ABSTRACT
Discussion of constructivism leads naturally into discussion of a debate that has echoed through the history of science, and that bears significantly upon the nature of science: namely that between realists and empiricists. This debate will be elaborated not just because it clarifies the argument about constructivism, but because it is so central to science that only a truncated science education can ignore it. The debate can be appreciated, if not joined, by teachers and students alike, with benefit to both. What is at issue are the goals of scientific investigation and the reality or otherwise of theoretical entities and mechanisms postulated in scientific theories to explain observable events and phenomena.
