整體法秩序以實現正義為理念，以落實憲法之價值為依歸，而各別之法律不外具體化憲法之價值。稅法，較其他法規範較晚生成，是故，整體稅捐之法律關係，稅捐法概念須借用其他法領域概念。基此，稅法與各法領域間具有相當之交錯，然而，稅捐法與憲法、民事法、行政法、其他法領域皆為整體法秩序之一環，基於法秩序之統一性，各別法領域雖各有其規範目的，各領域之價值與內容須互相調和以避免矛盾。是故，對於事實之認定有形式與實質之觀察，稅法於認定事實、適用法律究竟應以何種關係為據。

The whole legal order is to realize justice in theory and implement the value of the constitution in destination. However, the individual laws are to embody the value of the constitution. The tax law was formed later than other laws, therefore, the legal relation of whole taxes as well as the concept of tax law adopt the concept of other laws. Thus, there are some crisscrosses between the tax law and the other laws. However, as far as legal level is concerned, tax law, constitution, civil law, administrative law and other laws fall within part of the whole legal order. Based on uniformity of legal order, although different laws have different purposes, values and contents of different laws in various field should be adjusted mutually so as to avoid conflicts, therefore, the adjustment between different laws will occur. Furthermore, there is relationship of form and essence in all laws. What should be the legal basis of finding out facts and governing law of tax law? As for this question, this thesis puts forth that substantial control relationship should be the standard of finding out facts and governing law.