Abstract: In this thesis, the author logically and apparently discerned the differences of the normal relation, the exceptional relation, the neutral relation and the essential relation and figured out that each of them plays a different role in the lawsuits. Therefore, the author scientifically interpreted the fundamental theory of why the normal relation has to be treated as the logic foundation of the matter-of-fact inference. And on such foundation, the author scientifically establishes several fundamental conditions that often are put in use into the matter-of-fact inference. The conditions are the standards by which the matter-of-fact inference is discerned from the remaining concepts.