In my article, I discuss building the organ of relational-abstractive activity
(RAA) and the birth of causal thinking in mathematics. I draw on the work of Vít and Milan Hejný, in which they focus on the need to teach children to think autonomously and to use causality. Causal thinking in mathematics is born out of the recognition of social causality. The idea of what a proof is is different for a teacher and the pupil's. This often leads to misunderstandings.