Despite official government srt (in various jurisdictions around the world) for providing students with opportunities to construct their own knowledge within the context of formal schooling, school science systems continue to place greatest priority on teaching and learning of "products" of science (e.g., laws and theories), while compromising students' opportunities to develop realistic conceptions "about" science and expertise for "doing" science. Based on qualitative data analyzed using constant comparative methods (based on constructivist grounded theory), we found this also to be the case--paradoxically--in a school belonging to the Canadian Coalition for Self-directed Learning (CCSDL). Schools in this coalition espouse, among various goals, enabling students to construct their own knowledge, in ways and directions suiting their individual needs, interests, perspectives, and abilities, in addition to gaining access to knowledge developed by society. The science department within the coalition school in this study experienced considerable difficulty realizing this goal, despite school-level administrative support for a concerted effort to reinvent itself along these lines. Factors that appeared to influence the science department's efforts included those in each of Schwab's (1969) educational "commonplaces;" that is, the "curriculum, teachers, students," and the "milieu" surrounding teaching and learning. Further analysis suggests that results can be explained through reference to a Kuhnian (1962/1996) paradigm conflict--in which the school's administrative and curricular committee and other members of the CCSDL were unsuccessful in convincing members of the science department (who, in turn, appeared to be supported by the provincial government, parents, and students) to make provisions for more student-directed, openended science inquiry. Assuming that student-led scientific inquiry continues to be an important curricular goal, efforts must continue to be made, therefore, to convince members of the mainstream paradigm that it is a worthy goal.