"The second-order cybernetics worked out by Heinz von Foerster is rightly held to be a constructivist theory, if not an a manifesto for operational constructivism. The reverse doesn't apply, however. Constructivist epistemologies do not necessarily have the rigor of a cybernetics of cybernetics. One can observe cognitions as constructions of an observer, without linking with this the theory that the observing observer observes himself or herself as an observer."