  The main goal of this article is to use the epistemological framework of a
specific version of Cognitive Constructivism to address Piaget's central
problem of knowledge construction, namely, the re-equilibration of cognitive
structures. The distinctive objective character of this constructivist
framework is based on Heinz von Foerster's fundamental metaphor of - objects as
tokens for eigen-solutions, and is also supported by formal inference methods
of Bayesian statistics. This epistemological perspective is illustrated using
some episodes in the history of chemistry concerning the definition or
identification of chemical elements. Some of von Foerster's epistemological
imperatives provide general guidelines of development and argumentation.
