A concept is always just a guide and does not claim to be the last word in wisdom. In order to enable adequate learning, we have to do justice to the children. We can do that if we provide the psychological stages of development according to material and tools. In this way, the children express their inner tendencies. They express what they would like to do. We can help them reach their goal.
Human development is not linear, but happens abruptly in the sense of a mental metamorphosis. The leaps from one psychological stage to the next are expressed in crises. They alarm the restructuring of the protective mechanisms. The embryo, the infant, the toddler, the preschooler, the schoolchild, the adolescent protect themselves, autopoietically - in the sense of self-organization - according to their respective biopsychosocial constitution.
The founder of the crisis theory is L. S. Wygotski, the theory of self-organization is represented by H. Maturana and F. Varela.