School geometry fabricates the scientific minds of the future by training students to see not with the eyes of their bodies, but with the eyes of reason and logic. There is a gap between the expressed aims of school geometry, in terms of the teaching of spatial abilities to children, and the dominance of a school geometry rooted in Euclid’s axioms. Such gap is not a “misimplementation” of the curricular intentions. Rather, the gap evidences elements of the power effects of school geometry on children’s subjectivities. This study adopts cultural historical strategies to study the functioning of school geometry. It is built on the statement that school mathematics, as a technology of the self, promotes a certain type of subjectivity. This leads to problematize the ‘truths’ circulating in school geometry and, also, its effects on children’s subjectivities. Therefore, it is possible to understand the ‘gap’ in terms of how historically Euclid’s work becomes a circulating truth in scientific discourse, performing a scientific self. Hence, schools aim to shape students in order to follow the path of a scientist, not to become a scientist but to become a logical thinker, a problem solver and a productive citizen who uses reason.