Recent developments in the standardisation of learning technology have resulted in models of learning activities and resources including descriptive metadata and definitions of conditional flows for multirole activities. Nonetheless, such "learning designs" are actually representations of the "results" of the design process and do not provide information about the "rationale" of the design, ie, about the theoretical standpoints, assumptions or guidelines applied to come up with the concrete arrangement of activities. These latter elements are critical not only for informative reasons, but as a medium towards the end of connecting theories and hypotheses to actual practice and analysing the resulting empirical data as a form of inquiry on the validity of theoretical assumptions. This paper delineates the main aspects of a schema for the recording of such design rationales using an ontological approach. The method for the engineering of the schema was based on connecting the definitions provided with an existing large ontological base, thus reusing a large amount of common sense knowledge. Two paradigmatic example positions of the range of aspects that could be covered by the representation language are described as an illustration. The resulting ontological definitions can be used as a foundation for the refinement of theoretical positions and for their comparative assessment.