Constructivists (Von Glaserfeld, 1990) advocate models for learning based on the belief that students construct their own knowledge and understanding. The basis for learning is the set of all prior experience and the derived knowledge and understanding. As students learn, they constantly engage in the process of revising their prior learning based on new experience.
The standards for science education seem to be based on a learning theory that closely aligns with constructivist thinking. As such, they require curriculum frameworks that also align with such beliefs.
If the constructivist model is used as the basis for curriculum designed to promote reform of science education, learning theory--not discipline-centered epistemology--provides the structure. That is, as content is organized and sequenced, the students' knowledge--not the structure of knowledge--is the only appropriate basis.