that replaces "traditional" concepts of knowledge. Supporters of constructivism have argued that progress requires that pre-service teachers be weaned off traditional approaches and that they should adopt constructivist views of knowledge. Constructivism appears to be gaining ground rapidly and should no longer be viewed as an exercise in radical thinking primarily aimed at generating innovative teaching. It has become an integral part of the pedagogic mainstream. Close examination of the theoretical foundations of constructivism, however, reveals that the basic assumptions of constructivism are flawed. Far from being a postepistemology, constructivism simply regresses to a pre-Renaissance mindset with theology replaced with a psychologism. Constructivists should be aware that the implications of constructivism for future generations may be both profound and non-benign.