What Is the Mind Body Problem?

The mind body problem is a question of how two different realms can relate. The soul does not seem to take up space, or at least not in the same way as physical objects. It has no definite location in space, and it's not the sort of thing that can be publicly observed. And i can introspect my mind, and you can introspect yours, but i cannot observe your mind, nor can i introspect your mind. How can something which is non physical impart an impulse? How can it touch or contact a bodyd?"