Current methods for teaching about "force and motion" depend on the use of equations and do not place emphasis on adequately supporting an understanding based on causality. One possible reason for this is the lack of a causality-compliant theory that gives a consistent treatment of the problem of action and reaction, the problem of apparent forces like centrifugal force, and so on. By adopting a naive view of causality (causality-based understanding) that agrees with human experience, we constructed a causal theory of force and motion. This theory can serve as the foundation for an educational approach in helping junior high and high school students understand and explain various phenomena related to forces and motion. Using this approach, it will be possible to design and develop educational support methods and systems expected to reduce student misunderstandings. It will also afford the creation of a general-purpose motion simulator with the ability to provide automated causal explanations of physical phenomena.