Is von Glasersfeld's constructivism actually radical? In this article, I respond to this question by analyzing von Glasersfeld's main works. I argue that the essential theoretical move of radical constructivism – namely the assertion that reality is the construction of a human mind that only responds to the subjective perception of ‘what fits’ – results in a conservative vision of reality, knowledge, and education. To the extent that the friction with, and the challenge of, reality is eliminated, knowledge remains only (...) a subjective affair and the world is reduced to a living tautology. In this way, von Glasersfeld constructs a theory of ethical disengagement in which personal responsibility is de facto denied. Thus, to the extent that education entails responsibility, change, and comparison, radical constructivism is a theory that is unsuitable for education. I also attempt to argue that the equivalence between radical constructivism and relativism and nihilism that many support is i.. (shrink)