"Understood system" is a philosophical treatise that examines the essence of concepts and their role in the development of science. The author examines how concepts are perceived and interpreted by people, the relationship between the concepts of various scientific disciplines, as well as the influence of concepts on the formation of worldview. The book is aimed at understanding and systematizing concepts, which helps to better understand the world around us and develop critical thinking. "System of concepts" is a work that will help the reader deepen his knowledge and expand the horizons of understanding the essence of various phenomena in the modern world.