Research evidence has demonstrated that pedagogical techniques variously known as discovery learning, problem-based learning and constructivism are less effective than explicit instruction, especially when applied to the teaching of novice learners. Nonetheless these ineffective techniques have many devotees and re-enter the educational arena "re-badged" after each empirical revelation of their deficiencies. This article argues that constructivism and its pedagogical relatives are continually "rediscovered" because they accord with deeply held beliefs about the nature of human beings. The origins of these ideas are traced to the writings of Rousseau and the Progressivist thinkers of the nineteenth century and the ways in which the misreading of theorists, such as Piaget, provide "scientific support" for these is explored. (Contains 4 notes.)