The student is responsible for their own learning process. It is he who builds knowledge, who learns. The teaching focuses on the constructive mental activity of the student, it is not only active when it manipulates, explores, discovers or invents, but also when reading or listening.
The constructive mental activity of the student is applied to the contents that he already has in a considerable degree of elaboration.
The student reconstructs objects of knowledge that are already elaborated. For example, students build their learning process of the written language system, but this system is already elaborated; the same happens with algebraic operations, with the concept of historical time, and with the norms of social relation.
The fact that the constructive activity of the student is applied to pre-existing learning contents, conditions the role of the teacher. Its function can not be limited to creating the optimal conditions for the student to display a rich and diverse constructive mental activity; the teacher becomes a facilitator who should guide this activity so that the construction of the student progressively approaches what the contents mean and represent as "cultural knowledge", based on meaningful learning.