The document presents a novel approach to constructing learning hierarchies using fuzzy logic, addressing the often ignored fuzzy relationships between skills' prerequisites in adaptive learning systems. The proposed method involves defining an initial learning hierarchy established by experts, measuring variations in learners' grades, and applying fuzzy logic to reassess the correctness of these relationships. Ultimately, the approach aims to enhance the customization of instruction by integrating fuzzy set theory to better represent the complexities of student learning paths.