One main ‘‘meta-didactical’’ problem is the clarifi-cation of the theoretical notions that are used in the area of knowledge to analyse the cognitive phenomena,since we observe a variety of terms that have not been compared or clarified: knowledge, ‘‘savoir’’,competence, conception, concept, internal representation,conceptual image, invariant operative, meaning,etc. Progress in the field requires contrasting these tools and possibly elaborating other new ideas that
serve to more effectively carry out the intended work. It is also necessary to coherently articulate the diverse dimensions or facets implied, such as the ontological (types of objects and their nature), epistemological (access to knowledge), socio-cultural and instructional facets (teaching and learning in schoolinstitutions).