Three levels of understanding

To explain the three levels of understanding, consider the following example. A student can be brought into awareness of a tool, such as the crane. The student first observes the general characteristics of the crane. He then tries to observe the details, and tries to imagine (or visualize) how the crane behalfs in action. By jumping back and forth between the higher level and the lower level abstractions of the crane, the student finally accomplishes true understanding of the mechanical principles of the crane.